A Mind-Controlled Sex Toy for People with Disabilities and an Exploration of Its Applications to Sex Robots

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Article User Evaluation of the Neurodildo: A Mind-Controlled Sex Toy for People with Disabilities and an Exploration of Its Applications to Sex Robots

Leonardo Mariano Gomes 1,* ID and Rita Wu 2

1 Department of Electrical Engineering, São Carlos School of Engineering (EESC), University of São Paulo (USP), São Carlos, SP 13566-590, Brazil 2 Architecture and Urbanism College (FAU), University of São Paulo (USP), São Paulo, SP 03178-200, Brazil; [email protected] * Correspondence: [email protected]; Tel.: +55-16-3373-9365

Received: 15 June 2018; Accepted: 10 August 2018; Published: 20 August 2018

Abstract: In this paper, we present the Neurodildo, a sex toy remotely controlled by brain waves, which is pressure sensitive and has electrical stimulation (e-stim) feedback. The Neurodildo was originally presented as a conference paper at the 3rd International Congress on Love and Sex with Robots (2017). We designed and explored the application of a mind-controlled sex toy for the people with mobility disabilities, for example with spinal cord injury (SCI), who have difficulty handling a commercial toy and that might experience difficulties in a sexual encounter. The system consists of the sex toy with Bluetooth and sensors, the brain-computer interface (BCI) headset, the e-stim device, and a computer for running the necessary software. The first user wears the headset and the e-stim device, and by focusing in trained patterns, he/she can control the vibration of the sex toy. The pressure applied to the sex toy by the second user is measured by sensors and transmitted and converted to the first user, who feels muscle contractions. We discuss the design process, the limitations of the prototype and how evaluating the user requirements is necessary for a better product. We also included a background and discussion on the application of sex robots for assisting disabled people and how the Neurodildo could be integrated with this futuristic technology. The goal of this project is to design a sex toy that might help people with disabilities and people in long-distance relationships (LDR), trying to fill the gap of sex toys designed for people with disabilities.

Keywords: teledildonics; brain-computer interface; spinal cord injury; long-distance relationships; human-computer interaction; sex robots; product design; sex toys; Arduino; 3D printing

1. Introduction Technology is changing faster every day, and the same happens to human relationships and interactions. People are being presented with new mobile apps that allow them to chat to each other and share their lives even if they are geographically distant. Long-distance relationships (LDR) are becoming more common than ever, considering the fact that couples have a wide range of technological options to assist them to be in contact, at least virtually. More speciﬁcally, couples are now able to have intimate or sexual relationships while distant by using internet-connected sex toys, and these devices try to reduce the lack of physical contact in LDR couples. The more the technology is developed, the more costs decrease, and electronic devices become more affordable. An important contribution to the development of technology and of new products is the open-source hardware and software, which allow more developers to work on projects and

Robotics 2018, 7, 46; doi:10.3390/robotics7030046 www.mdpi.com/journal/robotics Robotics 2018, 7, 46 2 of 21

useRobotics their 2018 knowledge, 7, x FOR PEER to helpREV IEW other people. In this work, we would like to highlight the development2 o f 19 and popularization of electroencephalography (EEG) headsets. These devices are based on research andmedical medical-grade-grade equipment equipment that thatare used are used to diagnose to diagnose brain brain diseases diseases and conditions and conditions in patients. in patients. The Thecommercial commercial EEG EEG headsets headsets led led developers developers to towork work on on a anew new area area called called b brain-computerrain-computer interfacesinterfaces (BCI),(BCI), which which consistsconsistson on usingusing brainbrain signalssignals toto controlcontrol softwaresoftware or or hardware hardware devices. devices. In the context of LDR and and BCI, we we developed developed the the Neurodildo, Neurodildo, which is a brain remote–controlledremote–controlled sex toy primarily forfor use by people with motor disabilities, forfor example with spinal cord injury (SCI),(SCI), and who are notnot able to manipulate an ordinary sexsex toy usingusing theirtheir hands.hands. WeWe focusfocus onon people with with disabilities,disabilities,but but we we do do not not exclude exclude the usethe ofuse the of Neurodildo the Neurodildo by people by withpeople a healthy with a motor healthy condition. motor Wecondition. also explore We also the explore scenario the of scenario disabled of people disabled that people have thatlimited have social limited contacts social or contacts have failed or have in attemptsfailed in attempts to engage to in engage a relationship, in a relationship, considering considering the importance the importance of the sexual of the function sexual andfunction wellness and towellness improving to improving their quality their of quality life (QoL). of life The (QoL). fact that The the fact sex that toy canthe besex used toy anywherecan be used where anywhere it can bewhere connected it can be to connected the internet to orthe in internet the presence or in the of the presence person of wearing the person the wearing EEG headset the EEG may headset enable themay person enable with the a person disability with to have a disability virtual sexual to have encounters virtual withsexual real encounters physical stimulation. with real physical We also proposestimulation. a feedback We also response propose systema feedback so that response the sex system toy may so that send the stimuli sex toy to themay person send stimuli wearing to the EEGperson headset wearing and the controlling EEG headset the and sex toy:controlling this person the sex would toy: this be electro person stimulated would be electro proportionally stimulated as theproportionally sex toy feels as the the body sex toy muscular feels the contractions body muscular pressure. contractions The Neurodildo pressure. can The be Neurodildo connected can to the be internetconnected through to the Bluetoothinternet through and a mobile Bluetooth app and or bya mobile computer app software. or by computer It vibrates software according. It v ib to r ates the receivedaccording brain to the signal received and brain sends signal proportional and sends values proportional of the attached values pressureof the attached sensors, pressure which s willensors be, usedwhich to will activate be used an e-stimulito activate device an e- connectedstimuli device to the connected wearer of to the the headset wearer (Figure of the headset1). In this (Figure stage of1). theIn this research, stage of we the designed research and, we tested designed the andtechnical tested features the technical of the features prototype. of the With prototype. this physical With andthis workingphysical versionand working of the prototype,version of wethe can prototype, preliminarily we can evaluate prelimin thearily user experienceevaluate the and user consider experience their inputsand consider for the their next version,inputs for which the next will version, be clinically which tested. will be clinically tested.

FigureFigure 1. 1. TheThe concept concept of of the the Neurodildo: a a brain brain-controlled-controlled sexsex toy. toy.

2. Background 2. Background A series of subjects was important for designing the concept of the Neurodildo, which was a A series of subjects was important for designing the concept of the Neurodildo, which was a multidisciplinary project. Due its complexity, the background research involved some aspects of the multidisciplinary project. Due its complexity, the background research involved some aspects of the sexuality of people with disabilities, the injuries (focusing on SCI) and their effects in the body. We sexuality of people with disabilities, the injuries (focusing on SCI) and their effects in the body. We also also explored the existing options on BCIs and how they could serve to our purposes, and also the explored the existing options on BCIs and how they could serve to our purposes, and also the existing existing projects and products related to disabled people, teledildonics, and mind-controlled devices. projects and products related to disabled people, teledildonics, and mind-controlled devices. We also We also conducted research on the implications of the use of sex robots by people with disabilities so conducted research on the implications of the use of sex robots by people with disabilities so we could we could discuss how the Neurodildo could integrate with this technology and help people. In the discuss how the Neurodildo could integrate with this technology and help people. In the following following subsections, we briefly explain each topic and its importance to our work. subsections, we brieﬂy explain each topic and its importance to our work.

2.1. Disability and Sexuality

Spinal cord injury has a big impact in the life of individuals that have suffered it and also on their familiars. Studies indicate that researchers focus on the motor rehabilitation of people with SCI, in particular the restoration of locomotion function. SCI causes loss of important functions, including

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2.1. Disability and Sexuality Spinal cord injury has a big impact in the life of individuals that have suffered it and also on their familiars. Studies indicate that researchers focus on the motor rehabilitation of people with SCI, in particular the restoration of locomotion function. SCI causes loss of important functions, including bladder, bowel, sexual, and sensory dysfunctions, that are not always directly visible to others [1]. Though the anatomy and physiology of SCI-induced deficits are well understood, including sexual impairments such as fertility and reproduction, these should not be the only reason for studying the sexual problems resulting from SCI [2]. In a study conducted by Anderson in 2004 [3], people with SCI have been surveyed about their desires for functional restoration, and the results showed that most people ranked sexual function in the top priorities, above the priority of regaining walking movement. In another study [2], 82.9% of the surveyed subjects stated that improving sexual function was important to the improving of their quality of life (QoL). They were also asked about the main reasons for pursuing sexual activity, resulting in 57.7% listing intimacy need as the primary reason, 18.9% for sexual need, 9.8% because of self-esteem, and 8.4% to keep a partner. Anderson also states that considering the fact that more than 80% of the participants stated that their SCI had altered their sexual sense of self and that improving sexual function would improve their QoL, it is reasonable to consider that research in this area needs to be expanded. People with SCI may still be sexual people, with desires and necessities, but certain attention is needed regarding the nature of their physical disability. The damaged nerves or blood supply can interfere with the sexual response, and it may be difficult to get into a position for making love, or there may be limitations that interfere with the foreplay [4]. In male population, for example, SCI affects the sexual function depending on the level of the lesion and its completeness. One may have its capability of maintaining erections affected, or the occurrence of ejaculation may become relatively rare or to cease. Studies on vibrostimulation indicated that using stronger stimulation parameters significantly increased the success rate for ejaculation [5]. The development and using of technological devices such as sex toys can improve the sexual function of disabled people and improve their QoL.

