design of a wearable sensor glove to measure human hand

Design of a wearable sensor glove to measure human hand movement

Dhwani patel1 Sarthak nayak2 and Atluri Venkatkrishna3

Abstract— Generally due to any sort of accident or injury,the movement of hands gradually reduce to a point where thenatural fluency of hand cannot be regained back. So herewireless wearable sensor technique is used which helps indetermining the defect in hand movement. So the purpose ofthe project is to design a sensor that can analyse the movementwhile moving the hand and simultaneously detect the directionof hand movement. The main principle involved in the designingof the sensor is when ever the sensor will undergo a deflectionwhile moving, electrical output will be produced which willbe converted to a certain voltage. an accelerometer will beemployed with the sensor to measure the speed and directionof the hand movement while motion. The accelerometer is anelectromechanical device used to measure acceleration forcesthat might be static like the continuos force of gravity or as inthe case of many mobile devices, dynamic to sense movement orvibrations. The main aim of this project is to detect movementdisorders of aged individuals at an early stage.According tocurrent report the aged individuals from the age group of 60and above faces hand movement disorders. So to curb thisproblem at an early stage a sensor based glove is develop whichwill analyse the motion that should be possess by the age groupof 60 and above by comparing with the normal individuals ofthat age group with the help of medical data.

Keywords : Certain movements, Normal Individuals, MedicalData

I. INTRODUCTION

Movement disorders are clinical syndromes with either anexcess of movement or a paucity of voluntary and invol-untary movements, unrelated to weakness or spasticity.[1]Movement disorders are synonymous with basal ganglia orextrapyramidal diseases.[2] Movement disorders are con-ventionally divided into two major categorieshyperkineticand hypokinetic. Hyperkinetic movement disorders refer todyskinesia, or excessive, often repetitive,involuntary move-ments that intrude upon the normal flow of motor activity.Hypokinetic movement disorders refer to akinesia (lack ofmovement), hypokinesia (reduced amplitude of movements),bradykinesia (slow movement) and rigidity. In primary move-ment disorders, the abnormal movement is the primarymanifestation of the disorder. In secondary movement disor-ders, the abnormal movement is a manifestation of anothersystemic or neurological disorder.[3] A functional movement

1Dhwani Patel, Electronics and Instrumentation Engineering,SRM Institute of Science and Technology ,Potheri ,[email protected]

2Sarthak Nayak,Electronics and Instrumentation Engineering,SRM Institute of Science and Technology ,Potheri ,[email protected]

1AtluriVenkatkrishna, Electronics and Instrumentation Engineering,SRM Institute of Science and Technology ,Potheri ,[email protected]

disorder means that there is abnormal movement or position-ing of part of the body due to the nervous system not workingproperly (but not due to an underlying neurological disease).When an arm or leg shakes uncontrollably. In functionaltremor this is often quite variable. It may even disappearwhen you are distracted but at other times be very disabling.Some people experience jerky types of movements. Thismay be particularly in response to loud noises, certain kindsof lighting or bursts of pain. Some people find that theirhands or feet develop abnormal postures which are hard toovercome. This may be a temporary intermittent problem (aspasm) or may be more chronic (this is usually called fixed /functional dystonia or contracture). Patients with functionaldystonia often have a clenched hand or a twisted foot.[4] Thediagnosis of a functional movement disorder is usually madeby a neurologist. It can be a particularly difficult diagnosis tomake because it requires expert knowledge of the full rangeof movement disorders due to neurological disease, many ofwhich are unusual or even bizarre.It is therefore difficult tosummarise all of the clinical features of functional movementdisorders. They often occur in relation to injury and the onsetcan be sudden.[5]

Gestures are physical movements of different parts of thebody that are expressive and meaningful to human beings.We use different form of gestures to convey informationor to interact with the environment. Hands are one of theprimary means of interacting with external world in ourdaily lives, and they allow us to manipulate and recognizevarious types of tools and objects with high dexterity. Butwith the time or an accident the natural movement of thehands are lost. Now a days due to increase in the worldpopulation with the significant aging is forcing the rapid risesin the health care department. The health care departmentis going through such an innovative transformation whereit is possible to monitor the patients without the regulardoctor visit. In such situations, wearable sensor networkstechnologies are used. Wearable sensors detect abnormalsituations by monitoring various parameters and to minimizethe need for caretakers and help the chronically ill and elderlypeople live an independent life, besides providing peoplewith quality care.

