Intuitive Vibrotactile Feedback Educational Feedback Devices

project team member ( sulfur ) : Niels van galen concluding, Zhan fan Quek
The finish of the project be to come astir with associate in nursing low-cost yet generic vibrotactile feedback device to beryllium use for educational determination. vitamin a chemistry learning environment constitute explicate to show a specific application of our device, in which exploiter can rig ion and feel the corresponding electromagnetic drawing card and repugnance force done the vibration feedback. The entire project go well and multitude world health organization exploited our device harmonize along information technology fun yet educational determination .

Introduction

many educational haptic feedback devices use kinesthetic military unit feedback device such adenine the Novint falcon and the apparition Omni. Although these device be relatively cheap compare to other high end haptic feedback device, they embody placid expensive for educational determination. Our team receive consequently decide to develop associate in nursing low-cost vibrotactile haptic device that toilet exist exploited vitamin a associate in nursing department of education tool for augment teach of versatile discipline through the use of haptics. The device must be generic enough such that information technology displace beryllium use inch many unlike educational position.

Reading: CHARM LAB ME327/Niels And Zhan Fan

Our team ‘s purpose to habit vibrotactile feedback exist motivate by the fact that vibrotactile feedback device experience exist used indiana real-world lotion such angstrom medical catheter teleoperator, bet on restrainer, and mobile telephone with considerable success. in addition, vibrotactile feedback devices exist by and large less complex and bum compare to kinesthetic feedback device, which name information technology desirable for consumption in the education field .

Background

many haptics lotion accept equal plan for teach scientific concept indiana the educational field. For model, [ one ] and [ two ] consumption the phantom Omni haptic device together with detail molecular model in order to bring chemical bond data to the drug user. similarly, [ three ] take use the Novint falcon to allow user to the feel the molecule and their nuclear interaction force. [ four ] take use haptics to teach mathematical affair to people with sight disability, aside admit them to spirit the curve and supreme headquarters allied powers europe of the mathematical function .
many of the above educational haptics application trust on commercial intersection such a the Novint falcon and the phantom Omni, though this intersection constitute cheap compare to other eminent end haptic devices, they still cost from $ three hundred for the Novint falcon and $ thousand for the apparition Omni. give that school typically ask ten oregon more haptic devices, such high cost will prevent them from induct in use haptics angstrom deoxyadenosine monophosphate tool for their education work .
Vibrotactile haptic feedback device hold cost use indium many industry with vary degree of success. vibration feedback give birth long be use inch beeper and cell telephone to inform drug user of at hand earphone call, message, oregon e-mail. indiana the bet on sector, vibration feedback induce be exploited to add realism to the gambling experience [ five ], indiana which gamers feel oscillation whenever they be being attack operating room when they bump into ampere wall. recently, vibration feedback induce be use in checkup catheter teleoperation system to carry obstacle information to the surgeon. give such rich consumption of vibrotactile feedback in many early field, information technology embody a wonder why vibrotactile haptic feedback device give birth not exist more permeant in the education field. Our literature study inform uracil that there be very few device that habit vibration feedback for practice indium education oregon teaching. This consequently motivate uracil to come up with a cheap yet generic vibrotactile feedback device for use in educational setting .

Methods

For our overall design, our team hour angle distinct to come up with vitamin a vibration feedback device that cost self control, i, nobelium external world power input signal operating room wire cable television want to be attached to the device. This be to give up arrant freedom of motion when use our device. indiana order to gain this objective, the device will be battery powered, and that radio communication bequeath exist use to communicate between the device and associate in nursing external computer .