2.2. Sex Toys for Disabled People Sex toys are designed not only focusing on penetrative sex, and this must be emphasized while considering the design for people with SCI. A range of products is available in the market, and these products can be used as sexual aids for disabled people [6]. Cosmetics for increasing lubrication of women, massagers [7], sex furniture [8], nipple clamps, ﬂoggers, plugs, and commercial vibrators are options, but none of them are speciﬁcally made for people with disabilities. The design of a sex toy for people with SCI should consider particular aspects that may not be clear for people without disabilities. People may have limitations in the positions they can do while making love, but they can also have increased or decreased sensibility in certain parts of the body. Bowel and bladder dysfunctions, loss or impairment of hand function, decreased energy levels, and less lubrication than in healthy conditions (in the case of women) may be caused by SCI [4]. The design parameters commonly used for assistive devices for people with physical disabilities, such as wheelchairs (manual or automatic), walkers, and canes prosthetics, may provide valuable insights when designing sex toys for disabled people. A study [9] applied a method for evaluating the main factors that general disabled consumers, not only those who are physically disabled, considered when choosing an assistive device, and not abandoning it. A total of 17 factors were prioritized in this research, but the most important were effectiveness, affordability, operability, and dependability. Ferticare [10] is a Danish product designed with disabled people in mind. It helps men with spinal cord injuries to ejaculate by vibrostimulation of the penis. The amplitude and frequency of the vibrations can be adjusted with large knobs, and the device can be turned on and off by hitting its base. These features are valuable for people with decreased strength of hands, but in most situations, users would need the assistance of a carer when setting up the device and positioning it for use. Robotics 2018, 7, 46 4 of 21

Other examples of accidentally accessible sex toys are the Tantus Rumble [11], which is an ergonomic, lightweight ,and comfortable to hold vibrator; Liberator [12], which is a furniture brand that has a line of wedge-shaped pillows that can support the body during sex; Eva [13], which is a hands-free vibrator for women; Pulse [14], which is also a hands-free sex toy, but for men; and Humpus [15], which is a sex machine for men and women with interchangeable attachments and that can be used as a belt, so it becomes hands-free.

2.3. Long-Distance Relationship as a Possibility Within all the benefits that technological advances can provide for the population, we highlight the area of social relations, more specifically long-distance relationships (LDR). In the past, couples could communicate only by sending letters and after that by phone calls. Because of the internet, live video calls became feasible and popular, and more recently, mobile devices appeared as an important tool for communication. LDR may occur for different reasons, including but not limited to the demands of work, choice of careers, college studies and studying abroad programs, or the autonomy of the individuals. While LDR may be beneficial, couples face several challenges, ranging from technical problems while video chatting and time zone differences to lack of true physicality needed by most in order to support intimate sexual acts [16]. Recently, companies have developed products aimed at, but not only for, couples in LDR. The products consist of sex toys that can be connected to the internet and, in the most cases, vibrating being controlled remotely by a mobile app or computer software. These devices are part of the area called teledildonics, within the area of the internet of things (IoT). The most known IoT sex toys are the Lovense Lush [17], the We-Vibe Sync [18], and the Ohmibod Panty Vibe [19]. Most of these toys have Bluetooth connection and are able to pair with a mobile phone and, through an app, be controlled over the internet. Though these sex toys are designed for couples, they only permit the person wearing the sex toy, usually the woman, to receive stimuli controlled by the person using the app, who does not receive any sexual stimuli besides the visual feedback of the woman having sexual pleasure. People with SCI and other disabilities may benefit themselves by using services and products designed for LDR. Disabilities might make it difficult for a person to go out on a date or even to find a partner. There are some dating websites focusing on people with disabilities [20], but they can also use other dating services or mobile apps that are for general public. Another option is contacting a sex worker, but the person should fully understand the inherent risks [4]. By engaging a LDR or contacting a sex worker, a teledildonic device may be a useful resource for either people with or without disabilities. Self-stimulation by using teledildonic devices is also possible, considering that a person, even with limited arm movement, has access to and can use a smartphone for controlling the sex toy after positioning it.

2.4. Brain–Computer Interfaces (BCI) A brain–computer interface (BCI), or brain–machine interface (BMI), is a set of hardware and software system that enables humans to interact with their surroundings without the involvement of peripheral nerves and muscles. This interaction is possible by the interpretation, processing, and application of signals generated by electroencephalography activity [21]. Most researchers apply BCI to provide communications capabilities to severely disabled people who are totally paralyzed, including people who suffered SCI. The BCI can recognize certain set of patterns in brain signals by acquisition of the signals using electrodes placed on the scalp, pre-processing the signals (ﬁltering artifacts), extracting features, and classifying the signals to control the interface. Consumer-grade BCI are now available, including proprietary products such as Emotiv Epoc [22] and the Neurosky MindWave [23] headsets. Open-source projects can also be used for BCI, including the Olimex OpenEEG [24], based on the project OpenEEG [25], and the OpenBCI project [26], which is a source of useful resources like software and hardware schematics. In this work, we have chosen to use an Emotiv Epoc headset because we had it available and would not Robotics 2018, 7, 46 5 of 21 need to build the hardware by ourselves in this ﬁrst stage of the research. The Emotiv Epoc is a set of 14 electrodes and two references that are able to detect patterns of thought, feelings, and expressions in real time [22]. Researchers have successfully demonstrated that BCI headsets like the Emotiv Epoc are able to work as an interface for controlling other devices. Through the brain waves, a robot arm can be remotely controlled [27], and regarding the people with SCI, studies have combined BCI and assistive technologies for example, by developing an electric wheelchair controlled by the mind [28]. Recently, the media has published some articles about companies and designers who are exploring the possibilities of using BCI for controlling sex toys [29,30].

2.5. Sex Robots and Disabled People In recent years, the media has started publishing an increasing number of articles related to sex robots. This increase may suggest that the general public is demanding more information and becoming interested in the topic, besides raising ethical and moral issues that we have to may cope with in the near future. In the academic community, an increased number of papers and books [31,32] about sex robots and related technology indicates that the concerns of general public should be discussed in order to keep safe the future applications of this technology. According to Danaher [32], a sex robot can be deﬁned as an artiﬁcial entity that is used for sexual purposes (i.e., for sexual stimulation and release). The sex robot must also meet the following conditions:

• Humanoid form: it is intended to represent a human or human-like being in its appearance; • Human-like movement/behavior: it is intended to represent a human or human-like being in its behaviors and movements; • Some degree of artiﬁcial intelligence (AI): it is capable of interpreting and responding to information in its environment. This may be minimal (e.g., simple preprogrammed behavioral responses) or more sophisticated (e.g., human-equivalent intelligence).

By meeting these conditions, a sex robot can differentiate from other robots, for example industrial robots (which are not for sexual purposes nor have a human-like being form), and from sex toys and machines (which are for sexual purposes, sometimes represent human, in the case of sex dolls but generally do not have any degree of AI). As a promising technology in the field of human interactions, sex robots can be discussed in the context of the sexuality of people with disabilities. Many people need assistance in order for their sexual needs to be satisfied, e.g., the severely physically and mentally disabled, but also many elderly people who suffer from neurodegenerative diseases. In the Robot Sex book [32], the author Ezio Di Nucci discuss the sexual rights of disabled people and how sex robots could benefit them. Sophisticated sex robots may be able to assist disabled people and help them achieve having sexual satisfaction, filling a gap that occurs in some cases, when disabled people cannot find any other person, e.g., a partner or a sexual carer, willing to help them.

3. Neurodildo Design Process

3.1. System Overview The Neurodildo device consists of a system with three major parts. The ﬁrst part is the sex toy, which is able to communicate by Bluetooth with a smartphone or a computer. It also has a microcontroller board (Arduino) and a circuit to drive a vibration motor, allowing vibration in eight different patterns and intensities. The sex toy has also two force sensors attached to its plastic surface and under a silicone sleeve, that are able to measure and react to the external pressure against its surface. The second part of the system is the BCI headset (the Emotiv EPOC) and its control software running on a computer. The third and last part of the system is the computer-controlled E-Stim device Robotics 2018, 7, 46 6 of 21

(Electrical Muscle Stimulation), which is responsible for stimulating the muscles of the person who controls the sex toy vibration using the brain signals. The stimulation is proportional to the force applied to the sex toy sensors. The Neurodildo system works as follows:

• User A wears the Emotiv Epoc headset and places the electrical stimulation electrodes on the desired part of one’s own body; •RoboticsUser 2018 A, 7 turns, x FOR on PEER the REV Emotiv IEW Epoc and the e-stim device and sets up the necessary software,6 o f 19 including the Emotiv and the python script for communicating with the sex toy; •• UserUser B B turns turns the the sex sex toy toy onon soso thatthat itit cancan be paired with the the computer computer of of User User A. A. In In the the future, future, we wewill will develop develop a mobilea mobile app app so so th thatat User User B Bcan can pair pair the the sex sex toy toy with with a a smartphone instea insteadd of of a acomputer; computer; •• TheThe User User A A beginbegin concentratingconcentrating on the the brain brain patterns patterns that that he he or or she she has has trained trained previously, previously, for forexample example by by focusing focusing on on a pre a pre-trained-trained pattern pattern (pushing (pushing a virtual a virtual block); block); •• TheThe User User BB feelsfeels the the vibration of the the sex sex toy toy changing changing as as the the User User A Afocus focus with with more more or less or lessintensity; intensity; • • TheThe pressure pressure applied applied to to the the body body of of the the sex sex toy, toy, for for example example by aby sensitive a sensitive body body part, part, is sensed is sensed by theby force the force sensors sensors under under the silicone the silicone sleeve sleeve of the of toy; the toy; • The variation of the pressure values is transmitted through Bluetooth to the computer of User • The variation of the pressure values is transmitted through Bluetooth to the computer of User A; A; • The User A feels an electrical stimulation of his or her muscles proportional to the intensity that • The User A feels an electrical stimulation of his or her muscles proportional to the intensity that User B is pressing on the sex toy; User B is pressing on the sex toy; • The User A gets aroused because of the visual stimulation (in person or by video chat) and due to • The User A gets aroused because of the visual stimulation (in person or by video chat) and due the e-stim and then makes the sex toy vibrate more, arousing the User B, and so on. to the e-stim and then makes the sex toy vibrate more, arousing the User B, and so on. TheThe block block diagram diagram representing representing the the Neurodildo Neurodildo system system is is shown shown in in Figure Figure2: 2:

FigureFigure 2.2. BlockBlock diagramdiagram of of the the Neurodildo Ne urodildo and and its its main main parts. parts.