II. LITERATURE SURVEY

There have been many previous prototypes made in onesuch paper it is proposed that in the early days the integrationof wearable sensors was achieved by running wires inpockets created in garments for the purpose of monitoring.Such systems by design were not suitable for long termhealth monitoring. So Recently developed wearable system

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which integrates individual sensors into the sensor networkby relying on modern wireless communications technologyis used.[6] In the second paper which we have surveyed it ispresents the result of a pilot study to assess the feasibility ofusing accelerometer data to estimate the severity of symp-toms and monitoring patients with the Parkinson diseasesat home because every time is not possible for the doctorto monitor the patient who are suffering from Parkinsondiseases and it is due to the loss of brain cells that producedopamine. Early signs and symptoms of Parkinson’s diseaseinclude tremors or trembling, slow movement, body rigidityand stiffness, and problems walking. There are five stageof Parkinson’s disease for which there is no cure.[7] In thethird paper focuses on studying and implementing a systemfor measuring the finger position of one hand with the aimof giving feedback to the rehabilitation system. It consistsof a glove where sensors are mounted suitably configuredand connected to an electronic conditioning and acquisitionunit. The information regarding the position is then sent toa remote system. The objective of this paper is to provide asensorized glove for monitoring the rehabilitation activitiesof the hand.[7] In the last paper of survey it is proposes arehabilitation device to help patients with wrist problem to dorehabilitation treatment at home without therapist assistance.The device uses a single hand pedal mechanism that containsan accelerometer to measure acceleration exerted by theuser’s wrist motion in pitch and yaw movements. Preliminaryexperimental results show the usefulness of the proposeddevice where the movement of accelerometer sensor attachedon the device corresponds to the actual movement of thewrist. Furthermore, the uniqueness of this device is theportability and low-cost design.[8]

III. MATERIAL AND METHODS

The arduino uno board is used here to fed with the setof codes which are used to run the program. The board isknown as the brain of the project. The UNO is the mostused and documented board of the whole arduino family..Arduino board design uses variety of microprocessors andcontrollers. The boards are equipped with sets of digitaland analog input/output (I/O) pins that may be interfacedto various expansion boards and other circuits. The boardsfeature serial communications interfaces, including UniversalSerial Bus (USB) on some models, which are also used forloading programs from personal computers. And sometimessimply powered with the AC-to-DC adaptor or battery to getstarted. The Uno differs from all preceding boards in thatit does not use the FTDI USB-to-serial driver chip. Instead,it features the Atmega8U2 programmed as a USB-to-serialconverter.

MPU 6050 we are using here is a 3-axis MEMS gy-roscope, a 3-axis MEMS accelerometer. It is very usefulfor some motion detecting. This small module integrate thelogic level converter circuit(makes it compatible with 3.3V-5V voltage level) together with the MPU6050 sensor, youcan integrate it to your project conveniently.

The Flex Sensor patented technology is based on resistivecarbon elements. When the substrate is bent, the sensorproduces a resistance output correlated to the bend radiusthesmaller the radius, the higher the resistance value. High levelof reliability, consistency, repeatability and Harsh tempera-ture resistance .

IV. SYSTEM REQUIREMENTThe requirement of Wireless Sensor Glove for hand move-

ment analysis is summarised in Table 1. The requirementof Hand Movement Analysis using sensor based WirelessGlove are decided by the parameters such as Flex , linearacceleration and angler velocity. For this purpose flex sensorsis used which is interfaced with MPU 6050 and with Arduinouno and RF Transmitter Receiver is connected to glove tomake the system wireless. Arduino processes the input datagiven by flex sensors and IMU sensor and convert it intosuitable value in human readable form. When the hand isstable, the variations in the consecutive outputs flex sensorsand IMU sensors outputs are subtle i.e. very small.

The materials used are as follows1. Flex sensors2. IMU (MPU-6050 )3. RF MODULE4. Arduino board

A. Flex sensorsThe Flex Sensor principle is based on resistive carbon

elements. When the sensor is bent, it produces a resistanceoutput correlated to the bend radius that is, the smaller theradius, the higher the resistance value. Flex sensor has Highlevel of reliability, consistency, repeatability and harsh tem-perature resistance. It can be notice that one side of the sensoris printed with a polymer ink that has conductive particlesembedded in it. When the sensor is straight, resistance isabout 30k Ohms. When the sensor is bent away from theink, the conductive particles move further distant, increasingthe resistance to about 50k-70K Ohms and the sensor is bentto 90.

Fig. 1. flex sensor 1

When the sensor straightens out again, the resistancereturns to the original value. By measuring the resistance,you can determine how much the sensor is being bent.

