Animatronic Wireless Hand

ANIMATRONIC WIRELESS HAND

A PROJECT REPORT

Submitted by

J. JANET M. KAVITHA R. KIRAN CHANDER

in partial fulfillment for the award of the degree of

BACHELOR OF ENGINEERING IN ELECTRICAL AND ELECTRONICS ENGINEERING

EASWARI ENGINEERING COLLEGE, CHENNAI-89 ANNA UNIVERSITY: CHENNAI-600 025

APRIL 2019

ANNA UNIVERSITY: CHENNAI 600 025

BONAFIDE CERTIFICATE

Certified that this project report “ANIMATRONIC

WIRELESS HAND” is the bonafide work of “J.JANET

(310615105030), M.KAVITHA (310615105033) and R.KIRAN

CHANDER (310615105035)” who carried out the project work under my supervision.

SIGNATURE SIGNATURE

Dr.E.KALIAPPAN,M.Tech., Ph.D., Ms.B.PONKARTHIKA,M.E., HEAD OF THE DEPARTMENT SUPERVISOR ASSISTANT PROFESSOR DEPARTMENT OF ELECTRICAL AND DEPARTMENT OF ELECRICAL AND ELECTRONICS ENGINEERING ELECTRONICS ENGINEERING EASWARI ENGINEERING COLLEGE EASWARI ENGINEERING COLLEGE RAMAPURAM - 600089 RAMAPURAM – 600089

Submitted for the University examination held for project work at Easwari Engineering College on ………………………

INTERNAL EXAMINER EXTERNAL EXAMINER

iii

ACKNOWLEDGEMENT

We would like to express our sincere thanks to our respected chairman, Dr. R. SHIVAKUMAR, M.D., Ph.D., for providing us with requisite infrastructure throughout the course. We would like to express our sincere thanks to our beloved Principal Dr. K. KATHIRAVAN, M.Tech., Ph.D., for his encouragement. We are highly indebted to the Department of Electrical and Electronics Engineering for providing all the facilities for the successful completion of the project. With a deep sense of gratitude, we would like to sincerely thank our Head of the Department Dr.E.KALIAPPAN, M.Tech., Ph.D., for his constant support, encouragement and valuable guidance for our project work. We are extremely grateful to our project supervisor Ms.B.PONKARTHIKA M.E., Assistant Professor, Department of Electrical and Electronics Engineering for her consent guidance, suggestions and kind help in bringing out this project within scheduled time frame. We would like to thank our project coordinator Dr.E.KALIAPPAN, M.Tech., Ph.D., Head of the Department, Department of Electrical and Electronics Engineering for his valuable suggestions and encouragement. We would like to thank all our Parents, Teaching and Non- Teaching staff for their kind co-operation throughout this project work.

J.JANET (31061505030)

M.KAVITHA (310615105033)

R.KIRAN CHANDER (310615105035) iv

ABSTRACT

Amputees face several problems such as phantom pain, surgical complications and skin problems with the use of an artificial hand that cannot be used to perform any operation. In order, to enhance the lives of the physically challenged, the field of animatronics has been a long way from matching the grasping and manipulation capability of their human counterparts. There have been several models designed to help the amputees but are incredibly expensive. To overcome this limitation in order to enhance the comfort of a common man, this project has been developed through changes in the design, fabrication and an alternate means of wireless communication. The movement of the animatronic hand is actuated by the gestures of the normal hand detected by means of a sensitized glove containing flex sensors. The data obtained through this process is transferred to the bionic arm to carry out the pre-programmed action. Thus, the lives of the physically challenged can be enhanced with increased comfort and making them feel independent by utilizing this product to carrying out daily activities.

In the future, this project can be extended to increased number of activities and a different control mechanism. v

TABLE OF CONTENT

CHAPTER NO. TITLE PAGE NO.

ABSTRACT iv LIST OF TABLES viii LIST OF FIGURES ix LIST OF ABBREVIATIONS xi

1 INTRODUCTION 1 1.1 INTRODUCTION 1 1.1.1 Basic Structure and Working of Human Hand 1 1.1.2 Palm 2 1.1.3 Fingers 2 1.2 PROBLEMS FACED BY AMPUTEES 3 1.3 TIMELINE IN PROSTHETICS 5 1.4 ANIMATRONICS 7 1.4.1 Basic Concepts 7 1.4.2 Components of an Animatronic Structure 8 1.4.3 Control Mechanisms 10 1.5 OBJECTIVE OF THE PROJECT 10 1.6 CONCLUSION 11

CHAPTER NO. TITLE PAGE NO.

2 LITERATURE SURVEY 12 2.1 INTRODUCTION 12 2.2 LITERATURE SURVEY FROM REFERENCE PAPERS 12 2.3 SUMMARY 22

3 PROPOSED ANIMATRONIC WIRELESS SYSTEM 23 3.1 PROPOSED SYSTEM DESIGN 23 3.2 HARDWARE DESCRIPTION 24 3.2.1 Flex Sensor 24 3.2.2 Servo Motors 28 3.2.3 Arduino Board 30 3.2.3.1 Technical specifications 30 3.2.3.2 Pins 31 3.2.3.2.1 General pins 31 3.2.3.2.2 Special pin functions 32 3.2.3.3 Communication 32 3.2.3.4 Automatic (Software) reset 33 3.2.4 Bluetooth Module- HC 05 34 3.2.4.1 Introduction 34 3.2.4.2 Pins 34 3.2.4.3 Command mode 36 3.2.5 9V Battery 37 3.2.6 Power Bank 38 3.2.6.1 Power Bank Types 39 vii

CHAPTER NO. TITLE PAGE NO.

3.2.6.2 Power Bank Lifetime 40 3.3 SOFTWARE 40 3.3.1 pinMode() Function 42 3.3.2 digitalWrite() Function 42 3.3.3 analogRead() Function 43 3.4 WORKING 43 3.5 ADVANTAGES OF PROPOSED SYSTEM 3.6 CONCLUSION 44

4 RESULT AND OBSERVATION 46 4.1 3D PRINTED HAND 46 4.2 CONTROL MECHANISM 47

5 CONCLUSION AND FUTURE SCOPE 49 5.1 CONCLUSION 49 5.2 FUTURE SCOPE 49

6 REFERENCES 51

viii

LIST OF TABLES

TABLE NO TITLE PAGE NO

2.1 Postures and its error percentage 1 7 3.1 AT Commands 36

LIST OF FIGURES

FIGURE NO. TITLE PAGE NO.