InIn the the following following sections, sections, we we will will detail detail each each part part of the of Neurodildo the Neurodildo system system and components and components used toused build to the build ﬁrst the version first version of the prototype. of the prototype.

3.2.3.2. Design Design of of the the Sex Sex Toy Toy TheThe firstfirst step step ofof building the sex sex toy toy prototype prototype was was the the 3D 3D modelling modelling of ofthe the plastic plastic body. body. We Wemodelled modelled the theplastic plastic body body as a cylinder as a cylinder with the with top the and top bottom and bottom ends in endsa rounded in a roundedshape. Although shape. Althoughthe name the of our name sex of toy our includes sex toy includesthe word the “Dildo” word, “Dildo”,which means which a phallic means asex phallic toy intended sex toy intendedfor sexual forpenetration, sexual penetration, our Neurodildo our Neurodildo is essentially is essentially a vibrator, a vibrator, which by which definition by definition may have may or have not ora phallic not a phallicshape. shape. We used We usedSolidworks Solidworks 2017, 2017, Dassault Dassault Systèmes Systèmes,, Vélizy Vélizy-Villacoublay,-Villacoublay, France France,, aa softwaresoftware for for modellingmodelling and and generating generating the the STL STL file, file, which which would would be be used used after after in in the the 3D 3D printing printing stage. stage. The The body body ofof the the sex sex toy toy is is hollow hollow for for housing housing the the electronics, electronics, battery battery and and the the vibration vibration motor. motor. After After modelling, modelling, wewe used used Cura Cura 14.07, 14.07, Ultimaker, Ultimaker Geldermalsen,, Geldermalsen, Netherlands Netherlands, a, asoftware software for for slicing slicing the the 3D 3D model model and and generating the g-code file, which is the one used by the 3D printer. We printed the body of the sex toy in ABS plastic using a homemade 3D printer. The dimensions of the sex toy were 35 mm external diameter and 127 mm length, and those dimensions were chosen considering that the sex toy should be small enough to be used in penetration but large enough to be easily handled. The 3D rendered model, the 3D printing process, and the plastic parts assembled of the sex toy are shown in Figure 3. A hand holding the sex toy is shown in Figure 4 for scale.

Robotics 2018, 7, 46 7 of 21 generating the g-code ﬁle, which is the one used by the 3D printer. We printed the body of the sex toy in ABS plastic using a homemade 3D printer. The dimensions of the sex toy were 35 mm external diameter and 127 mm length, and those dimensions were chosen considering that the sex toy should be small enough to be used in penetration but large enough to be easily handled. The 3D rendered model, the 3D printing process, and the plastic parts assembled of the sex toy are shown in Figure3.

RoboticsARobotics hand 20182018 holding,, 7 7,, xx FORFOR the PEER PEER sex REV toyREV IEW isIEW shown in Figure4 for scale. 77 o o f f19 19

FigureFigure 3.3. 3D3D modelmodel ofof thethe sexsex toytoy plasticplastic body,body, 3D3D printingprinting ofof thethe partsparts,, andand thethe plasticplastic bodybody Figure 3. 3D model of the sex toy plastic body, 3D printing of the parts, and the plastic body assembled. assembled.assembled.

Figure 4. User holding the sex toy. Dimensions are 35 mm external diameter and 127 mm length. FigureFigure 4. User 4. User holding holding the the sex sex toy. toy. Dimensions Dimensions are are 35 mm external diameterdiameter and and 127 127 mm mm length. length.

AfterAfter 3D3D printingprinting andand assemblingassembling thethe bodybody ofof thethe sexsex toy,toy, wewe dedesignedsigned the the electronicelectronic circuits.circuits. After 3D printing and assembling the body of the sex toy, we designed the electronic circuits. WeWe usedused anan ArduinoArduino ProPro MiniMini board,board, whichwhich isis connectedconnected toto aann HCHC--0505 BluetoothBluetooth module.module. AsAs wewe We used an Arduino Pro Mini board, which is connected to an HC-05 Bluetooth module. As we designeddesigned thethe sexsex toytoy toto bebe portable,portable, wewe usedused aa TP4056TP4056 battery battery charger charger module module andand a a 340340 mAh mAh 3.7 3.7 VV designed the sex toy to be portable, we used a TP4056 battery charger module and a 340 mAh 3.7 V LipoLipo batterybattery.. TheThe vibration vibration motormotor useusedd inin thisthis prototypeprototype isis aa commercialcommercial oneone commonlycommonly usedused inin Lipo battery. The vibration motor used in this prototype is a commercial one commonly used in gaming gaminggaming controllers,controllers, and and toto drivedrive thisthis motor motor wewe usedused aa boardboard withwith a a switchingswitching transistor transistor circuit. circuit. We We controllers, and to drive this motor we used a board with a switching transistor circuit. We ﬁxed the fixedfixed thethe electronicselectronics modules modules hhousedoused inin aa 3D3D printed printed enclosure enclosure thatthat was was inserted inserted insideinside thethe bodybody ofof electronics modules housed in a 3D printed enclosure that was inserted inside the body of the sex thethe sexsex toy.toy. AA tactiletactile button button was was also also installedinstalled so so thethe useruser cancan changechange betweenbetween thethe prepre--programmedprogrammed toy. A tactile button was also installed so the user can change between the pre-programmed vibration vibrationvibration patternspatterns andand putput thethe sexsex toytoy inin sleepsleep mode.mode. InIn FigureFigure 55,, wewe showshow thethe electronicelectronic modulesmodules patterns and put the sex toy in sleep mode. In Figure5, we show the electronic modules (top and (top(top andand bottombottom view)view) andand itsits wiring,wiring, thethe plasticplastic housinghousing withwith electronicselectronics insideinside,, andand thethe modulesmodules bottom view) and its wiring, the plastic housing with electronics inside, and the modules connected to connectedconnected toto thethe vibrationvibration motormotor andand batterybattery cell.cell. WithWith thisthis setup,setup, thethe sexsex toytoy cancan workwork forfor the vibration motor and battery cell. With this setup, the sex toy can work for approximately 45 min, approximatelyapproximately 45 45 min min,, andand thethe charging charging timetime isis 90 90 minmin.. and the charging time is 90 min.

FigureFigure 5.5. ElectronicElectronic modules modules of of the the Neurodildo Neurodildo (top (top andand bottombottom vi view),ew), thethe electronics electronics housing housing,, and and thethe connections connections with with the the vibration vibration motor motor and and battery. battery.

ForFor thethe pressurepressure sensingsensing function,function, wewe chosenchosen toto useuse twotwo force force--sensitivesensitive resistors resistors (FSR) (FSR) attachedattached toto thethe bodybody ofof thethe sexsex toy.toy. FSRFSR areare sensorssensors that that detect detect physical physical pressure, pressure, squeezing squeezing,, andand weightweight [33]. [33]. ItsIts resistanceresistance decreases decreases whenwhen aa forceforce isis appliedapplied toto itsits surface, surface, andand byby using using aa voltagevoltage dividerdivider circuit,circuit, wewe couldcould measuremeasure a a variationvariation of of anan analoganalog voltagevoltage dependingdepending on on thethe forceforce appliedapplied toto thethe sensors.sensors. InIn FigureFigure 66,, wewe showshow the the NeurodildoNeurodildo with with the the FSR FSR attached attached to to its its body. body.

Robotics 2018, 7, x FOR PEER REV IEW 7 o f 19

Figure 3. 3D model of the sex toy plastic body, 3D printing of the parts, and the plastic body assembled.

Figure 4. User holding the sex toy. Dimensions are 35 mm external diameter and 127 mm length.

After 3D printing and assembling the body of the sex toy, we designed the electronic circuits. We used an Arduino Pro Mini board, which is connected to an HC-05 Bluetooth module. As we designed the sex toy to be portable, we used a TP4056 battery charger module and a 340 mAh 3.7 V Lipo battery. The vibration motor used in this prototype is a commercial one commonly used in gaming controllers, and to drive this motor we used a board with a switching transistor circuit. We fixed the electronics modules housed in a 3D printed enclosure that was inserted inside the body of the sex toy. A tactile button was also installed so the user can change between the pre-programmed vibration patterns and put the sex toy in sleep mode. In Figure 5, we show the electronic modules (top and bottom view) and its wiring, the plastic housing with electronics inside, and the modules Roboticsconnected2018, 7to, 46 the vibration motor and battery cell. With this setup, the sex toy can work8 of for 21 approximately 45 min, and the charging time is 90 min.