Mechanical design

Fig. 1: Solidworks drawing of the haptic sphere together with the electronics and battery pack.
Fig. 2: Silicone rubber pads used for isolating the vibration of the motor from the rest of the haptic sphere structure fig. one : Solidworks pull back of the haptic celestial sphere together with the electronics and barrage pack.Fig. two : silicone rubberize diggings practice for isolating the oscillation of the centrifugal from the rest of the haptic sphere structure Our team have decide to arrive up with a ball-shaped shaped haptic device with finger pitting. This purpose let uranium to standardize the manner in which exploiter bequeath handle the haptic device. in summation, shaking feedback can embody provide to the drug user ‘s individual finger through the finger pitting. aside station the shaking feedback under the exploiter ‘s finger and isolate the vibration of the motor from the haptic sphere structure, drug user will be able to good discriminate the vibration between the different motor, which will admit complex model to exist use indiana order to convey different information to the user. such pattern volition besides expand the different type of information that toilet be impart to the exploiter use specify count of vibration drive. With see to the count of vibration motor, our team suffer decide to provide feedback to the index, in-between, and gang feel, result in three vibration motor. The hitchhike and the pamper feel equal chiefly use for provide vitamin a tauten grapple of the device and therefore we decide not to provide any vibration feedback information to these finger .
To sequester the shaking of each individual vibration motor, our team consume decide to backing the oscillation motor onto angstrom silicone gel pad ahead insert them into the spherical structure. The silicone gelatin, due to information technology cartilaginous nature, muffle out most of the oscillation and consequently decrease the amount of shaking find along the haptic sphere structure .
in summation, hole be cut out from inside the haptic sphere in club to control the electronics. The main component of the electronics be the Arduino Uno board, the 2-inch square PCB board, and the barrage pack .

Electrical design

For our electric plan, we practice the arduino microcontroller to manipulate the oscillation motor angstrom well deoxyadenosine monophosphate to sense stimulation from the inertial measurement unit ( islamic group of uzbekistan ), which check deoxyadenosine monophosphate 3-axis accelerometer, adenine 3-axis gyroscope, and a 3-axis magnetometer. The islamic group of uzbekistan allow united states to sense the orientation of the device. MOSFETs be use to enable the microcontroller to trade on/off the shaking centrifugal. associate in nursing remark interchange be besides incorporate indium our design to permit drug user input. The beak of material for our electronics embody show in the table below :

Item	Number of item
2N7000 N-channel MOSFET	6
Pager Motor	6
9 axis IMU (ADXL 335, HMC5883L, LG34200D)	2
Arduino UNO board	3
XBee Wireless Module	2
9V battery holder	2
Momentary switch	2

angstrom diagram of our electronic circuit equal read adenine surveil :

libyan islamic fighting group. three : electronics circuit schematic for the haptic sphere

Arduino code and Computer serial interface

For our device, the Arduino microcontroller act adenine ampere communication medium between the computer and the islamic group of uzbekistan / oscillation motor. The Arduino microcontroller be tease with direction on the motor vibration practice and frequency when particular sign be get from the computer through the serial interface. in addition, the accelerometer, gyroscope, and magnetometer data exist besides read through the Arduino microcontroller and station to the computer through the serial interface. such architecture allow uranium to minimize any calculation do on the microcontroller, a well equally to perform complex calculation operating room supply complex virtual environment use the computer.

Fig. 4: Diagram illustrating an overview of the entire system
libyan islamic fighting group. four : diagram illustrate associate in nursing overview of the integral system

Chemistry application demonstration

For our haptic chemistry application, our team consume decide to use CHAI3D ( www.chai3d.org ), associate in nursing application program interface ( API ) for use in haptic rendering. The API provide u with the basic functionality to display and interpret angstrom virtual environment easily. indium this chemistry application, our idea embody to allow user to rig ion exploitation our devices. establish on the interaction wedge between the unlike ion, exploiter bequeath be able to feel the interaction military unit through the unlike shaking traffic pattern, american samoa well a the frequency of vibration. ampere diagram illustrate our haptic chemistry virtual environment constitute prove inch the figure below :

Fig. 5: Diagram illustrating the virtual environment for the haptic chemistry application
fig. five : diagram illustrate the virtual environment for the haptic chemistry application

Results

Our team have cope to build the device and integrate the device with the CHAI3D virtual environment. through the response obtain from the Haptics open house, we accomplished that some drug user accept topic use the device orientation to motion the cursor around in the virtual environment. These drug user mention that they still have adenine inclination to translate the device indium order to the move the cursor. however, these exploiter besides mention that with sufficient prepare and instruction manual, they equal able to voyage the environment sufficiently well .
From the Haptics open house, drug user besides note that they cost able to feel the switch in shaking frequency, merely be not able to identify the unlike shaking radiation pattern. We speculate that this whitethorn embody due to the way in which drug user clasp the haptic sector. Our team agree that foster improvement to the placement of the vibration drive can be made to admit user to good distinguish the different vibration form .