1.1 Anatomy of human hand 3 1.2 Types of artificial limbs 5 1.3 Timeline of improvement in prosthetics 7 1.4 Animatronic Dragon Kronos 8 1.5 Pnuematic actuators 9 2.1 Assembled jaw mechanism 13 2.2 Rest and flexion movement of the assembled mechanism 14 2.3 Animatronic hand with RF receiver 15 2.4 Module developed with steel caps 16 2.5 Operation using both LM and SG 18 2.6 Gripper in position, downward movement and circular movement of the robotic system. 19 2.7 Simulation of the operation of the animatronic hand 20 2.8 Experimental set-up incorporating EMG Sensors 22 3.1 Block diagram 23 3.2 Flex sensor 25 3.3 Variation in resistance according to the bend 25

FIGURE NO. TITLE PAGE NO.

3.4 Typical voltage divider circuit 26 3.5 Inserting flex sensor in voltage divider circuit 27 3.6 2D model of flex sensor 28 3.7 Micro servo 9G 29 3.8 Arduino Uno pin configuration 33 3.9 Bluetooth HC-05 35 3.1 9V Battery 38 3.11 9V Battery clip 38 3.12 Power bank 39 4.1 Animatronic 3D printed hand with Bluetooth module HC-05 47 4.2 Control glove with HC-05 Bluetooth Module 48

LIST OF ABBREVIATIONS

3DUI 3D User Interfaces OLE Optical linear encoder DC Direct Current GND Ground IOREF Input Output Reference RF Radio Frequency WPAN Wireless Personal Area Network LED Light Emitting Diode LCD Liquid Crystal Display

CHAPTER 1

INTRODUCTION

1.1 INTRODUCTION

1.1.1 Basic Structure and Working of Hand

The hand consists of palm and fingers, the movements of which are controlled by muscles both in the forearm (extrinsic muscles) and the muscles within the hand itself (intrinsic muscles). The movements of the hand as described in the anatomical terms are as follows,

x Flexion : A bending movement by means of which the angle between the two parts decreases. Eg. Flexing fingers while clenching the fist.

x Extension : A straightening movement by means of which the angle increases between the two parts. Eg. Stretching out of fingers. It can be understood that both flexion and extension are two opposite.

x Abduction : A motion that results in a structure being pulled away from the middle. Eg. Spreading out of fingers.

x Adduction: A motion that results in a structure being drwn towards the middle finger. Eg. Closing of fingers.

1.1.2 Palm

The palm of the hand is formed by five metacarpal bones that are an extension from the wrist. There bones are numbered one to five from the thumb to the little finger. The metacarpals come into contact with each other on their sides. Their bulging heads come into contact with the bottom heads of the fingers. These heads can be seen as knuckles with the action of clenching of the fist.

The metacarpal associated with the thumb, numbered as metacarpal 1 is the shortest and most mobile. A special joint known as saddle joint is present between metacarpal 1 and the wrist enabling the tips of the fingers to touch, an action known as opposition.

1.1.3 Fingers

The fingers are numbered from one to five beginning with the thumb which is also known as pollax. The phalanges are the miniature long bones in the fingers. Except the thumb, the each finger has three phalanges as follows,

x Distal bone – The bone located at the tip of the finger.

x Middle and proximal – the bone located at the base of the finger.

As mentioned above, the thumb does not have the middle phalange giving a total of 14 phalanges in each hand. Figure 1.1

3 displayed below provides a clear understanding of the location of each bone.

Figure 1.1 Anatomy of human hand

1.2 PROBLEMS FACED BY AMPUTEES:

People can lose a part or an entire limb for various reasons such as problems with blood circulation, injuries, cancer, birth defects and so on. Amputees thus face a lot of problems both physically and mentally as a result of loss of limb.

In the case of a standard amputation, the cut end of the bone suffers from avascular necrosis. If, as is customary, no weight-bearing is provided along the axis of the bone (that is, if the amputee bears his weight on some proximal portion of the skeleton rather than being distributed over the entire surface of the stump), osteoporosis results due to disuse. Proximal joints display thinning of the joint cartilage. Part of

4 the root of the acetabulum becomes sclerotic. Particularly in children, bones proximal to the amputated bone do not develop maximally, and deformities such as the compensatory scoliosis are common.

Another problem faced is the impairment of the circulation in the average amputation stump. The oscillogram readings made in studies showed that there is a reduction in the total amount of blood traversing the stump as compared with the corresponding segment of the intact limb. Thus because of this factor, most of the amputation stunts became cooler when the ambient air was cooled but did not warm appreciably after warming of the trunk and generalised vasodilation.

The venous drainage of the stump suffered even more than the arterial supply. The venous return in the lower extremities, especially when it occurs against gravity, depends to a great extent on the pumping action of the muscles. It was also found that with classical amputation, the muscles were put to little or no use; if partial or total degeneration takes place, they also form an obstruction to proper circulation.

They experience “Phantom pain”, problems due to surgical complications and skin problems with the use of artificial limbs that were developed in order to overcome this problem, artificial. The usage of such artificial limbs as displayed in the Figure 1.2 takes a long time to learn the method of using it. It also does not prove to be of much help to the amputees as the utilization of such artificial limbs does not enable the individual to perform a task with it. It serves merely for the purpose of display and does not perform any operation. As a conclusion, a suitable limb replacement for the amputees has not been developed yet providing both functionality and comfort.

Figure 1.2 Types of artificial limbs

1.3 TIMELINE IN PROSTHETICS

There have been several developments in the field of prosthetics as depicted by the Figure 1.3 .The timeline of the evolution in the field of prosthetics are as follows.

x From 950-710 B.C. - The earliest-known prosthetic toe made from wood and leather. It was found attached to an Egyptian mummy discovered in the 1800s.

x In 600 B.C. - The Greville Chester toe, created by the Egyptians and discovered in 2000 near present-day Luxar was found to be made out of a cartonnage - paper mache material composed of linen, glue and plaster.

x Around 300B.C. - The oldest known prosthetic leg, the Capua leg, was crafted by Romans from bronze and iron along with a wooden core. A replica of the leg is now housed at the Science Museum in London as the original which was housed at the Royal College of Surgeons was destroyed during the World War II.