Figure 5. Electronic modules of the Neurodildo (top and bottom view), the electronics housing, and Figure 5. Electronic modules of the Neurodildo (top and bottom view), the electronics housing, and the the connections with the vibration motor and battery. connections with the vibration motor and battery.

For the pressure sensing function, we chosen to use two force-sensitive resistors (FSR) attached to theFor body the of pressure the sex sensingtoy. FSR function, are sensors we chosenthat detect to use physical two force-sensitive pressure, squeezing resistors, and (FSR) weight attached [33]. toIts the resistance body of decreases the sex toy. when FSR a are force sensors is applied that detectto its surface, physical and pressure, by using squeezing, a voltage and divider weight circuit, [33]. Itswe resistancecould measure decreases a variation when aof force an analog is applied voltage to its depending surface, and on the by usingforce applied a voltage to dividerthe sensors. circuit, In weFigure could 6, we measure show the a variation Neurodildo of an with analog the FSR voltage attached depending to its body. on the force applied to the sensors. InRobotics Figure 20186,, 7 we, x FOR show PEER the REV Neurodildo IEW with the FSR attached to its body. 8 o f 19

Figure 6. Force-sensitive resistor (FSR) sensors attached to the sex toy plastic body. Figure 6. Force-sensitive resistor (FSR) sensors attached to the sex toy plastic body. In order to protect the sensors, we designed a silicone sleeve that is placed over the plastic body of theIn sex order toy to and protect over thethe sensors, sensors. we We designed made the a siliconenegative sleeve mold thatof a isslightly placed bigger over the version plastic of body the ofbody the of sex the toy sex and toy over using the sensors.plaster of We Paris made and the then negative used moldthe silicone of a slightly casting bigger technique version to of create the body the ofsleeve the sexby toypouring using silicone plaster of in Paris the andspace then between used the the silicone mold castingand the technique original sex to create toy body. the sleeve In this by pouringprototype silicone we did in n theot use space medical between-grade the silicone, mold and so thethis original version sexis not toy suitable body. In for this being prototype in contact we didwith not the use body. medical-grade The process silicone,of making so the this silicone version sleeve is not is suitable represented for being in Figure in contact 7. with the body. The process of making the silicone sleeve is represented in Figure7.

Figure 7. The silicone casting proce ss for creating the sleeve of the sex toy.

Finally, we assembled the sex toy (Figure 8) with the electronics inside, the attached sensors, and glued on the silicone sleeve. The bottom of the sex toy is removable because it is necessary to access the inside of the sex toy to charge the battery. For charging, a smartphone charger and a micro USB cable can be used.

Figure 8. Neurodildo sex toy assembled.

Robotics 2018, 7, x FOR PEER REV IEW 8 o f 19 Robotics 2018, 7, x FOR PEER REV IEW 8 o f 19

Figure 6. Force-sensitive resistor (FSR) sensors attached to the sex toy plastic body. Figure 6. Force-sensitive resistor (FSR) sensors attached to the sex toy plastic body. In order to protect the sensors, we designed a silicone sleeve that is placed over the plastic body of theIn sex order toy to and protect over the the sensors, sensors. we We designed made the a siliconenegative sleeve mold that of a is slightly placed overbigger the version plastic of body the bodyof the of sex the toy sex and toy over using the plaster sensors. of ParisWe made and thenthe negative used the mold silicone of acasting slightly technique bigger version to create of the sleevebody of by the pouring sex toy siliconeusing plaster in the of space Paris between and then the used mold the siliconeand the castingoriginal technique sex toy body. to create In thisthe prototypesleeveRobotics 2018by ,pouringwe7, 46 did n siliconeot use medical in the -spacegrade betweensilicone, sothe this mold version and isthe not or iginalsuitable sex for toy being body. in contactIn9 ofthis 21 withprototype the body. we did The n processot use medical of making-grade the silicone, silicone sleeveso this is version represented is not in suitable Figure for7. being in contact with the body. The process of making the silicone sleeve is represented in Figure 7.

Figure 7. The silicone casting proce ss for creating the sleeve of the sex toy. Figure 7. The silicone casting process for creating the sleeve of the sex toy. Figure 7. The silicone casting proce ss for creating the sleeve of the sex toy. Finally, we assembled the sex toy (Figure 8) with the electronics inside, the attached sensors, and gluedFinally, on the we wesilicone assembled assembled sleeve. the theThe sex sex bottom toy toy (Figure (Figure of the 8) sex8 with) with toy the is the electronicsremovable electronics inside,because inside, the it theattachedis necessary attached sensors to sensors, access, and gluedtheand inside glued on the o onf thesilicone the sex silicone toy sleeve. to sleeve.charge The bottom Thethe battery. bottom of the Forof sex the charging, toy sex is toyremovable a is smartphone removable because becausecharger it is necessary and it is a necessary micro to access USB to cabletheaccess inside can the be insideof used.the sex of the toy sex to toycharge to charge the battery. the battery. For charging, For charging, a smartphone a smartphone charger charger and a and micro a micro USB cableUSB cable can be can used. be used.

Figure 8. Neurodildo sex toy assembled. Figure 8. Neurodildo sex toy assembled. Figure 8. Neurodildo sex toy assembled.

3.3. The BCI—Emotiv EPOC In order to use the Emotiv EPOC, Emotiv, San Francisco, California, USA, an EEG headset with the Neurodildo system, a series of steps are necessary for setting up the hardware and the software. First of all, the electrode sensors must be wetted using a saline solution in order to obtain good contact with the scalp and good signal quality. After that, the sensors need to be mounted in the neuroheadset arms, and the Emotiv USB transceiver is plugged into the computer. The ﬁrst software to be used is the EPOC Control Panel, Emotiv, San Francisco, California, USA, which must be launched, and then the EPOC headset can be adequately placed on the head, following the positioning instructions in the user’s manual. The signal quality for all the sensors should be checked, and if all of them are green, the BCI is ready for use. Next, we should use the Cognitive Suite, in the Control Panel, for training the detection of brain waves and associate them with the user’s conscious intent to perform physical actions, like pushing or pulling an object and the neutral state of mind. The trained actions should be linked with keystroke commands using the Emokey. Inside the Cognitive Suite tab, any of the possible actions (push, pull, roll, etc.) can be associated with a keystroke action, which is set up by choosing the right parameters. The main parameters are the Limit, Trigger Type, Key Hold Time, and Key Trigger Delay time, the former representing the level of Robotics 2018, 7, x FOR PEER REV IEW 9 o f 19

3.3. The BCI—Emotiv EPOC

In order to use the Emot iv EPOC, Emotiv, San Francisco, California, USA, an EEG headset with the Neurodildo system, a series of steps are necessary for setting up the hardware and the software. First of all, the electrode sensors must be wetted using a saline solution in order to obtain good contact with the scalp and good signal quality. After that, the sensors need to be mounted in the neuroheadset arms, and the Emotiv USB transceiver is plugged into the computer. The first software to be used is the EPOC Control Panel, Emotiv, San Francisco, California, USA, which must be launched, and then the EPOC headset can be adequately placed on the head, following the positioning instructions in the user’s manual. The signal quality for all the sensors should be checked, and if all of them are green, the BCI is ready for use. Next, we should use the Cognitive Suite, in the Control Panel, for training the detection of brain waves and associate them with the user’s conscious intent to perform physical actions, like pushing or pulling an object and the neutral state of mind. The trained actions should be linked with keystroke commands using the Emokey . RoboticsInside 2018the ,Cognitive7, 46 Suite tab, any of the possible actions (push, pull, roll, etc.) can be associated10 with of 21 a keystroke action, which is set up by choosing the right parameters. The main parameters are the Limit, Trigger Type, Key Hold Time, and Key Trigger Delay time, the former representing the level focusing,of focusing, for for example, example, that that should should activate activate the the keystroke keystroke in in the the system. system. It It is is also also necessary necessary to to choose choose what keykey will bebe virtuallyvirtually pressed,pressed, and the Key Hold Time parameterparameter deﬁnesdefines the durationduration of the keystroke. It is also possible t too choose if the key will be h heldeld as long the pre-trainedpre-trained patternpattern intensityintensity value isis higher thanthan thethe chosenchosen threshold. In our tests, we set the limitlimit to 0.55 and the hold timetime to 40 ms, achieving good recognition ofof the brain patternspatterns ofof interest. TheThe parameters shouldshould bebe changed every time a trainingtraining session session occurs occurs or or when when another another person person uses uses the the headset. headset.The The CognitiveCognitive SuiteSuite andand Key ConﬁgurationConfiguration windowswindows areare representedrepresented inin FigureFigure9 9,, which which includes includes the the image image of of thethe virtual virtual block block used for brain pattern training.