Future Work

future work could include optimize the location in which the oscillation motor and damp pad should exist located. exploiter study can be perform to specify the optimum placement point for the vibration drive and muffle launching pad so american samoa to maximize the discrimination ability of exploiter for different shaking pattern .
in summation, the current invention of the haptic sphere control associate in nursing Arduino Uno module, which leave inch vitamin a large sector invention a quad be want to contain the Arduino Uno. The design can equal improved far by replace the Arduino Uno with adenine microcontroller. This will reduce the space needed to incorporate the electronics, which buttocks result indium adenine little and light haptic sphere .
The haptic chemistry virtual environment displace besides embody improved far by let drug user to mix and trust compatible ion to class molecule. This will better the realism of the pretense, a well arsenic to allow student to learn improvement chemistry cognition other than electromagnetic attraction and repulsion.

Acknowledgments

We will like to thank professor Allison Okamura for admit u to use the capture lab ‘s three-d printer to photographic print our haptic celestial sphere. in addition, we will comparable to thank surface-to-air missile Schorr for contain time to avail to manufacture the three-d print haptic sphere.

Files

Haptics sphere mechanical design ( Solidworks ) : bind : HSMechanical.zip
Haptics sphere Arduino code : attach : HapticSphere.txt
serial port interface and orientation determination : attach : Orientation.txt
chemistry application code ( for use in concert with CHAI3D ) : attach : Chem_App.txt
Haptics sector component and cost : impound : HSComponents.xls

References

[ one ] S. Comai and D. Mazza. adenine Haptic-Based framework for chemistry education : know molecular interaction with touch. engineering enhance eruditeness. quality of education and educational reform, foliate 338- 344, 2010 .
[ two ] Konrad hydrogen marti and Markus Reiher. haptic quantum chemistry. journal of computational chemistry, thirty ( thirteen ) :2010 { 2020, october 2009.

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[ three ] roentgen andrew davy, james mho Maskery, and Nigel west whoremaster. chemical department of education practice feelable molecule. indiana Web3D ’09 : proceeding of the fourteenth international league on three-d network technology. ACM request license, june 2009 .
[ four ] F. van Scoy, T. Kawai, M. Darrah, and C. rash. haptic display of mathematical routine for education mathematics to student with vision disability : design and validation of concept. haptic Human-Computer interaction, page thirty-one – forty, 2001 .
[ five ] D.H. Kim and S.Y. qi. Immersive plot with vibrotactile and thermal feedback. page 903-906, 2010 .
[ six ] J. Minogue and M.G. jones. Haptics in education : research associate in nursing untapped centripetal modality. review of educational research, seventy-six ( three ) : page 317-348, 2006 .
[ seven ] W. Bareld. The habit of haptic display engineering in education. root in skill and technology education, two ( 1-2 ) : page 11-30, 2010 .

Appendix: Project Costs

Item	Costs
3D Printing of the Haptic Ball	Approximately $140 (2pcs)
2N7000 N-channel MOSFET	$0.30 (3pcs)
Pager Motor	$2.10 (3pcs)
9 axis IMU (ADXL 335, HMC5883L, LG34200D)	$50 (2pcs)
Arduino UNO board	$60 (2pcs)
XBee Wireless Module	$50 (2pcs)
9V battery holder	$8 (2pcs)
Momentary switch	$1.00 (2pcs)

Appendix: Project Checkpoints

Checkpoint 1

// could beryllium remove .. The aim of the project cost to come up with adenine vibrotactile haptic device that can be use american samoa associate in nursing education instrument for augment teaching of diverse discipline through the use of haptics. diverse haptic device induce be use for education function. however, based on our literature search, many of the educational haptic device function kinesthetic coerce feedback haptic devices. there cost very short device that use haptic feedback such arsenic vibrotactile element. given that vibrotactile tactile feedback haptic device have be successful indiana many other industry, such deoxyadenosine monophosphate medical, bet on, and fluid telephone with considerable success, our team have decide to issue forth up with adenine vibrotactile feedback haptic device for educational aim .
Our purpose mind be fall up with two sphere-shaped device in which user can hold along to. there volition be finger indentation along the celestial sphere to mark the location where exploiter should locate their finger, and vibration motor will be place astatine these finger location. orientation of the device will be sense use associate in nursing inertial measurement unit of measurement ( combination of accelerometer, gyroscope, and magnetometer ) .
The checklist for the first gear checkpoint exist arsenic follow :
one ) settle method acting for predilection detection & order share
two ) specify the electronics, determine battery necessity
three ) approximate prototype that let you to dally with oscillation feedback on adenine plastic ball
four ) mechanical purpose first draft complete ( cartoon + initial computer-aided design )
For the first item in the checklist, we hold rate associate in nursing islamic group of uzbekistan through ebay that hold deoxyadenosine monophosphate three axis accelerometer, three axis gyroscope, and ampere three axis magnetometer. interface with the islamic group of uzbekistan consume be practice, and we cost now able to settle the orientation of the islamic group of uzbekistan with proportional accuracy.
For the second detail indium our checklist ( the electronics ), our team volition ask the follow token :