6 x During the Middle Ages (476-1000) - Peg legs and hand hooks were common for those who could afford them. Knights were fitted with prostheses designed to hold a shield or fit in stirrups though the functionality was not given importance for. It was during this period that an increasing number of prosthetics was constructed by tradesmen. x During the Renaissance (1400s-1800s) - Copper, iron, steel and wood were used as common prosthetic materials. During the American Civil War (1863), the cosmetic rubber hand with fingers that could move was introduced. Following the World War II (1945), prosthetics were made out of wood and leather. While these prosthetics provided several benefits, these were heavy and difficult to keep clean as leather absorbs perspiration. x Around 1970s – 1990s - Plastics, polycarbonates, resins and laminates were introduced as light, easy to clean alternative to leather models. Carbon fibres were also used to make prosthetics light in weight. Synthetic sockets were also custom fitted for each patient to provide an individualised, comfortable and hygienic fit. x From 2000 – 2014 – Prosthetic design has advanced and resulted in specialised prosthetics which gave rise to high performance, light-weight running blades, capable of navigating various terrains and motorised hands controlled by sensors and microprocessors.

Figure 1.3 Timeline of improvement in prosthetics

Thanks to new technologies such as 3D- printing and improvement in materials, prosthetics has come a long way since the first known wooden toe. Currently animatronics is used to solve the problems faced by amputees to provide them a comfortable and independent lifestyle.

1.4 ANIMATRONICS

1.4.1 Basic Concepts

Animatronics is using electronic machines or robots to mimic or animate human gestures. For nearly half a century, animatronic figures have been providing entertainment in the theme park industry by stimulating life-like sounds and animations. These figures thus enhance the storytelling experience by stimulating visual and audio senses in audiences. Animatronics was first introduced into by Walt Disney in the field of entertainment. Within entertainment application, animatronics had to be identified as human partners whose research covers the design and implementation for human identification using a depth camera.

The animatronic dragon, Kronos, was developed by an engineering graduate, Bian Burns. It was custom designed and fabricated for research purposes which sits atop a table that houses electrical and mechanical components. A majority of the motions capabilities are involved with the head and neck which allowed the dragon to watch humans. The depth camera which was mounted behind the dragon gave it field view out in the front. The motion of the dragon included moving jaw, blinking eyes, expanding wings, shifting tail and sound effects. Based on the movements of the individual, the program tracks the human body for actions. This same mechanism has been employed for the control of the prosthetic hand.

Figure 1.4 Animatronic Dragon Kronos

1.4.2 Components of an Animatronic Structure

An animatronics character is built around the internal supporting frame usually made of steel. Attached to these “bones” are the “muscles” which can be manufactured using elastic netting composed of styrene beads. The frame provides support for electrical

9 and mechanical components, as well as provides shape for the outer skin.

Animatronics is typically designed to be as realistic as possible and is thus built similar as to how it would be in real life. The framework of the animatronic character is like a “skeleton”. Joints, motors and actuators act like the muscles in the human body. Connecting all the electrical components together are wires which act like the “nervous system” of the human body.

Pneumatic actuators, as shown in the Figure 1.5 are used for small animatronics as they are not powerful enough for large designs and must be supplemented with hydraulics. To create more realistic movement in large figures, analog system is generally used to give figures a full range of fluid motion. Mimicking the often subtle displays of living creatures is a challenging task when developing animatronics.

Figure 1.5 Pnuematic actuators

Androids, the fusion of animatronics and artificial intelligence, are robots that imitate human behaviour. Robots are being humanized by

10 providing the appearance and behaviour of living beings to machines through several techniques.

1.4.3 Control Mechanisms

There has been several control mechanisms for controlling in animatronics in the past. Several devices are available on the market as suitable user-interfaces for controlling the device, however, affordable 3DUIs (3D User Interfaces) are limited to the kinetic sensor that has been widely spread owing thanks to Microsoft’s videogame consoles. The next development was the birth of Leap-Motion that used three infra-red sensors for tracking movement. Research such as Microsoft’s Sound-waves was conducted for gesture recognition using computer’s microphone with Doppler effect. Washington University came up with Wisee for gesture recognition using unused wireless waves emitted from router. Leap-Motion was the most affordable however; the hand needs to be exactly horizontal with the sensor to sense the movements. In addition, the user interaction was also affected by the lighting conditions. At the later stage flex control was later adopted for practice.

1.5 OBJECTIVE OF THE PROJECT

In this project, the objective is to design, implement and build a low cost wireless animatronic hand specifically designed for the physically challenged. There are several sub-objectives needed to be accomplished in order to successfully achieve our target which are as below:

1. Define, design and construct the structure of the robot hand.

2. Define the grasping mechanism of the robot hand.

3. Define the control mechanism for controlling the animatronic hand.

4. Construct the wireless mechanism for communicating with the animatronic hand.

1.6 CONCLUSION

By the end of this project, an animatronic hand is developed and it can be controlled by means of a sensitised glove wirelessly. The movements of the hand can be detected by means of the flex sensors present in the glove. The data is transferred to the animatronic hand wirelessly. This hand can be used for performing day to day activities.

CHAPTER 2

LITERATURE SURVEY

2.1 INTRODUCTION

Literature Survey consists of various analyses and research made in the field of interest and the results previously published, taking into account the various parameters and extent of the project. It helps in setting a target for the analyses and thus, giving the problem statement.