Figure 9. Cognitive Suite for brain-pattern training and keystroke configuration. Figure 9. Cognitive Suite for brain-pattern training and keystroke conﬁguration. The following step is to launch a python script that we developed and that runs in the background.The following This script step is is to responsible launch a python for measuring script that the we duration developed of the and last that keystroke runs in the in background. the system, Thiswhich script is related is responsible to the intensity for measuring of the recognized the duration brain of pattern, the last keystrokeconverting in this the time system, to a vibration which is relatedintensity to parameter the intensity (Table of the 1), and recognized sending brain this information pattern, converting to the sex this toy timeby Bluetooth. to a vibration The minimum intensity parametervibration intensity, (Table1), andi.e., when sending the this motor information has 1.011 to V, the was sex calibrated toy by Bluetooth. manually The by changing minimum the vibration voltage intensity,value and i.e., obser whenving the the motorminimum has 1.011that could V, was make calibrated the motor manually rotate without by changing draining the voltagemuch current value andfrom observing the battery. the The minimum same python that could script make is responsible the motor for rotate receiving without the drainingpressure muchvalues current from the from sex thetoy battery.and activating The same the pythonArduino script Nano, is which responsible activates for receivingthe e-stim thedevice pressure and causes values the from user’s the muscles sex toy andto contract, activating who the “feels” Arduino the Nano, same whichpressure activates that the the sex e-stim toy is device being and subjected causes. theFigure user’s 10 musclesshows the to contract,Emot iv EPOC who “feels”EEG headset the same [22]. pressure that the sex toy is being subjected. Figure 10 shows the Emotiv EPOC EEG headset [22].

Table 1. Conversion values of the brain-pattern duration (Focusing) to vibration intensity

(motor voltage).

Focusing (Seconds) Value (Bits) Vibration Intensity (%) Motor Voltage (V) 0 0 0 0 1 < t < 3 70 27.34 1.011 3 < t < 5 128 50 1.85 t > 5 255 100 3.7 Robotics 2018, 7, x FOR PEER REV IEW 10 o f 19 Robotics 2018, 7, x FOR PEER REV IEW 10 o f 19 Table 1. Conversion values of the brain-pattern duration (Focusing) to vibration intensity (motor voltage). Table 1. Conversion values of the brain-pattern duration (Focusing) to vibration intensity (motor voltage). Focusing (Seconds) Value (Bits) Vibration Intensity (%) Motor Voltage (V) Focusing 0( Seconds) Value0 ( Bits) Vibration Intensity0 (%) Motor Voltage0 (V) 1 < 0t < 3 700 27.340 1.0110 1 < t < 3 70 27.34 1.011 Robotics 2018, 7, 46 3 < t < 5 128 50 1.85 11 of 21 3 t <5 5 128255 10050 1.853.7 t > 5 255 100 3.7

FigureFigure 10. 10. EmotivEmotiv EPOC EPOC BCI BCI (Brain (Brain-Computer-Computer Interface) Interface) headset.headset. Figure 10. Emotiv EPOC BCI (Brain-Computer Interface) headset. 3.4. Pressure to E-Stim Feedback 3.4. Pressure to E-StimE-Stim Feedback The third part of the Neurodildo system is the e-stim feedback device. The e-stim, or electrical The third part ofof the NeurodildoNeurodildo system isis thethe e-stime-stim feedbackfeedback device.device. The e-stim,e-stim, or electrical muscle stimulation, is a type of physical therapy modality that can treat illness, pain, and be used for muscle stimulation, is is a a type type of of physical physical therapy therapy modality modality that that can can treat treat illness, illness, pain pain,, and and be used be used for muscle healing. By placing electrodes on the skin, an electrical current causes a single muscle or a formuscle muscle healing. healing. By placing By placing electrodes electrodes on the on skin, the skin, an electrical an electrical current current causes causes a single a single muscle muscle or a group of muscles to contract [34]. The e-stim device can vary the amplitude and timing of the orgroup a group of muscles of muscles to contract to contract [34]. [34 The]. The e-stim e-stim device device can can vary vary the the amplitude amplitude and and timing timing of the electrical stimulation, causing different sensations, similar to a vibration motor in contact with the electrical stimulation,stimulation, causing causing different different sensations, sensations, similar similar to ato vibration a vibration motor motor in contact in contact with with the skin. the skin. We’ve chosen to use an e-stim device integrated to the Neurodildo system because we wanted We’veskin. We’ve chosen chosen to use to an use e-stim an e device-stim device integrated integrated to the Neurodildo to the Neurodildo system becausesystem because we wanted we wanted that the that the user, who is controlling the sex toy vibrations using the mind, could receive an additional user,that the who user, is controlling who is controlling the sex toy the vibrations sex toy vibrations using the mind, using could the mind, receive could an additional receive an stimulation additional stimulation beside the visual stimulus, when having virtual sex. besidestimulation the visual beside stimulus, the visual when stimulus, having when virtual having sex. virtual sex. We decided to explore using of the e-stim because the electrodes can be attached to the body of We decided to explore using of the the e-stime-stim becausebecause the electrodes can be attached to the body of the person—for example, one who has SCI—and do not need to be hand-held—as would happen the person—forperson—for example example,, one who has SCI—andSCI—and do notnot need to bebe hand-held—ashand-held—as would happen with a second vibrator. In our system, there is an Arduino Nano board connected to the board of the with aa second vibrator. InIn our system, there is an Arduino NanoNano board connected to the board of the e-stim plugged into a computer through a USB cable. The computer receives the information about e-stime-stim pluggedplugged intointo a a computer computer through through a USBa USB cable. cable. The The computer computer receives receives the the information information about about the the pressure on the sex toy by Bluetooth and activates the Arduino using a Python script. The pressurethe pressure on the on sex the toy sex by toy Bluetooth by Bluetooth and activates and activates the Arduino the Arduino using a Pythonusing a script. Python The script. Arduino, The Arduino, activates the e-stim, which generates an output wave to the electrodes proportional to the activatesArduino, the activates e-stim, the which e-stim generates, which generates an output an wave output to the wave electrodes to the electrodes proportional proportional to the pressure to the pressure applied to the sex toy. Figure 11 shows the e-stim device, its connection to the Arduino, and appliedpressure to applied the sex to toy.the sex Figure toy. 11Figure shows 11 show the e-stims the e device,-stim device, its connection its connection to the to Arduino, the Arduino and, and the the electrodes placed on a skin. electrodesthe electrodes placed placed on a on skin. a skin.

Figure 11. The comme rcial E-stim de vice ; the Arduino Nano connected to the control panel of the Figure 11. The comme rcial E-stim de vice ; the Arduino Nano connected to the control panel of the FigureE-stim; 11.the Theelectrodes commercial placed E-stim on the device; shoulder the of Arduino a user. Nano connected to the control panel of the E-stim; the electrodes placed on the shoulder of a user. E-stim; the electrodes placed on the shoulder of a user. 4. Experimental Results 4. Experimental Results 4. ExperimentalA series of tests Results was performed to technically evaluate our prototype. We tested the parts of the A series of tests was performed to technically evaluate our prototype. We tested the parts of the systemA series(the sex of teststoy, the was BCI performed, and the to e- technicallystim device) evaluate separately our and prototype. integrated. We In tested this thesection, parts we of system (the sex toy, the BCI, and the e-stim device) separately and integrated. In this section, we the system (the sex toy, the BCI, and the e-stim device) separately and integrated. In this section, we present the tests and their most important results, and by this, we demonstrate the working of the Neurodildo prototype. Robotics 2018, 7, x FOR PEER REV IEW 11 o f 19 Robotics 2018, 7, x FOR PEER REV IEW 11 o f 19 presentRobotics 2018 the, 7 tests, 46 and their most important results, and by this, we demonstrate the working 12of ofthe 21 Neurodildopresent the testsprototype. and their most important results, and by this, we demonstrate the working of the Neurodildo prototype. 4.1. Vibration Vibration Patterns and Intensities 4.1. Vibration Patterns and Intensities Depending on the the brain waves pattern captured by the BCI device, the vibration pattern andand intensityintensityDepending can be changed on the brain proportionally waves pattern in the captured sex toy. by We the implementedimplemented BCI device, the the recognition vibration pattern of only oneand pattern,intensity the can one be c correspondingchangedorresponding proportionally to the “push” in the action sex toy. trained We implementedon the Emotiv Emotiv the software software recognition that is of associated only one withpattern, how the long one thecorresponding user can keep to the focused. “push” Our action software trained sends on the the Emotiv vibration software intensity that (bits) is associated data by Bluetooth,with how longwhich the is userconverted converted can keep to to three three focused. different different Our vibration vibrationsoftware sends intensities the vibration (motor(motor voltage): intensity weak, weak, (bits) medium medium, data by, andBluetooth, strong which (Figure is 12). 12converted). To To demonstrate to three different the vibration vibration intensities, intensities we (m placedotor voltage): the sex toy weak, tip inmedium a bowl , filledandﬁlled strong with water,water, (Figure so so 12).we we could Tocould demonstrateshow show the the level levelthe vibration of of the the intensity intensity intensities, as as the the we waves waves placed produced produced the sex by toyby the thetip vibration invibration a bowl in infilledthe the water. withwater. Aswater, As the the vibrationso vi webration could becomes becomesshow the stronger, stronger, level of the the the wavelength intensity wavelength as decreases. the decreases. waves produced by the vibration in the water. As the vibration becomes stronger, the wavelength decreases.

