TPad Phone

TPAD PHONE

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A Northwestern Neuroscience and Robotics (NxR) project to manufacture and distribute phones with variable friction capabilities to the haptics and human-computer interaction community in Fall 2017. 


PROJECT OVERVIEW 

Over the summer of 2017 I built and tested mobile phones with variable friction capabilities. These mobile devices can simulate the feel of a texture, shape, or dynamic force on your fingertip on a flat, glass screen outfitted with a piezo and controlled by an auxiliary PCB. I collaborated with a PhD student who was developing an application for the phone, while I prepared 35 phones for shipment to other labs and engineers.

The community is open-source and collaborative, allowing NxR to receive data through applications pushed out to the phones, while giving other scientists the ability to exploit the technology for their own research. 

 

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MY WORK  

A few steps in the process included documenting the assembly, brainstorming with the surface haptics group regarding a new method of reverse engineering textures using SynTouch Inc's 15 dimensions of texture, and setting up the calibration process with a laser dopper velocimeter (LDV) to find an optimal operating frequency for each phone.  

3D printer setup used to extrude UV curing glue to bind piezo to glass  in TPaD 

3D printer setup used to extrude UV curing glue to bind piezo to glass  in TPaD 

Testing the piezo - flat flex cable connection

Testing the piezo - flat flex cable connection

 
Front half assembly with PCB 

Front half assembly with PCB 

Calibrated phones ready to ship

Calibrated phones ready to ship


RESULTS

The 35-phone build was completed at the end of August, with units ready to distribute to other research groups. Throughout this project I gained contextual knowledge about surface haptics applications, signal processing theories, and variable friction devices, which was necessary to understand the dynamic system I was building and testing. 

Specific skills I used included 3D printing to set up a calibration station, laser cutting and modifying g-code for the piezo gluing process, and modifying an Android app for the device to sweep through various frequencies during testing.