2.2 LITERATURE SURVEY FROM REFERENCE PAPERS

Ceasar Guerrero-Rincon, Alvaro Uribe-Quevedo, Hernando Leon-Rodriguez and Jong-Oh Park (2014) presented a hand-tracking application whose motion controls different servos on an animatronic hand as shown in the Figure 2.1. This project is focussed on providing a way for integrating an affordable 3DUI (3-Dimensional User Interfaces) as an alternative input controller. Leap-Motion was used to track the flexion/extension of the fingers through infra-red sensors. The hands need to be completely horizontal in respect to the sensor and the pronation or supination does not reach 90 degrees. The system is configured for detecting the fleion/extension for rotating the DC motor axis accordingly. The system comprised of an animatronic jaw which opened and closed according to the motion data. This detection mechanism can detect only the motions of the finger-tips and

13 not the entire finger. Thus, this could lead to unnecessary errors in operation and increase in the error percentage. The model developed is only a jaw mechanism which cannot perform any task.

Figure 2.1 Assembled jaw mechanism

Tejas.C, Tejahwini.V, Shuvankar Dhal and Sirisha.P.S (2017) have proposed a design of the hand involving only three servomotors and RF encoder and decoder as shown in the Figure 2.2. The design was completely made of wood and the program incorporated allows the hand to make three independent gestures only. Coupling was done to distribute the weight evenly and ensure that the entire weight of the robot arm does not fall on the motor shaft. Two extrusions were joined together by means of aluminium support strips on both the sides. The third servo motor was mounted on one of these aluminium strips for elbow movement. This robotic hand was dPesigned as a small-scale model which mimics the configurations of the human hand and does not incorporate any fingers in design.

Figure 2.2 Rest and flexion movement of the assembled mechanism

Agarwal A.D and Chandak M.A (2012) have proposed a design of a hand relatively similar to a large human hand however, consists of only fingers made of plastic tubes as shown in the Figure 2.3. The number of joints and the number of DOF of the robot hand were designed to mimic the movements of the human hand. The robot hand was also designed such that it has an opposable thumb. It consists of a built-in servomotor with its wires and the wires of all the sensors to be located at the back of each finger and palm. The hard- wire used in the commercialized force sensor was changed to a soft-wire so that the external force that arises due to the motion in the hard wire is eliminated. The design incorporates the unwanted use of tactile sensor for movement which increases the system complexity. This design is expensive owing to the unwanted use of tactile sensors.

Figure 2.3 Animatronic hand with RF receiver

Abhiram M.V, Jayanth Kumar H.S, Krishna Prasad M.J, M.S.Mallikarjunaswamy (2016) proposed a Prosthetic Animatronic Hand that made use of Arduino boards, flex sensors and Xbee modules for communication with servo motors that are mechanically linked to the robot hand as shown in the Figure 2.4. The servo motor actuation system is linked to the fingers of the robot hand by means of nylon strings, to move in accordance with the sensed actions of the human hand. This robot hand was also designed for the purpose of mimicking the actions of the human hand. The prosthetic is designed only till the wrist which cannot be utilised by amputees as the common amputation does not involve the loss of limb from wrist. There was also erratic behaviour of the servo motor that resulted from the intermediate change in voltage. The digital count of the Analog to Digital Converter turned out to be inconsistent and varying rapidly due to the higher sensitivity of the flex sensor. This resulted in the unstable functioning of the servo motors. This module cannot be fit into a human hand and is thus incapable of being used in the field of prosthetics. The materials used

16 are also steel tubes and the entire set up is incapable of performing a desired task.

Figure 2.4 Module developed with steel caps

Godwin Ponraj and Hongliang Ren (2018) proposed an alternate method for human finger tracking as shown in the Figure 2.5. The vision based tracking system offers nil or minimum interference to the user and is free from cumbersome wiring allowing the individual to perform the hand motion in the most natural way possible. However, the quality of tracking is greatly affected by the external environmental factors like ambient light, objects in the tracking area with similar colour or shape, etc. There is also the problem of occlusion faced when incorporating the vision based tracking system. On the other hand, the non-vision based tracking system is immune to the above mentioned problems however; they will not provide the exact co-ordinates of the finger tips. They may also need additional hardware which may cause discomfort to the user when used for long. The objective of this project is to exploit the advantages of both methods in order to achieve a

17 superior tracking method. The sensors that were utilised are Leap Motion sensor (vision based tracking) and Flex sensor (non-vision based tracking) combining input from both to produce a single reliable finger tip position data. Kalman filter, a recursive algorithm is used for sensor fusion due to its ability to estimate the auto-covariance values within a source of measurement thus producing a fused state of output from different sensors with minimum co-variance possible. The final output is displayed in a simulated 3D environment as a visual feedback to the user. The values are stored later in a file and used later for analysis and plotting. The following static postures were performed: Sphere formation with three fingers, parallel extension, fixed hook grasp and tip pinch. These postures were selected in order to avoid self-occlusion. The error percentage without and with flex control is illustrated in the tabular column as shown below.

Table 2.1 Postures and its error percentage

Posture Occluded Finger Error LM Sensor Fusion 3 finger Sphere Index 5% <3% formation Middle 10% 4% Parallel Extension Thumb 4% 2%

Fixed hook Thumb 4% <1% grasp(Ok sign) Tip pinch Index 4-10% 1-5% Thumb 4% <3%

It was observed that finger tracking was occluded in various positions and the entire mechanism would work based on guessing the actual finger tip movement by means of previous data and some basic knowledge on the human hand behaviour. In a real time experiment, a three fingered soft body using a shaft to actuate the finger movements was developed. The shafts of the gripper were actuated by means of stepper motors controlled by the computer individually by means of separate motor drivers. It also needs to be noted that the experiments were carried out indoors with no IR sources near the leap motion controller.

Figure 2.5 Operation using both LM and SG

Puja Dhepekar and Yashwant G. Adhav (2016) proposed a wireless controlled robotic system for surgical tool handling mechanism for pick and place operation to overcome the problem of limited helpers in operation theatres as shown in the Figure 2.6. In order to control the position of the sensors, the researchers have developed many searching methods using Optical linear encoder, Strain gauge and Potentiometer. It was found that the drawback while using OLE is that it could operate only for two angles 0 and 90 degrees. The main issue with strain gauges

19 is that it saturates easily under large deflections which is not suitable to control the robot hand. The use of potentiometer will not give exact accuracy for the sudden change in the movement of the hand glove. To provide accurate control of the robot hand, three flex sensors were used: one for pick and place, up and down movement and one for circular movement. The digitalisation of analog signals is done by using micro controller for servo motor operation. The Figure 2.6 shown below shows the three different positions of the robotic system. The wireless signal transmission was performed via Zigbee module. The drawbacks of this system are, it performed only three movements and it could lift only extremely light materials which cannot be used in real-time. The utilisation of Zigbee module leads to complications like knowledge of the system for utilization of the device, not secure, high replacement cost, prone to attack by unauthorised people, low speed, high maintenance cost, low transmission and low network stability. Thus, this method cannot completely be incorporated in real time.