Figure 12. Vibration inte nsities in the water: first is the we ak, second the medium, and third the strong. Figure 12. 12. VibrationVibration intensitiesinte nsities in the water: first ﬁrst is the we weak, ak, second the medium,medium, and third the strong. 4.2. Pressure Sensing Function 4.2. Pressure Sensing Function The Neurodildo sex toy has two force sensors attached to its body, as mentioned in Section 3.2. The Neurodildo sex toy has two force sensors attached to its body, as mentioned in Section 3.2. TheyThe are responsibleNeurodildo forsex sensing toy has the two pressure force sensors when attached the sex toy to isits being body, penetrated as mentioned or rubbed in Section against 3.2. They are responsible for sensing the pressure when the sex toy is being penetrated or rubbed against theThey body. are responsible For evaluating for sensing this function, the pressure we made when two the different sex toy istests being. First, penetrated we measured or rubbed the voltage against the body. For evaluating this function, we made two different tests. First, we measured the voltage variationthe body. causedFor evaluating by pressure this applied function, to weone made of the two sensors different with testsan oscilloscope. First, we measured. Second, we the collected voltage variation caused by pressure applied to one of the sensors with an oscilloscope. Second, we collected thevariation pressure caused values by transmittedpressure applied from tothe one sex of toy the to sensors the computer with an by oscilloscope Bluetooth,. Sandecond, then we we collected plotted the pressure values transmitted from the sex toy to the computer by Bluetooth, and then we plotted thisthe pressure data and values compared transmitted with the from oscilloscope the sex -toymeasured to the computer signal. Figure by Bluetooth, 13 shows andthe screen then we capture plotted of this data and compared with the oscilloscope-measured signal. Figure 13 shows the screen capture of thethis oscilloscope data and compared during thewith first the test. oscilloscope Each oscillation-measured corresponds signal. Figure to the 13 moment shows the that screen the sensor capture was of the oscilloscope during the ﬁrst test. Each oscillation corresponds to the moment that the sensor was pressured,the oscilloscope and the during intensity the first of these test. oscillations Each oscillation is proportional corresponds to the to the force moment applied. that the sensor was pressured, and the intensity of these these oscillations oscillations is is proportional proportional to to the the force force applied. applied.

Figure 13. Voltage oscillation whe n force is applie d to one of the FSR sensors. The x axis is time Figure 13. Voltage oscillation whe n force is applie d to one of the FSR sensors. The x axis is time (500Figure ms/ 13.SquareVoltage Division) oscillation, and the when y axi forces is voltage is applied (1 V/ toSquare one of Division). the FSR sensors. The x axis is time (500 ms/Square Division), and the y axis is voltage (1 V/Square Division). (500 ms/Square Division), and the y axis is voltage (1 V/Square Division). In the second test, we saved a log of the pressure data received from the sex toy and plotted it usingIn the the MATLAB second test, software. we saved The a datalog of was the received pressure and data saved received at the from same the time sex toy the andfirst plott test edwas it In the second test, we saved a log of the pressure data received from the sex toy and plotted it done.using Figurethe MATLAB 14 represent software.s the The received data waspressure received values, and with saved the at y theaxis same corresponding time the first to thetest ADC was using the MATLAB software. The data was received and saved at the same time the ﬁrst test was done. converterdone. Figure values 14 represent (10 bits, ors the 1024 received values), pressure and the values,x axis is with the time the y of axis the correspondingmeasure. Data wasto the sent ADC in Figure 14 represents the received pressure values, with the y axis corresponding to the ADC converter packagesconverter every values 25 (10 ms, bits, and or the 1024 resolution values), wasand 3.23the x mV axi sfor is theeach time ADC of unit.the measure By comparing. Data was Figure sents 13in values (10 bits, or 1024 values), and the x axis is the time of the measure. Data was sent in packages andpackages 14, it isevery clear 25 that ms, the and pressure the resolution data wa wass collected 3.23 mV and for transmitted each ADC unit. correctly. By comparing Figures 13 andevery 14, 25 it ms, is clear and thethat resolution the pressure was data 3.23 wa mVs collected for each ADC and transmitted unit. By comparing correctly. Figures 13 and 14, it is clear that the pressure data was collected and transmitted correctly.

Robotics 2018, 7, 46 13 of 21 Robotics 2018, 7, x FOR PEER REV IEW 12 o f 19 Robotics 2018, 7, x FOR PEER REV IEW 12 o f 19 Robotics 2018, 7, x FOR PEER REV IEW 12 o f 19

Figure 14. Pressure data of one sensor received by Bluetooth. FigureFigure 14. 14. PressurePressure data data of of one one sensor receivedreceived by by Bluetooth. Bluetooth. Figure 14. Pressure data of one sensor received by Bluetooth. For evaluating the functioning of the two sensors at the same time and data transmission, we For evaluating the functioning of the two sensors at the same time and data transmission, we savedFor a log evaluating of the received the functioning packages andof the plotted two sensors a graph, at which the same is represented time and datain Figure transmission, 15. The black we saved a log of the received packages and plotted a graph, which is represented in Figure 15. The black savedline is athe log signal of the the of received the first packages FSR sensor, and and plotted the blue a graph, dashed which line isis represented the second FSR inin Figure sensor. 1515. It. The is shown black line is the signal of the first FSR sensor, and the blue dashed line is the second FSR sensor. It is shown linethat ispressure the signal can of be the sensed first first FSR independently sensor, andand the by blue each dashed sensor line, and is when the second the same FSR sensor.force is Itapplied is shown to that pressure can be sensed independently by each sensor, and when the same force is applied to thatboth pressurepressure sensors, can thecan bedata be sensed sensed representing independently independently the voltage by by each eachvariation sensor, sensor andhas, and whenthe whensame the value samethe same forcefor eachforce is applied sensor. is applied to In both the to both sensors, the data representing the voltage variation has the same value for each sensor. In the sensors,bothfuture, sensors, we the plan data the to representingdata calibrate representing the the pressure voltage the voltage sensors variation variation and has represent the has same the the value same data forvalue not each byfor sensor. ADC each countssensor. In the but future,In the by future, we plan to calibrate the pressure sensors and represent the data not by ADC counts but by wefuture,absolute plan we topressure calibrateplan to orcalibrate the force pressure applied the pressure sensors to the andsensors sex represent toy. and The represent the example data the not of data by the ADC notreceived countsby ADC data but counts bypackages absolute but by is absolute pressure or force applied to the sex toy. The example of the received data packages is pressureabsoluterepresented orpressure force in Figure applied or force 16 toby applied the the sex screen toy.to the The capture sex example toy. of terminalThe of the example received software. of data the The packagesreceived first column data is represented packages is the first inis represented in Figure 16 by the screen capture of terminal software. The first column is the first Figurerepresentedsensor, 16 the by second in the Figure screen column 16 capture byis the the second of screen terminal sensor capture software., and of the terminal The third first is software. a column value representing isThe the first first column sensor, the intensity theis the second of first the sensor, the second column is the second sensor, and the third is a value representing the intensity of the columnsensor,pressure the is applied the second second to column both sensor, sensors. is the and second theThis third value sensor is is a value,used and thefor representing controllingthird is a value the the intensity representingintensity of of the the the pressure e- intensitystim device. applied of the pressure applied to both sensors. This value is used for controlling the intensity of the e-stim device. topressure both sensors. applied This to both value sensors. is used This for value controlling is used the for intensity controlling of the the e-stim intensity device. of the e-stim device.

Figure 15. Pressure data applied to the two sensors attached to the sex toy. FigureFigure 15. 15. Pressure data applied to the two sensors attached to the sex toy. Figure 15. PressurePressure data data applied applied to to the the two two sensors sensors attached to to the the sex sex toy. toy.

Figure 16. Pressure data from the sex toy, received by the computer using the terminal software. Figure 16. Pressure data from the sex toy, received by the computer using the terminal software. Figure 16. Pressure data from the sex toy, received by the computer using the terminal software. Figure 16. Pressure data from the sex toy, received by the computer using the terminal software. 4.3. BCI—Emotiv Test 4.3. BCI—Emotiv Test 4.3. BCI—Emotiv Test The Emotiv Epoc headset is responsible for measuring the brain waves and detecting the pre-trained The Emotiv Epoc headset is responsible for measuring the brain waves and detecting the pre-trained patternThe associated Emotiv Epoc with headset the brain is responsiblewaves. In our for system, measuring the Emotiv the brain (or waves BCI) data and is detecting received the by pret he- Emotivtrained pattern associated with the brain waves. In our system, the Emotiv (or BCI) data is received by t he Emotiv pattern associated with the brain waves. In our system, the Emotiv (or BCI) data is received by t he Emotiv

Robotics 2018, 7, 46 14 of 21

4.3. BCI—Emotiv Test

RoboticsThe 2018 Emotiv, 7, x FOREpoc PEER REV headset IEW is responsible for measuring the brain waves and detecting13 o the f 19 pre-trainedRobotics 2018, 7 pattern, x FOR PEER associated REV IEW with the brain waves. In our system, the Emotiv (or BCI) data13 o f 19 is Controlreceived Panel by the and Emotiv then passed Control to Panel our python and then script. passed The python to our python script is script. responsible The python for transmit scriptting is theresponsibleControl data Panelabout for andthe transmitting detected then passed pattern the to data our to the aboutpython sex the toy script. detected and Thefor receiving python pattern script tothe the pressure is sex responsible toy values and for data,for receiving transmit which willting the pressurebethe converted data valuesabout and the data, passed detected which to pattern willthe bee-stim convertedto the device. sex toy and The and passed correct for receiving to positioning the e-stim the pressure device.of the Emotiv The values correct Epocdata, positioning headsetwhich will is representedofbe theconverted Emotiv in andEpoc Figure passed headset 17. to isthe represented e-stim device. in Figure The correct 17. positioning of the Emotiv Epoc headset is represented in Figure 17.