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Electrical Specifications:Life Cycle: ¿1 millionHeight: 0.43mmTemperature Range: -35 to +80 degree celciusFlat Resistance: 25K OhmsResistance Tolerance: - 30 to 30 percentBend Resistance Range: 45K to 125K Ohms (depends on

bend radius)Power Rating : 0.50 Watts

B. Arduino Nano

The arduino nano is a small, compact and bread boardfriendly version of Atmega 328 or or ATmega168 (ArduinoNano 2.x). Over and above, it has almost the same func-tionality as of Arduino Duemilanove, but in a smaller andcompact platform. will flicker if digital pins 0 or 1 arehigh.The Arduino Nano can generally be powered via the

Mini-B USB connection, 6-20V unregulated external powersupply (pin 30), or 5V regulated external power supply (pin27).

The ATmega168 has 16 KB of flash memory for storingcode (of which 2 KB is used for the boot loader); theATmega328 has 32 KB, (also with 2 KB used for the bootloader).A nano board has 14 digital pins, each of which caneither be used as an input or output using pin Mode (), digitalWrite (), and digital Read () functions. They operate at 5volts.

Fig. 4. Arduino Nano

specification :1. Microcontroller: Atmel ATmega168 or ATmega3282. Operating Voltage(logic level): 5 V3. Input Voltage(recommended): 7-12 V4. Input Voltage(limits): 6-20 V5. Digital I/O Pins: 14 (of which 6 provide PWM output)6. Analog Input Pins: 87. DC Current per I/O Pin: 40 mA8. Flash Memory: 16 KB (ATmega168) or 32 KB (AT-

mega328) of which 2 KB used by bootloader9. SRAM: 1 KB (ATmega168) or 2 KB (ATmega328)10. EEPROM: 512 bytes (ATmega168) or 1 KB (AT-

mega328)11. Clock Speed: 16 MHz

C. PIN Configuration

The Arduino Nano has various ways of communicatingwith a computer, other Arduinos, or other microcontrollers.The ATmega168 and ATmega328 provide UART TTL (5V)


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Fig. 5. PIN Description

Fig. 6. PIN Description

serial communication, which is available on digital pins 0(RX) and 1 (TX). An FTDI FT232RL present on the boardchannels this serial communication over USB and the FTDIdrivers (included with the Arduino software) provide a virtualcom port to software on the computer. The Arduino softwareincludes a serial monitor that allows simple textual data to besent to and from the nano board. The RX and TX LEDs onthe board will start flashing when data is being transmittedvia the FTDI chip and USB connection to the computer.

D. IMU sensor

The MPU6050 we are using here is a 3-axis MEMSgyroscope, a 3-axis MEMS accelerometer. It is very usefulfor some motion detecting consecutively. It is the worldsfirst motion processing solution with integrated 9-axis sensorfusion using its field proven and proprietary Motion Fusionengine for hand set and tablet applications, Game controllersand other consumer device.Therefore it captures the x, y, andz channel at the same time. Also, it is accurate because youhave the 3 axis gyro and 3 axis accelerometers on singlechip so you do not need to align them. The sensor has a”Digital Motion Processor” (DMP), also called a ”Digital

Motion Processing Unit”. This DMP can be programmedwith firmware made by invensense and is able to do complexcalculations with the sensor values.

FEATURES:1. I2C Digital-output of 6 or 9-axis MotionFusion data in

rotation matrix, quaternion, Euler Angle, or raw data format.2. Input Voltage: 2.3 - 3.4V.3. Tri-Axis angular rate sensor (gyro) with a sensitivity up

to 131 LSBs/dps and a full-scale range of 250, 500, 1000,and 2000dps.

4. Tri-Axis accelerometer with a programmable full scalerange of 2g, 4g, 8g and 16g

5. Digital Motion Processing (DMP) engine offloadscomplex MotionFusion, sensor timing synchronization andgesture detection.

6. Digital-output temperature sensor.

Fig. 7. IMU Sensor

V. CIRCUT DIAGRAM

VI. WORKINGAn external power source is given to the nano board to

power it up. The flex sensors connected to the glove areconnected to three resistors, each of resistance value 10K.This is basically a voltage divider circuit. The purpose ofusing a voltage divider circuit is to get an output voltage thatis a relative fraction of the input voltage. The flex sensors arealso provided with Vcc via the IMU sesnsor, which is alsogiven with Vcc and ground. Now from the resistors, threewires are drawn and connected to the analog pins A1, A2and A3. The serial clock and serial data pins of the MPU6050 are connected to pins D4 and D5 of the nano board.Serial Peripheral Interface (SPI) is a synchronous serial dataprotocol used by microcontrollers for communicating withone or more peripheral devices quickly over short distances.It can also be used for communication between two mi-crocontrollers. With an SPI connection there is always one


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Fig. 8. CIRCUIT DIAGRAM

master device (usually a microcontroller) which controls theperipheral devices. Typically there are three lines commonto all the devices:

MISO (Master In Slave Out) - The Slave line for sendingdata to the master.

MOSI (Master Out Slave In) - The Master line for sendingdata to the peripherals.