Figure 2.6 Gripper in position, downward movement and circular movement of the robotic system.

Monique Bernice H. Flores, Charles Mholen B. Siloy and Carlos Oppus, Luisito Agustin (2017) proposed a wireless glove controller that detects finger gestures using make-shift flex sensors and a digital accelerometer as shown in the Figure 2.7. A 3D virtual environment was also created for the virtualization of the user’s hand movements detected by the glove controller which also enables the user to control elements inside the virtual environment. The concept of using the accelerometers also was to detect even the hand-tilting movements. In order to reduce the cost, commercial flex sensors were recreated which reduced the cost to around 90% of the cost when commercial flex sensors were used. The concept of Finger Binary System was used for detecting finger gestures involving two states: 0 for relaxed and 1 for flexed. The Binary Coded Decimal (BCD) equivalent was used to refer to each gesture. The gizDuino microcontroller was used to read the data and interpret it. The usage of gizDuino is disadvantageous as it is not very supported, lesser number of pins, has half the program memory as ATMega and involves the modification of the modification of the Arduino AVR Boards. An actual model was not used to study the accuracy and the efficiency of this approach as this was done using simulation.

Figure 2.7 Simulation of the operation of the animatronic hand

Ehab M. Faidallah, Yehia H. Hossameldin, Saber M. Abd Rabbo and Yehia A. El-Mashad (2014) proposed new control mechanism for controlling the robot arm using EMG and flex signals. The flex sensors were incorporated in gloves in both the wrist and elbow to detect movement with no modification from previous works relating to them. The model of the arm used to verify the improvement in the control mechanism is also not novel as shown in the Figure 2.8. The manoeuvre of EMG sensors has the advantage of eliminating the invasive treatment of human arm however; it is unreliable, unstable and requires careful design of signal processing. Moreover, in addition to get good signals from muscle, the type and placement of the sensor is very important. The insertion-type electrode can meaure EMG signals from a specific muscle by sticking it to the muscle directly but it is not preferable to the patients and there is the danger of sick contagion. The surface-type electrode is free from the danger of sick contagion but the placement of these sensors must be optimal that is parallel to the fibres in order to maximize the probability of reading the signal as shown in the Figure 2.8. This position is difficult to determine by an ordinary individual and requires medical assistance. Thus, this mechanism is not user friendly. The necessity of the EMG signal conditioning circuit further complicates the process which comprises of two stages of amplification to amplify the amplitude of the EMG signal, band-pass filter to eliminate noise, precision full-wave rectifier to rectify the EMG signal and fuse protector to protect the circuit from damage.

Figure 2.8 Experimental set-up incorporating EMG sensors

2.3 SUMMARY

This chapter has discussed about the survey points collected from different sources pertaining to this project and has briefed about the working principles and the disadvantages of those previous systems and models. This chapter had taken the idea of the project to a different level and the positives, shortcomings of the works of different people are looked upon and several alternatives are implemented in this work.

CHAPTER 3

PROPOSED ANIMATRONIC WIRELESS SYSTEM

3.1 PROPOSED SYSTEM DESIGN

Figure 3.1 Block diagram

3.2 HARDWARE DESCRPTION

3.2.1 Flex Sensor

Flex sensors as shown in the Figure 3.2 are sensors that change resistance depending on the bend or pressure it is subjected to. These sensors convert the bend into electrical resistance. The resistance value change is such that, more the strain on the sensor, higher the resistance value. The utilization of flex sensors are easy and are several manufacturers who manufacture them in the market.

The datasheet provides instructions to use operational amplifier, if the flex sensor is used as a stand-alone device. Since the Arduino is used, the utilization of OpAmps is eliminates and the circuit is made simple and convenient with only one additional resistor.

Flex sensors are usually available in two sizes. One is 2.2 inch and the other is 4.5 inch. Although the basic function remains the same. They are also divided based on resistance. There are LOW resistance, MEDIUM resistance and HIGH resistance types. Flex sensor is a two terminal device and does not have polarized terminals. Hence, there are no positive or negative terminals in a flex sensor like that of a diode. The P1 terminal of the flex sensor is usually connected to the power source while the P2 terminal is usually connected to the ground.

Figure 3.2 Flex sensor

The features and specifications of flex sensors are as follows:

x Operating voltage : 0 – 5V

x It can operate on low voltages

x Power rating : 0.5W (continuous), 1W (peak)

x Operating temperature : -45 ºC to +80 ºC

x Flat resistance : 25K

x Resistance Tolerance : ±30%

x Bend Resistance Range : 45K to 125K (depending on bend)

Figure 3.3 Variation in resistance according to the bend

As shown in the Figure 3.3 above, when the surface of the flex sensor is linear it, will have its nominal resistance. When it is bent to an angle of 45º, the resistance increases to twice the nominal resistance. So the resistance across the terminals rises linearly with the bent angle. Thus, the flex senor converts the flex angle into a resistance parameter.

For convenience, we convert the resistance parameter into a voltage parameter by means of the voltage divider circuit. A typical voltage divider circuit is as shown in the Figure 3.4.

Figure 3.4 Typical voltage divider circuit

In this resistive network, there are two resistors. One of them is the constant resistance (R1) and the other is the variable resistance (RV1). Vೊ is the voltage at the midpoint of voltage divider circuit and also the output voltage. Vೊ is also the voltage across the variable

27 resistance (RV1). So when the resistance value due to R1 is changed, the output voltage Vೊ also changes. Replacing the variable resistance with that of a flex sensor, the circuit is as shown below.