Figure 17. User wearing the Emotiv EPOC (BCI) headset. Figure 17. User wearing the Emotiv EPOC (BCI) headset. Figure 17. User wearing the Emotiv EPOC (BCI) headset. In order to debugging our python script and test the Neurodildo system, we used software calledIn Emotiv orderorder to toXavier debugging debugging Composer our our python , pythonEmot script iv ,script San and Francisco, and test test the Neurodildothe CA Neurodil, USA, system,whichdo system, is we capable used we software usedof simulating software called differentEmotivcalled Emotiv Xavier brain patternsXavier Composer, Composer and Emotiv, intensities,, Emot San the Francisco, iv same, San wayFrancisco, CA, that USA, the CA BCI which, USA,headset is which capable would is ofdetectcapable simulating them of (Figure simulating different 18). braindifferent patterns brain andpatterns intensities, and intensities, the same the way same that way the that BCI the headset BCI headset would would detect detect them them (Figure (Figure 18). 18).

Figure 18. The software set responsible for collecting the brain patterns and sending them to the sex toy. Figure 18. The software set responsible for collecting the brain patterns and sending them to the sex toy. Figure 18. The software set responsible for collecting the brain patterns and sending them to the sex toy. The black window in Figure 18 is the output of our python script. This window displays the brain patternThe detected black window or simulated, in Figure w hich 18 is in the this output case isof the our “push python” pattern. script. T Forhis windoweach received displays pattern, the brain the The black window in Figure 18 is the output of our python script. This window displays the correspondingpattern detected intensity or simulated, is also receivedw hich in, which this case is a is value the “push ranging” pattern. from 0.0 For to 1.0. each The received pattern’s pattern, intensity the brain pattern detected or simulated, which in this case is the “push” pattern. For each received pattern, iscorresponding the value that intensity our python is also script received sends ,to which the sex is atoy value, and ranging it converts from it to0.0 vibration to 1.0. The intensities. pattern’s In intensity Figure the corresponding intensity is also received, which is a value ranging from 0.0 to 1.0. The pattern’s 18,is the the value first received that our intensitypython script is 0.45 sends approximately, to the sex toy the, and second it converts is 0.15, itand to vibrationthe last is intensities. 1.0. In Figure 18, the first received intensity is 0.45 approximately, the second is 0.15, and the last is 1.0. 4.4. The E-Stim Test 4.4. The E-Stim Test The last part of the Neurodildo system is the e-stim device, which is a commercial TENS equipmentThe last driven part byof anthe Arduino Neurodildo circuit system and connectedis the e-stim to a device, computer which by USBis a cable.commercial Our python TENS scriptequipment has the driven function by ofan integratingArduino circuit the system, and connected and it sends to athe computer pressure byintensity USB cable. data toOur the python e-stim device,script has which the function varies the of pattern integrating of muscles the system, stimulation. and it sends The voltage the pressure of the intensity electrodes data attached to the eto-stim the device, which varies the pattern of muscles stimulation. The voltage of the electrodes attached to the

Robotics 2018, 7, 46 15 of 21 intensity is the value that our python script sends to the sex toy, and it converts it to vibration intensities. In Figure 18, the ﬁrst received intensity is 0.45 approximately, the second is 0.15, and the last is 1.0.

4.4. The E-Stim Test The last part of the Neurodildo system is the e-stim device, which is a commercial TENS equipmentRobotics 2018, driven7, x FORby PEER an REV Arduino IEW circuit and connected to a computer by USB cable. Our python14 script o f 19 has the function of integrating the system, and it sends the pressure intensity data to the e-stim device, whichskin can varies change the patternits intensity of muscles and frequency, stimulation. and The different voltage patterns of the electrodes cause different attached sensations to the skin in canthe changemuscles. its The intensity idea of andthe frequency,e-stim device and is differentto provide patterns a feedback cause response different in sensations the user wearing in the muscles. the BCI Theheadset idea that of the correspond e-stim devices to isthe to providepressure a being feedback appl responseied to the in thesex usertoy by wearing the second the BCI user headset. We thatmeasured corresponds two different to the pressurepatterns beingof muscle applied stimulation to the sex with toy an by oscilloscope the second user.connected We measured to the e-stim two differentcircuit (Figure patterns 19). of muscle stimulation with an oscilloscope connected to the e-stim circuit (Figure 19).

Figure 19. Two different patterns of the e-stim muscle stimulation: the first is we aker and continuous; Figure 19. Two different patterns of the e-stim muscle stimulation: the ﬁrst is weaker and continuous; the se cond is stronger and with faste r oscillation. the second is stronger and with faster oscillation.

5. Discussion 5. Discussion

5.1. Evaluation of the Neurodildo FirstFirst Version PrototypePrototype The design design process process of of the the first first versio versionn of the of Neurodildo the Neurodildo produced produced a working a working prototype, prototype, which whichfulfilled fulfilled all the functions all the functions that were thatinitially were proposed. initially During proposed. the experimental During the experimentaltests, we evaluate tests,d wewhat evaluated functions what worked functions better worked and the better limitations and the of limitations the prototype, of the including prototype, what including should what be shouldimprov beed in improved the future. in theAt this future. stage At of this the stage project, of theno clinical project, tests no clinical were made tests because were made a partnership because a partnershipwith a hospital with must a hospital be carried must out be and carried an ethical out and approval an ethical must approval be obtained must be in obtained order to inwork order with to workpatients with with patients disabilities. with disabilities. The parts ofof the prototypeprototype werewere firstfirst testedtested separatelyseparately fromfrom the otherother parts,parts, e.g.,e.g., the the vibrationvibration patterns independentlyindependently fromfrom thethe BCIBCI headset,headset, and the pressure sensorsensor independentlyindependently fromfrom the e-stime-stim device. All parts worked correctly,correctly, and and afterafter thesethese tests,tests, thethe systemsystem couldcould bebe integrated andand evaluatedevaluated completely. After setting up the BCI headset, headset, the sex toy was turnedturned on,on, paired withwith thethe computercomputer (the(the samesame one runningrunning thethe BCIBCI software software andand connectedconnected toto thethe e-stime-stim controllercontroller module),module), and and the electrodes of the the e e-stim-stim were were attached attached to to any any par partt of of the the body body (for (for example, example, the the right right shoulder). shoulder). By Byfocusing focusing in a in pre a pre-trained-trained action, action, the the user user could could remotely remotely control control the the intensity intensity of of the the sex sex toy vibration inin a range of four intensities (off,(off, weak, medium medium,, and strong). OnOn the sex toy side, the pressure againstagainst itsits surfacesurface caused caused a a proportional proportional intensity intensity stimulation stimulation in the in the part part of the of bodythe body where where the electrodes the electrodes were attached.were attached. The more The more the sex the toy sex is toy pressed, is pressed, the more the more the muscles the muscles are electrically are electrically stimulated, stimulated, and thisand connectionthis connection is also is also wireless wireless (by Bluetooth). (by Bluetooth). During all the tests, the system worked correctly asas longlong as the batteries ofof the sex toy andand the BCI headset had enough energy. One limitation thatthat wewe verifiedverified is the brain signalsignal quality reduction that occurred because because of of changes changes in in the the position position of of the the BCI BCI headset headset during during usage usage or the or the drying drying of the of thesaline saline solution, solution, which which is used is used for for wetting wetting the the BCI BCI electrodes electrodes and and to to increase increase their their conductance. Recognition of the brain patternspatterns (focus)(focus) was affected by the aforementioned limitations butbut alsoalso by the inherent hardware and software characteristics of the consumer-grade BCI headset (Emotiv EPOC) that we decided to use in this prototype. The silicone sleeve used in this prototype, as mentioned before, has not medical grade, and it could not be in contact with sensitive or internal parts of the body. The reason for not using medical- grade silicone at this stage of the research was because we had readily available the basic silicone rubber for prototyping, which costs six times less than the medical version, and we would not clinically test the prototype. For the next stage, we will improve the design of the silicone sleeve for covering the entire plastic body of the sex toy and use appropriate material to be in contact with the body, so we can conduct the clinical tests safely. Battery consumption is also a limitation, keeping in mind that the Neurodildo has the possibility of becoming a product. The sex toy, when kept in sleep mode, discharged in less than one week. The electronic modules were not optimized to this project,

Robotics 2018, 7, 46 16 of 21 the inherent hardware and software characteristics of the consumer-grade BCI headset (Emotiv EPOC) that we decided to use in this prototype. The silicone sleeve used in this prototype, as mentioned before, has not medical grade, and it could not be in contact with sensitive or internal parts of the body. The reason for not using medical-grade silicone at this stage of the research was because we had readily available the basic silicone rubber for prototyping, which costs six times less than the medical version, and we would not clinically test the prototype. For the next stage, we will improve the design of the silicone sleeve for covering the entire plastic body of the sex toy and use appropriate material to be in contact with the body, so we can conduct the clinical tests safely. Battery consumption is also a limitation, keeping in mind that the Neurodildo has the possibility of becoming a product. The sex toy, when kept in sleep mode, discharged in less than one week. The electronic modules were not optimized to this project, so improving them would directly affect the size of the sex toy and its ergonomic aspects. As the project is intended to be as hands-free as possible, making the e-stim device able to communicate wirelessly with the other parts of the system is needed.

