electronics Article NewArticle Technique for Posture Identification in SmartNew Technique Prayer Mat for Posture Identification in Smart Prayer Mat Kasman Kasman * and Vasily G. Moshnyaga GraduateKasman SchoolKasman* of Engineering, and Vasily FukuokaG. Moshnyaga University, Fukuoka 814-0180, Japan; [email protected] * Correspondence:Graduate School of [email protected]; Engineering, Fukuoka University, Tel.: +81-92-801-0833 Fukuoka 814‐0180, Japan; vasily@fukuoka‐u.ac.jp Received:* Correspondence: 26 July 2017; [email protected]; Accepted: 21 August 2017; Tel.: +81 Published:‐92‐801‐0833 23 August 2017 Received: 26 July 2017; Accepted: 21 August 2017; Published: 23 August 2017 Abstract: Smart praying mats are essential to help old and forgetful Muslims perform their religious needs.Abstract: Due Smart to the praying binary mats representation are essential ofto help pressure old and sensors forgetful embedded Muslims intoperform the their mat forreligious posture identification,needs. Due to existing the binary smart representation praying systems of pressure either sensors use largeembedded sensing into arrays, the mat thus for posture becoming expensiveidentification, and bulky,existing or smart utilize praying only a limitedsystems number either use of sensors,large sensing minimizing arrays, the thus cost becoming of posture recognitionexpensive and accuracy. bulky, Thisor utilize article only presents a limited a number new technique of sensors, for minimizing detecting humanthe cost posturesof posture and countingrecognition posture accuracy. cycles This by a article smart mat.presents Unlike a new related technique solutions, for thedetecting proposed human technique postures identifies and posturescounting by posture voltage cycles levels by observed a smart mat. from Unlike five sensorsrelated solutions, only. The the technique proposed has technique been implemented identifies inpostures a prototype by voltage smart levels mat and observed experimentally from five sensors evaluated only. by The 30 technique Islam worshipers. has been implemented The results show in thata prototype it provides smart unobtrusive mat and experimentally and robust (100%) evaluated recognition by 30 Islam of all worshipers. six postures The of the results Muslim show praying that cycleit provides and reliable unobtrusive cycle counting. and robust The (100%) implementation recognition is of inexpensive, all six postures easy of to the use Muslim and quite praying helpful cycle and reliable cycle counting. The implementation is inexpensive, easy to use and quite helpful for users. for users. Keywords: smart mat; pressure sensors; sensor systems and applications; assistive living Keywords: smart mat; pressure sensors; sensor systems and applications; assistive living 1. Introduction 1. Introduction PrayingPraying is is a a central central pillar pillar of of thethe Muslim faith; faith; a a mandatory mandatory religious religious ritual ritual performed performed five five times times a daya day at at prescribed prescribed times. times. TheThe ritualritual is quite challenging for for elders elders whose whose attentive attentive and and cognitive cognitive capabilitiescapabilities are are deteriorating deteriorating with age. age. When When praying, praying, a worshiper a worshiper has hasto perform to perform a sequence a sequence of six of sixpostures postures (Figure (Figure 1)1 )called called Rakah Rakah (in (in singular) singular) and and Rakat Rakat (in (in plural). plural). Because Because the the sequence sequence must must be be repeatedrepeated a a number number of of times times while while recitingreciting passages from from the the Quran, Quran, elders elders frequently frequently have have difficulty difficulty rememberingremembering which which cycle is is being being performed. performed. Incomplete Incomplete sequence, sequence, however, however, is not acceptable. is not acceptable. Once Onceforgotten, forgotten, a worshiper a worshiper must must go back go back and and fulfill fulfill an extra an extra sequence sequence to ensure to ensure that that he hehas has done done the the properproper number number of of Rakat. Rakat. (a) (b) (c) (d) (e) (f) FigureFigure 1. 1.The The sequence sequence of of postures postures to complete a a single single Rakah Rakah in in a aprayer: prayer: (a, (ca), cstanding) standing (b) ( bowing;b) bowing; (d,(fd),f prostration;) prostration; (e ()e) sitting. sitting. Electronics 2017, 6, 61; doi:10.3390/electronics6030061 www.mdpi.com/journal/electronics Electronics 2017, 6, 61; doi:10.3390/electronics6030061 www.mdpi.com/journal/electronics Electronics 2017, 6, 61 2 of 13 Furthermore, the number of cycles, which must be repeated by a worshiper in a pray, varies according to the time of day as well as the day. For example, two Rakat must be performed at dawn prayer, four at each prayer at noon, afternoon and evening, and three at sunset prayer. Old and forgetful people have problems not only remembering how many ritual cycles have to be performed in a prayer but also losing track of the cycles that they have already