Figure 3.5 Inserting flex sensor in voltage divider circuit

Here,

9ೊ = Vcc (Rx/(R1+Rx))

Rx – resistance of flex sensor

Thus, when the flex sensor is bent, the resistance increases due to which the drop across the flex sensor. This results in an increase of Vೊ also. This voltage parameter can be fed to the ADC to get the digital value which can be used conveniently.

Figure 3.6 2D model of flex sensor

3.2.2 Servo Motors

Servo motors are DC motors allowing precise control of angular position by means of an error sensing feedback system. It also requires a dedicated controller, most commonly a dedicated module designed particularly for use with servo motors. The speed is usually lowered by gears and they have a revolution cut-off from 90º to 180º and some motors even having 360º. The servo motors do not rotate constantly. Their rotation is limited between fixed angles.

The servo motor is an assemblage of four things: a regular DC motor, a gear reduction unit, a position-sensing device and a control circuit. These motors run at high speed and low torque. The gear and shaft assembly connected to the DC motor lowers the speed sufficiently and produces a higher torque. The position sensor senses the shaft position from its definite position and feeds this information to the control circuit. The control circuit appropriately decodes the from the position sensor. It compares the actual position of the motors with the

29 desired position and controls the direction of rotation of the DC motor to obtain the required position. The servo motors generally require 4.8V to 6V DC supply for operation. The position of the servo motor is controlled by means of Pulse Width Modulation Technique. The width of the pulse applied to the motor is varied and transmitted for a fixed amount of time which thus determines the angular position of the servo motor. For standard servo motors, the gear is normally made of plastic whereas for high power servos, metal gears are utilised.

Servo motors as shown in the Figure 3.7 were chosen for this project as stepper motors require more current exchanges per rotation. The stepper motor design also results in torque degradation at higher speeds and significant heat generation in both motor and drive when operated in constant current mode.

The servo motor resolves the heat generation problem by supplying only the sufficient motor current to move or hold the load. It produces a peak torque several times higher than that of stepper motor. For the purpose of our project, plastic gear servo motors are used.

Figure 3.7 Micro servo 9G

3.2.3 Arduino Board

Arduino Uno is an open source microcontroller board based on ATmnega328Pp microcontroller and was developed by Arduino.cc. The board has 14 digital pins, 6 analog pins and can be programmed with the Arduino IDE through a B type USB cable. The power to the board can be supplied by means of a USB cable or by an external 9V battery though it accepts voltages between 7 and 20 volts. The Uno board is the first board in the series of USB Arduino boards and the reference model for the Arduino platform. The ATmega 328 on the Arduino Uno comes pre-programmed with a boot-loader which enables uploading a new code to the board without the use of an external hardware programmer. The Uno board also differs from the preceding boards in that it does not use the FTDI USB to serial driver chip.

3.2.3.1 Technical Specifications

x Microcontroller: ATmega328P

x Operating voltage: 5V

x Input voltage: 7 to 20V

x Analog input pins: 6

x Digital I/O pins: 14 of which 6 pin provide PWM output.

x Flash memory: 32KB of which 0.5KB is used by bootloader.

x SRAM: 2KB

x EEPROM:1KB

x Clock speed: 16MHz

3.2.3.2 Pins

3.2.3.2.1 General pins

The pin configuration of Arduino Uno is as shown in the Figure 3.8.

x LED: This built-in LED driven by the digital pin 13 is OFF when the pin is LOW and is ON when the pin is HIGH,

x Vin: The input voltage to the Arduino board when using an external power source. The voltage can be accessed through this pin when also supplied by means of a power jack.

x 5V: This pin provides a regulated output voltage of 5V when the board can be supplied power from any means.

x 3.3V: This pin offers 3.3V generated by the on-board regulator.

x GND: These are nothing but ground pins.

x IOREF: This pin provides the voltage reference with which the microcontroller operated. A properly configured shield can read the IOREF pin voltage and select the appropriate power source.

x Reset: This is used to reset the microcontroller.

3.2.3.2.2 Special pin functions

In addition to the above mentioned pins, some pins have specialised functions which are as follows.

x Serial/UART: The pins 0 (Rx) and 1 (Tx) are used to receive and transmit serial data respectively.

x External interrupts: Pins 2 and 3 can be configured to trigger an interrupt on a low value, a rising or falling edge, or a change in value.

x PWM (Pulse Width Modulation): Pins 3, 5, 6, 9, 10 and 11 provides an 8-bit PWM output with the analogWrite() function.

x SPI: Pins 10 (SS), 11 (MOSI), 12 (MISO) and 13 (SCK) support SPI communication using the SPI library.

x TWI/I2C: A4 or SDA pin and A5 or SCL pin supports TWI communication from the Wire library.

x AREF: Analog REFrence provides the reference voltage for the analog inputs.

3.2.3.3 Communication

The Arduino Uno has a number of facilities for communicating with a computer, another Arduino board or other microcontrollers. The ATmega328P provides UART TTL serial communication which is available on the digital pins 0 (Rx) and 1 (Tx). The Arduino IDE includes a serial monitor which allows simple textual

33 data to be sent from one board to another. The Rx and Tx LEDs on the board will flash when data is being transmitted through the USB to serial chip and USB connection to the computer. A Software Serial library allows serial communication on any of the Arduino Uno’s digital pins.

3.2.3.4 Automatic (Software) Reset:

Rather than requiring a physical press of the reset button before an upload of the program onto the board, Arduino Uno is designed in a way that allows it to be rest by the software running on a connected computer.

Arduino Uno has been used for this project as it is inexpensive. One of the major objectives of the project is to make the animatronic hand less expensive in order to be accessible by commoners. The Uno board can run on various operating systems and is less complex. There is no requirement of specialised knowledge in order to operate the device.

Figure 3.8 Arduino Uno pin configuration

3.2.4 Bluetooth Module-HC 05

3.2.4.1 Introduction

Bluetooth is a classic for short-range radio frequency (RF) communication, mainly used to establish wireless personal area network (WPAN). It has a range up to 100 metres depending on the transmitter, receiver, atmosphere, geographic and urban conditions. It is IEEE 802.15.1 standardized protocol, through which one can build PAN. It uses frequency-hopping spread spectrum radio technology to send data over air. It uses serial communication and communicates with the microcontroller using serial port (USART). The module can be used in master-slave configuration and allows all serial enabled devices to communicate with each other using Bluetooth.