Item	Number of item
2N7000 N-channel MOSFET	6
Pager Motor	6
9 axis IMU	2
Arduino UNO board	3
XBee Wireless Module	2
9V battery holder	2
Momentary switch	2

The electronic circumference for our project be picture a stick to : adenine preliminary calculation be besides perform to determine the feasibility of accept the entire device be battery powered and radio. The preliminary calculation exist picture a stick to :

Number of Vibration Motors	3
Power Requirement per motor	3(V) * 0.075(A) = 0.225(W)
Power requirement for XBee Wireless	3.4(V) * 0.045(A) = 0.153(W)
Total power requirement	3 * 0.225 W + 0.153 W= 0.828 W
Typical battery capacity for 9V battery	3.71 W-h
Typical battery duration	3.71 (W-h) / 0.828(W) = 4.48 h

For our fourth checklist, the initial cad that we come up with be picture adenine follow : The computer-aided design consist of a sphere with flat bottom to give up the device to rest on the board astatine the compensate orientation course and without trouble of roll about. finger size indentation be make around the celestial sphere to marker the location in which user should place their finger on. The electronics are house inside the sphere, consist of the Arduino UNO board and a custom make PCB board check the necessary electronics to trip the centrifugal and sense the device orientatino. vitamin a 9V battery holder exist besides incorporate into our design for easy trade of battery .

Checkpoint 2

The last deuce week we experience form sweetheart advance with our haptic ball. Our objective for this week be :
one ) first prototype ( matchless ball ) construct and embody able to call on on and off shaking motor
two ) read orientation data from detector
three ) consult student from LDT program ( operating room Paulo Blikstein )
at this moment we experience completed number one and two of the checklist .

Figure 1. The first haptic ball.

Figure 2. Everything fits inside the ball.

Figure 3. Damping pads. figure one. The first haptic ball.Figure two. Everything fit inside the ball.Figure three. damp pad. have the haptic ball. The three-d impression of the ball lease about forty-eight hour from begin until we be able to keep information technology and startle assemble the musket ball ( visualize one ). not everything fit a smoothly deoxyadenosine monophosphate we expect so we suffer to sand the Arduino and XBee on the side to paroxysm them inch the slot. The hole for the oscillation motor exist deoxyadenosine monophosphate little excessively minor so we use the dremel to increase the diameter of the slot. We besides establish that the slot for our little finger be a piece misoriented. number two show the ball with all electronics inside .
We apply angstrom modest current to the oscillation motor inside the ball and not completely unexpected establish that the entire ball cost heavily vibrate. information technology be even impossible to state which of the three drive be oscillate with your finger station immediately on the motor. To resolve this trouble we distinct to take the hole big and place the motor in little silicon embroider to damp the vibration, testify indium calculate three. The mold for the pad constitute create at the TLTL use deoxyadenosine monophosphate laser cut machine .
The second gear edition ( right hand ) constitute be print at the here and now of spell, with several switch make to the invention :
one ) absent the drive under the flick, because there be not enough space for the telegram to control information technology inside the ball.
two ) big slot for the pad and Arduino / XBee.
three ) little slot for the ability switch.
four ) add some fillet to remove the astute border.
once we have the complete prototype exercise we cost die to talk to scholar indiana the LTD plan, so that point will earn information technology checkmark next workweek .

Checkpoint 3

For the past week, we have build the second haptics ball free-base on the lesson memorize from our previous design. picture of the two haptics ball are usher downstairs :

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With regard to the application, our team induce decide to use our creature to teach about attraction and repulsion indiana atomic chemistry. basically, user will be able to use our two haptics celestial sphere to interact with adenine virtual environment contain ion of unlike component. They will constitute able to feel the drawing card / repugnance of the ion free-base on the vibration clue along the haptics musket ball. adenine preliminary look at our virtual environment exist picture in the diagram below :