5.2. User Requirements and the New Design Considering the limitations observed during the development and testing of the Neurodildo, and the fact that transforming a prototype into a valuable product is a complex task, new inputs are necessary for changing the design for a second version. It is indispensable when designing an assistive product that the user requirements and impressions should be taken into account. We can discuss the limitations of the current version of the Neurodildo alongside the user requirements presented for assistive devices [9], since the consumers, i.e., people with physical disabilities, are shared. Table2 presents the factors that consumers consider determining for assistive devices, the limitations of these factors in the Neurodildo prototype, and what can be changed for a second version of our project (Table3).

Table 2. Description of technical limitations of the ﬁrst Neurodildo version and the user requirements.

User Requirements Neurodildo v1 Effectiveness Eventual problems on brain pattern recognition Affordability The consumer grade BCI is expensive Operability Separate software modules and complex BCI setup Dependability Plastic parts are not resistant enough and easily removable Portability Separate hardware modules, computer needed for integrating the system Durability Sex toy is not water proof, battery usage is not optimized Compatibility This version need a computer with Python software installed Flexibility The current design has no ﬂexible options Ease of Maintenance Maintenance wasn’t taken into account in this version Securability No security precautions were taken Learnability The BCI is complex for setting up, no user instructions about the sex toy Personal Acceptance The consumer would need assistance on setting up the system Physical Comfort The BCI exerts constant pressure of the electrodes against the scalp Supplier Repair Does not apply Physical Security Electrical Stimulation may cause undesirable effects, e.g., increase the heart rate Consumer Repair Does not apply Easy of Assembly Does not apply Robotics 2018, 7, 46 17 of 21

Table 3. Examples of design improvements for the second Neurodildo version and the user requirements.

User Requirements Neurodildo v2 Effectiveness Improve design of the BCI and communication Affordability To design our own BCI, with simpliﬁed functions Operability Integrate the software, develop our own pattern recognition and simplify the BCI design using dry electrodes Dependability Better design by changing from 3D printer method to injection molding Portability Embedded software, hardware integration and complexity reduction, add a mobile app for setting up the system Durability Improve battery consumption and charging, make the sex toy waterproof and washable Compatibility Design a cross-platform mobile app for controlling the system Flexibility Different color, sizes, programmed patterns, etc. Ease of Maintenance Make the sex toy washable Securability Encrypted communication between modules, user account Learnability Reduce BCI complexity, accessible tutorials on how to use the sex toy Personal Acceptance Reduce the complexity and making the system more accessible Physical Comfort Reduce the number of electrodes and improve the BCI design Supplier Repair Product warrant and replacement policies Physical Security Using same values for electrical stimulation, to inform the precautions needed regarding the electrodes positioning Consumer Repair Does not apply Easy of Assembly Does not apply

The previous tables presented an overview of the main limitations and actions that should be taken in order to achieve an improved design. We analyzed the user requirements presented in an existing work [9], but we need to consider developing our own methodology for listing the main consumer needs. By applying the Quality Function Deployment (QFD) methodology [35] or Design Thinking techniques, the user requirements can be better characterized for our purposes and a more effective and valuable product can be developed. Reducing the steps for setting up and using the Neurodildo, which were presented in Section 3.1, is an important change to be considered in the next version. People diagnosed within the same physical disability may have different limitations, and these limitations differences become more complex when considering a wide range of existing physical disabilities. Designing a device for assisting all or most of the limitations and medical conditions is a very hard task, if not impossible, and that is the why we have chosen to design a mind-controlled device, considering the premise that besides their physical limitations, people can still use their mental skills.

5.3. Issues Regarding the BCI Technology Even though many technical limitations were observed in our current design, issues regarding the BCI headset, which is responsible for measuring the brain signals, were the majority. Designing our own headset, that would be less complex and would have dedicated features for our tasks, might be a solution for the excessive cost when comparing the consumer grade BCI to the rest of our system (sex toy and e-stim device). Reducing the complexity of setting up the BCI by reducing the number of electrodes and changing to the dry electrodes technology would directly affect the user experience and learnability of the system. However, by deciding to incorporate these changes into our design, we should deal with important trade-offs. Researchers [36,37] already compared the accuracy of detecting brain patterns on a single-channel EEG recording system and a multiple electrodes system. In real-life applications, using a single-channel EEG (or BCI) device presents advantages over standard traditional systems, for example reduced cost, portability, and easier set-up. Traditional systems can do a better job capturing good quality EEG data because the high number of electrodes covering the entire scalp but are usually not a user-friendly and are complex systems with elevated cost and inconvenience. According to another study [38], BCI illiteracy is one of the major problems when applying BCI technology in real-life applications, for example to control other devices, and this problem must be resolved before BCI can be adopted to wide use by the public. BCI illiteracy is related to the high performance variability both between and within subjects. The authors argue that a consumer EEG device is only suitable for a beginner level brain signal measurement and research and usable as Robotics 2018, 7, 46 18 of 21 a control device brain reading only if a person has really no other means of signal input (like in a complete locked-in paralysis state, which is not always the case of people with SCI), otherwise other means of command recognition (blinking, eye tracking, sound, video, etc.) are much more viable.

5.4. Current Usage Scenarios and Future Possibilites Regarding the current sex toy design, we also highlight ﬁve possible scenarios that may happen for users of the Neurodildo. In Table4, we refer to healthy couple member as a person without disabilities and of any gender. In scenario 1, we explore the possibility of a couple in an LDR using the Neurodildo as an option to soften the lack of physical contact. In the second scenario, a person with SCI and locomotion limitations may use the remote-controlled sex toy in his or her relationship without the need to go outside his or her home. In the third scenario, we consider a person with SCI or any other disability that has a limited physical condition and/or has failed to engage in a relationship. This person could contact a sex worker and have virtual sex. In both scenarios 2 and 3, it would be recommended that the person with disability had the help of a carer or a trusted person to set up the Neurodildo, the BCI (EEG) headset, and the e-stim device. Improving the design after evaluating the user requirements will enable other scenarios, for example, making the sex toy more portable might enable a better masturbating experience for the user without being uncomfortable while wearing the hardware of the system (scenarios 4 and 5). Even though the Neurodildo is conﬁgured as a vibrator, which is a sex device mostly used by women, we consider that the prototype can be used by any gender and any sexual orientation, disabled or not.

Table 4. Neurodildo usage scenarios.

Scenario No. User A User B 1 Healthy couple member 1 Healthy couple member 2 2 Couple member with SCI Healthy couple member 3 Person with disability Sex worker 4 Person with disability 1 Person with disability 2 5 Person with disability -

As the system is being developed to achieve maximum effectiveness, portability, and compatibility with other systems, it possible to integrate the Neurodildo with sex robots in the near future [39]. People with and without disabilities, besides other means of interaction, might interact with sex robots by sending commands for sexual actions or any other action that the robot is programmed to do. Another possible interaction is the robot recognizing the emotions of the human, which could be measured and transmitted by the BCI device, and then reacting and learning from the human input. Even though both the BCI and the Sex Robots technology are not sophisticated enough yet, we should consider that this integration and application is real [40], and we must advance in studies related to ethical, moral, and social issues that may affect our future. Are we prepared to live with human-like robots and eventually fall in love and have sex with them? What will the rights of both humans and robots be? Will every human-like robot be intended to have sex? Will the robots be safe and/or helpful for people with disabilities? These and many other questions should be studied before the deployment of this controversial technology.

5.5. Future Work The prototype presented in this paper is the ﬁrst one of a work in progress. There are some aspects that we will improve—for example, by designing our own EEG/BCI headset based on the open-source projects, and this should considerably reduce the price of the ﬁnal product. Another point that should be changed is that the computer will be removed from the system and substituted with an embedded hardware solution capable of processing the EEG signals and connecting to the internet Robotics 2018, 7, 46 19 of 21 by Wi-Fi or Bluetooth and with a smartphone. The design and aesthetics of the sex toy will also be improved. As we used commercial electronic modules, the size of the hardware was limited to the size of all modules and batteries. Building our own electronics board would reduce the size of the sex toy, and we may also add new sensors and actuators for creating new stimulation methods. The physical design of the sex toy will also be changed by taking into account ergonomic aspects for people with or without disabilities and trendy sex toys in the market. We will develop a smartphone app, so the working distance of the Neurodildo can be limitless when having internet access. Finally, we will test the Neurodildo with volunteers (disabled and not) to consider what we should keep and what to change in the next versions.

6. Conclusions In this paper, we presented the Neurodildo by explaining its concept, design process, usage scenarios, and technical evaluation. We also discussed the importance of considering the user requirements when designing an assistive product. The Neurodildo is a sex toy remotely controlled by brain waves, which enables long-distance relationship couples to experience sensations that video calls cannot provide. The Neurodildo might be used by people with disabilities, for example with spinal cord injury, who have physical limitations and usually cannot handle commercial sex toys by themselves. We discussed the limitations of the current prototype and effectiveness of BCI for controlling other devices. We also introduced a discussion on the application of sex robots for people with disabilities and how the Neurodildo could be used for controlling these robots in the future. The importance of the work is the design of an innovative technology that might improve the sexual wellness of people with disabilities and improve their quality of life, enabling more possibilities for interaction with other people.

Author Contributions: Conceptualization, L.M.G. and R.W.; Data curation, L.M.G.; Formal analysis, L.M.G.; Investigation, L.M.G.; Methodology, L.M.G.; Project administration, L.M.G.; Resources, L.M.G. and R.W.; Software, L.M.G.; Supervision, L.M.G.; Validation, L.M.G. and R.W.; Visualization, L.M.G.; Writing—original draft, L.M.G. Funding: This research received no external funding. Conﬂicts of Interest: The authors declare no conﬂict of interest.

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