Project Progress:

The T-Pad assembly is complete and its performance was tested by directly supplying PWM signals of varying duty-cycles and it performed as intended.

We are still debugging the firmware issues with the PIC and the communication issues in between the T-Pad and the Kindle Fire. We plan to continue working on the project even though the project officially is completed as the Term has ended.

FINAL IMAGE

Here is an image of our T-Pad Fire:

Project Progress Update

On May. 24th, group members got together and checked the missing component on the circuit board. Arjun had sent an e-mail to the designer for details of the missing capacitor. Designer replied that we need to use a multimeter to measure the capacitor of the whole circuit board and then decide which capacitor we should choose. After the measurement, we find out the current value of capacitor is 53nf and the wanted value is 58. So we needed a 5nf capacitor and put it in the parallel way to add the value of capacitor. However, we found out that we were unfortunately short for either 5nf or 10nf. So we decided to send the order list to Professor Yon Visell and ask for the capacitor. When the capacitor arrives, we can start our final test.

Project Progress Update:

Here are the update on the images of the different components:

The T-PaD:

The Circuit Board: (The circuit requires some final connections)

There has been a small delay in the assembly but the testing of the prototype will start next week to keep with the original schedule.

Update on the Development Schedule:

Check Point 1 - Assembly of the t-pad and the circuit by Tuesday (5/7/2013)

Check Point 2 - Assembly of the T-PaD Fire and software installation by Saturday (5/11/2013)

Check Point 3 - Testing 1 to be carried out by Tuesday (5/14/2013).

Check Point 4 - Corrections for problems found in Testing 1 and perform Testing 2 to be carried out by 

                         Thursday (5/16/2013)

Check Point 5 - Perform further corrections and begin qualitative testing of finished T-PaD Fire.

(The above dates are subject to change and we will also be working on trying to make a additional Android application that utilizes the T-PaD Fire.)

Preliminary Description of the evaluation results:

Qualitative evaluation techniques: Subjective feedback from independent users.

The finished prototype performance will be evaluated by testing the performance using independent user feedback and comparing it with intended results.

To elaborate; our aim is to induce an experience of different levels of  friction on the T-PaD surface and we would ask the user for feedback on what he/she experienced when using the surface.

Sketch for the Prototype:

(Still waiting on components so heres a reference of how things should resemble - will repost our own results once the components arrive.)

The following pictures are only an illustration to give an idea of how the completed parts would appear:

A Picture of the completed TPAD

A Picture of the Completed Circuit Board.

A Picture of the TPad Fire Assembly

Development schedule for the prototype is held until the components arrive.

Reference Papers for the Project:

"Squeeze Film Effect for the Design of an Ultrasonic Tactile Plate" - M´elisande Biet, Fr´ed´eric Giraud, Member, IEEE, and Betty Lemaire-Semail, Member, IEEE.

"T-PaD: Tactile Pattern Display through Variable Friction Reduction" - Laura Winfield, John Glassmire, J. Edward Colgate, Michael Peshkin.

"ShiverPaD: A Glass Haptic Surface That Produces Shear Force on a Bare Finger" - Erik C. Chubb, Student Member, IEEE, J. Edward Colgate, Member, IEEE and Michael A. Peshkin, Member, IEEE.

Abstract:

All most all commercially available touch displays have no texture to touch. Introducing an element of texture in such displays would greatly enhance the experience of using the device. However most tactile displays currently built rely on pin based arrays which cannot be easily integrated into normal touch screens. In this project we reconstruct a haptic display for creating texture sensation through variations in surface friction using the squeeze film effect between a plate and a finger. The plate is actuated using piezoelectric ceramics. Ultrasonic vibrations are thus produced and are capable of generating the squeeze film effect. This enables us to simulate variable friction on the surface of the display plate. The base device being used is a Kindle Fire 1st Generation, on top which a glass plate is placed which is the surface that is vibrated to produce the squeeze film effect.

Project Topic:

"Reconstructing the TPAD FIRE an open-source surface haptics device."

Project Group Members:

Arjun Rajasekar, Masters Student at Drexel University in the ECE Department.

Mengchen Zhang, Masters Student at Drexel University in the ECE Department.

Project Guide:

Dr.Yon Vissel, Assistant Professor at Drexel University in the ECE Department.

Project Description:

The aim of the project is to reconstruct the TPAD FIRE, a variable friction surface combined with a Kindle Fire. The Device has been designed by the Neuroscience and Robotics Lab at the North Western University.

Here is a link to the website of TPAD TABLET PROJECT; the main source of information for building the device, that will be followed during the course of this project.