3.2.4.2 Pins

Bluetooth has the six pins which are as follows and are shown in the Figure 3.9.

x Key/EN: This pin is used to bring the Bluetooth module in AT commands mode. If this pin is high, this module will work in command mode else, by default it will work in data mode. The default baud rates for HC 05 in command mode and data mode are 38400bps and 9600bps respectively. In data mode, data is exchanged between devices while in command mode AT commands are used to change the setting of HC 05 which are sent to the module serial (USART) port.

x Vcc: A voltage of 5 volts or 3.3 volts are connected to this pin.

x GND: This is the ground pin of the module.

x Txd: This pin is to transmit serial data.

x Rxd: This pin is to receive data serially.

x State: This pin is used to indicate whether the module is connected or not.

Figure 3.9 Bluetooth HC-05

HC-05 has a red LED that indicates the connection status of whether the Bluetooth is connected or not. Before connecting to the HC- 05 module, the red LED blinks continuously in a periodic manner and this blinking slows down when it gets connected to any device. It works on 3.3 volts. A 5V supply voltage can also be connected since there is 5 to 3.3V regulator on-board. Also, the microcontroller can detect 3.3V eliminating the need to shift the transmit level of HC-05 module however, the needs to be a shift in the voltage level from microcontroller to Rx of HC-05 module. Before establishing communication between the devices, they must be paired together first.

3.2.4.3 Command mode

In order to change the settings of HC-05 module, it must be operated in command mode by means of AT commands. For utilization in AT command mode whose default baud rate is 38400bps, the pin “Key” must be connected to HIGH (Vcc).

Table 3.1 AT Commands

COMMAND DESCRIPTION RESPONSE AT Checking communication OK AT+PSWD=XXXX Set password OK e.g. AT+PSWD=4567 AT+NAME=XXXX Set Bluetooth Device OK Name e.g. AT+NAME=MyHC- 05 AT+UART=Baud rate, Change Baud Rate OK stop bit, parity bit e.g. AT+UART=9600,1,0 AT+VERSION? Respond Version no: of +Version: XX OX Bluetooth module e.g. +Version: 2.0 20130107 OK AT+ORGL Send detail of setting done Parameters: device by manufacture type, module mode, serial parameter, passkey, etc.

When devices connect to each other, Bluetooth uses a link which uses optional pre-shared key authentication and algorithms which is strong when used correctly. The strength of Bluetooth security lies in the length and the randomness of the passkey used at the time of the first connection. Also, the previous works related to this project utilised Zigbee and Xbee module for communication which covers a long range and is not required for this application. Thus, Bluetooth is used in order to have a short-range and eliminate the disadvantages of both Zigbee and Xbee.

3.2.5 9V Battery:

The 9V battery, in its most common form was introduced for early transmitter radios. It is rectangular prism in shape with rounded edges and a polarized snap connector at the top as shown in the Figure 3.10. This type is commonly used in walkie-talkies, smoke detectors, etc.

The battery clip, as shown in the Figure 3.11, is plugged onto the standard 9V battery with the device connected to the other end that needs the 9V supply. The connector colour coded in terms of polarity as red and black. They are moulded plastic and hence they won’t tear like cheap clips.

Most 9V alkaline batteries are constructed of 6 individual 1.5V LR61 cells enclosed in a wrapper. These cells are slightly smaller than LR8D425 AAAA cells and can be used in their place for some devices although they are 3.5 mm shorter. The utilisation of this battery is safe and secure. The battery terminals are covered preventing the occurrence

38 of shorts. This 9V battery is used in the project for supplying power to the PCB board in the glove that is supplying power to the flex sensors.

Figure 3.10 9V Battery

Figure 3.11 9V Battery clip

3.2.6 Power Bank

Power banks, as shown in the Figure 3.12 are effective portable chargers which come is a variety of shapes and sizes to suit different people and their needs. The USB cable is utilized as the

39 charging interface. They use circuitry to control power in and power out. They can be charged using the USB charger when power is available and later use this stored power to charge the battery of several devices.

Figure 3.12 Power bank

3.2.6.1 Power Bank Types

There are various types of power banks that can be utilized according to the necessities which are as follows. x Universal or standard power bank:

They are normal power bank portable chargers that can be charged from normal USB sources like USB chargers. x Solar power bank:

They are charged by means of sunlight through photovoltaic panels but only able to trickle-charge the internal battery because the solar cells are relatively small. The charging is generally slow and this power bank can be joined from a USB charger a well.

3.2.6.2 Power Bank Lifetime

There are two main lifetimes associated with power banks which are as follows. x Charge discharge cycles:

The lifetime is normally quoted in terms of the number of discharge cycles it can undergo before the performance falls by a given degree. Some power banks that are cheap may have a life of only 500 or so however, better ones will have a lifetime of many more charge discharge cycles. x Self discharge time:

All batteries have a certain level of self discharge. For rechargeable batteries, a small amount of power is required to keep the circuit alive due to which there is only a finite time within which the battery will remain charged.

Power banks were chosen for the supply of power due to its long life. They are also reliable and their usage ensures continuous power supply without the occurrence of interruptions in the supply. Thus, with the utilization of power banks, smooth and uninterrupted working of the animatronic hand is guaranteed.

3.3 SOFTWARE:

Arduino is an open-source electronics platform which is based on easy to use hardware and software. Arduino boards can be

41 programmed to read inputs from a sensor, finger, button, etc. and turn it into output such as activating a motor, turning on an LED, publishing something online, etc. Thus, the board can be made to do various tasks by sending a set of instructions to the microcontroller on the board. Thus, for this purpose Arduino programming language is used.

The structure of the Arduino program comprises of two main functions: x setup() function:

The setup() function is called when the sketch starts execution. It is basically used to initialise variables, pin modes, etc. This is run only once after every power up or reet operation of the Arduino board. x loop() function:

After the setup() function is executed and the variables are initialised, the loop() function is then executed. The block of statements inside the loop() function is run over and over again, allowing the program to change and respond. Thus, this function is actively used to control the Arduino board.