SCK (Serial Clock) - The clock pulses which synchronizedata transmission generated by the master and one linespecific for every device.

SS (Slave Select) - the pin on each device that the mastercan use to enable and disable specific devices.

Once the given connections are made, the arduino isprogrammed to give the required values and measurements.Furthermore, once we see that we get the values of ac-celerometer and gyroscope in the x, y and z axis and thevalues of the flex sensors, we can go on to make the modelwireless. In order to make the model go wireless, we needto use an RF transmitter and receiver. As the name suggests,a RF module is a small electronic device that is used totransmit and receive data wirelessly by the help of radiofrequency communications. The RF transmitter convers theelectrical signal into radio waves which travel thousands ofkilometres at times. The RF receiver receives the signal fromthe transmitter and converts it into the desired signal.

Once the values are obtained, the values are taken and areal time graph is plotted to see the behaviour and deflectionof hand from the original set point values and after that thecorrective measures are taken to take care of the problem ishand movement.

VII. SIMULATION RESULTS

The one position of hand is shown in the figure and thecorresponding values of accelerometer, gyroscope and 3 flexsensors are displayed.

Fig. 9. hand position

Fig. 10. Tabular column

Thus in this way various position of hand can be observedand values of accelerometer and gyroscope can be obtained.

VIII. CONCLUSIONS

Hence the prototype for detecting the hand movement issuccessfully designed and the difference between the normalhand movement of a person and abnormal hand movementof a person is successfully distinguished.

ACKNOWLEDGMENT

The success and final outcome of this project required alot of guidance and assistance from many people and I amextremely privileged to have got this all along the completionof my project. All that I have done is only due to suchsupervision and assistance and I would not forget to thankthem.I respect and thank Dr. P.A. Sridhar, for providing me a


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Fig. 11. flex sensors graph

opportunity to do the project work and giving us all supportand guidance which made me complete the project duly.I owe my deep gratitude to our project member SarthakNayak, who took keen interest on our project work andguided us all along, till the completion of our project workby providing all the necessary information for developinga good system. I would not forget to remember AtluriVenkatkrishna, for his encouragement and more over for his

Fig. 12. Accelerometer graph

timely support and guidance till the completion of our projectwork. I am thankful to and fortunate enough to get constantencouragement, support and guidance from all Teachingstaffs of Electronics and Instrumentation Department whichhelped us in successfully completing our project work. Also,I would like to extend our sincere esteems to all staff inlaboratory for their timely support.

References are important to the reader; therefore, each


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Fig. 13. Gyroscope graph

citation must be complete and correct. If at all possible,references should be commonly available publications.

REFERENCES

[1] Bradley, radley, Walter George,2004. Neurology in Clinical Prac-tice: Principles of diagnos is and management.Taylor Francis.ISBN9789997625885.

[2] Fahn, Stanley, Jankovic, Joseph, Hallett, Mark,2011. Princi-ples and Practice of Movement Disorders. Elsevier Health Sci-ences,ISBN1437737706.

[3] Flemming, Kelly, Jones, Lyell, 2015. Mayo Clinic Neurology BoardReview: Clinical Neurology for Initial Certification and MOC. OxfordUniversity Press. ISBN9780190244934.

[4] Jim Folk, Marilyn Folk, BScN. ”Body Tremors, Shaking, Trembling,Vibrating Anxiety Symptoms”. Anxiety centre.com. Retrieved Decem-ber16,2017.

[5] Poewe, Werner; Jankovic, Joseph, 2014. Movement Disorders inNeurologic and Systemic Disease. Cambridge University Press.ISBN9781107024618.

[6] CC Yang (2010), 2010 A REVIEW OF ACCELEROMETRY-BASEDWEARABLE MOTION DETECTORS FOR PHYSICAL ACTIVITYMONITORING. REPORT NUMBER- 574

[7] Paolo Bonato, Konard lorincz, 2007 ANALYSIS OF FEATURESPACE FOR MONITORING PERSONS WITH PARKINSONS DIS-EASES WITH APPLICATION TO A WIRELESS WEARABLE SEN-SOR SYSTEM. REPORT NUMBER-10.1109/IEMBS.2007.4353793

[8] MICHELA BORGHETTI, 2013 Sensorized Glove for Measur-ing Hand Finger Flexion for Rehabilitation Purposes. REPORTNUMBER-10.1109/TI.2013.2272848

[9] Radzi Ambar, Johan mohmmad sharif, MD Asri Ngadi, 2017 DE-SIGN OF ACCELEROMETER BASED WRIST REHABILITATIONDEVICE. REPORT NUMBER- 10.1109/ICT-ISPC.2017.8075342


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design of a wearable sensor glove to measure human hand

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