completed [1]. Although Muslims with severe mental illness or intellectual disability are allowed to be exempted from praying, those with mild and moderate cognitive impairment are not. The options they currently have are quite limited: either to perform in a congregation following the leader or ask someone to inform them which Rakah is currently performed. Elders with cognitive impairment usually practice their rituals at home. They live independently and frequently do not have someone close to ask. At the same time, those who can usually hesitate being a burden to others and showing their cognitive problems, and may eventually lead to bad mood, depression, more extensive cognitive decay, and a stronger association with dementia [2]. Therefore, information and communication technologies capable of assisting forgetful Muslims in praying are important. In this article, we present a new technique for automatic sensing and recognition of Rakat postures by using a smart mat. 2. Related Research Over the years, various technologies have been proposed to help Muslims with prayers and Rakat counting. Google Play and Apple Store nowadays contain a number of software applications which can automatically count the number of Rakat on mobile devices (smartphones or tablet PC) with embedded accelerometers. In order to use the applications, a worshiper must possess a proper device in addition to a prayer mat (which is not always the case for old and forgetful people), and also be within the area of Global System for Mobile Communications (GSM) or Wifi coverage in order to access the application server. Therefore, research efforts have been concentrated on incorporating Rakat counting electronics into the prayer mat itself. Khatri [3] proposed the use of a solar-powered electrical switch pad and liquid crystal display (LCD) operable by a forehead of a worshipper when he or she prostrates on the mat. Faouaz [4] also used LCD with a switch, built in the prayer mat, with the difference that the switch is turned on and off by the user. Abdelmohsen [5] advocated placing a so-called “pressurable plate” under an ordinary mat to detect a prostration posture anytime the user’s forehead touches the mat, and incrementing the Rakat counter on display by every even prostration posture. Arrar [6] developed a portable cycle counter based on IR sensors embedded into the prayer rug. Kantarceken [7] presented a prayer assistance device with built-in camera, infra-red sensors, microphones, Bluetooth and acoustic transducers for detecting physical gestures and spoken words of a prayer. Ismail et al. [8] used pressure sensors embedded in the mat under the forehead area to detect the prostration posture. When a second prostration is recognized, the counter is incremented, and its value is displayed on an MP3 player and replayed as an audible cue. Despite differences in implementation, all of these smart prayer mats have several features in common. Namely, they differentiate human postures by patterns of binary signals (0 and 1) generated from switches or pressure sensors embedded into the mat. The sensors operate locally while the postures span the entire area of the prayer mat. Therefore, the devices either employ a large number of sensors distributed over the mat, as shown in Figure2a, in order to improve the detection accuracy on expense of cost (e.g., [6,8]), or use a few sensors placed under the forehead (see Figure2b) to detect the prostration posture only (e.g., [4,5,7]). These cost-oriented solutions do not take into account the other postures of the Rakah sequence and thus might increment the counter when the user skips a posture or makes two prostrations consequently; which is unacceptable. Besides, to our knowledge, none of the existing prayer mats proposed so far can differentiate the standing posture from the bowing posture, thus impeding the correct posture recognition. Electronics 2017, 6, 61 3 of 13 Electronics 2017, 6, 61 3 of 13 (a) (b) Figure 2. Distribution of pressure sensor in existing smart mats: (a) distributed over the mat area; (b) Figure 2. Distribution of pressure sensor in existing smart mats: (a) distributed over the mat area; (localizedb) localized in the in theforehead forehead area. area. It should be noted that research on smart mats/carpets capable of recognizing human postures and Itanalyzing should be the noted human that research gait has on intensified smart mats/carpets recently, capable especially of recognizing for health human‐care and postures medical and analyzingapplications. the Middleton, human gait et has al. intensified [9] developed recently, a gate especially‐recognition for health-care “floor sensor” and medicalthat had applications. 1536 small Middleton et al. [9] developed a gate-recognition “floor sensor” that had 1536 small sensing elements sensing elements arranged in a 3 × 0.5 m2 rectangular strip with an individual sensor area of 3 cm2. × 2 2 arrangedAud et al. in[10] a presented 3 0.5 m a rectangularfall‐detecting strip smart with carpet an individual built from an sensor array area of signal of 3 cm‐scavenging. Aud et sensors al.