The pins can be configured as either input or output but are configured as input by default. Input pin make small demands on the circuit being sampled which means they take very little current to switch the input pin from one state to another. These pins are useful for implementing for reading input from sensors. The pins configured as output pins are said to be in a low impedance state which means they

42 can provide substantial amount of current to other circuits. ATmega pins can source or sink up to 40mA of current to other devices/circuits. Running high current devices from the output pins can damage or destroy the output transistors in the pin or damage the entire ATmega chip which results in a “dead pin” in the microcontroller but the remaining chips still function adequately. For this reason, the output pins to other devices must be connected through resistors unless the maximum current drawn from the pins is required for the application.

3.3.1 pinMmode() FUNCTION:

The pins can be configured as input and output by using the pinMode() function.

Syntax: pinMode(pin, mode);

pin – pin number whose mode must be set

value – HIGH or LOW

3.3.2 digitalWrite() Function:

This function is used to write a HIGH or a LOW value to a digital pin. If the pin has been configures as an OUTPUT pin, its voltage will be set to corresponding value: 5V (or 3.3V on 3.3V boards) for HIGH and 0V for LOW. When the pin is configured as an INPUT pin, digitalWrite() will enable (HIGH) or disable (LOW) the internal pull-up on the input pin.

When the pinMode() is not set to OUTPUT and an LED is connected to a pin, the LED will appear dim when digitalWrite(HIGH) is called. Without explicitly setting pinMode(), digitalWrite() will have enabled the internalpull-up resistors which act as a large current-limiting resistor.

Syntax: digitalWrite(pin, value)

pin – pin number whose mode must be set

value – HIGH or LOW

3.3.3 analogRead() Function:

The arduino is capable of detecting whether there is a voltage applied to one of its pins and report it through digitalRead() function. There is a difference between an on/off sensor, which detects the presence of an object and an analog sensor, which detects values that change continuously. The analog values can be read by the function, analogRead(). The function returns a number within the range of 0 – 1023 which represents voltages between 0- 5V.

Syntax: analogRead(pin);

pin – the analog pin number.

3.4 WORKING:

The motions of the human hand is detected by means control glove. This control glove consists of flex sensors affixed to each finger on the glove. These flex sensors produce a change in the resistance

44 depending on the flexion and extension of the fingers. One end of the flex sensor is connected to the analog pins of the arduino board by means of jumper wires. The values are read by the arduino board using the analogRead() function. According to the values read, the arduino board in the animatronic hand is communicated wirelessly through Bluetooth communication and made to perform the specific pre- programmed tasks. The 3D printed hand is actuated by the control glove and the fingers of this hand are moved by means of badminton strings. There is also an LCD monitor indicating the battery level available for operating the arm. Thus, the animatronic hand is successfully operated wirelessly and functions like a prosthetic arm for the amputees thus achieving the goal of this project.

3.5 ADVANTAGES OF THE PROPOSED SYSTEM:

The proposed system has the following advantages which are listed as follows.

x The proposed system is portable and compact. It can be fitted a replacement for the missing limb of the amputees. It can also left on a table or placed on a stand according the needs of the amputee providing comfort which is one of the major objectives of the project.

x This system incorporates the utilisation of Bluetooth which is a novel feature when compared to previous works. This makes the system more secure, faster in speed with high network stability and low power nature. The replacement and the maintenance cost is also lesser.

It also does not require knowledge of the technology incorporated for the utilisation of the system thus making it user friendly.

x The utilisation of flex sensors provides accurate detection of the movements of the hand

x The wireless mechanism eliminates the disadvantages of a wired connection enhancing the comfort provided to the user.

3.6 CONCLUSION:

Thus, the utilization of flex sensor based control proves to be a viable means of accurate control of movements of the animatronic hand. The use of Bluetooth also enables secure and reliable communication. The 3D printed hand can enable the amputee to perform actual tasks with precision.

CHAPTER 4

RESULT AND OBSERVATION

4.1 3D PRINTED HAND

The project with all the hardware components and suitable programming was done and the results were obtained. The 3D printed hand as shown in the Figure 4.1. The various parts of the hand were printed individually by means of a 3D printer. These parts were assembled together by means of adhesive and plastic fibres. The finger movements are realised by means of badminton strings run through the hollow fingers and over the servo motors. The 3D printed hand also has space provided for the insertion of the hand of the amputee. It was able to move smoothly and perform the necessary pre-programmed tasks.

Figure 4.1 Animatronic 3D printed hand with Bluetooth module HC-05

4.2 CONTROL MECHANISM:

The control glove as shown in the Figure 4.2 comprising of the five flex sensors was affixed on the glove by stitching them over the fingers of the glove. The sensors were further secured by means of tape. The wires from the soldered soldered PCB board is connected to the flex sensor and affixed on the glove. The arduino board is also fixed onto the glove together with the Bluetooth module. The readings from the flex sensor were read and the operation of the hand was verified.

Figure 4.2 Control glove with HC-05 Bluetooth module.

CHAPTER 5

CONCLUSION AND FUTURE SCOPE

5.1 CONCLUSION

The objectives of this project have been achieved utilising the flex sensor based control accurately. From the observation that has been made, the 3D printed arm is precise and accurate in movement. The arm has been observed to lift up to a minimum desired weight. The arm is also easy to control and is user-friendly. The animatronic hand developed can be affixed in the place of the missing limb. It can also be placed on a table or a stand depending on the requirements of the user. The hand also performed the pre-programmed daily activities thereby fulfilling the objectives of the project. The wireless communication is also secure enabling reliable operation of the animatronic hand. Thus, the utilisation of this animatronic hand provides comfort and makes the amputees independent.

5.2 FUTURE SCOPE

In future, this product can be upgraded by performing multiple daily activities and not just five. In general, the hand is a very complex part of the human body. The performance of one application may not be sufficient for another. Ultimately, the selection of hand characteristics is a choice between trade-off in complexity, dexterity, weight and control

50 methods. The design can be made for sophisticated to give a more polished look than a skeletal figure whilst improving the performance and improving the motion of the animatronic hand.

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