Building pressure sensing tiles to help the visually impaired better navigate spaces. This project was part of my research for the Accessibility Lab @ Carnegie Mellon.

Current Stage

Our approach to solving this problem is by using tactile surfaces or textured ground surfaces that one can sense through touch or by walking on them, perhaps in combination with some bluetooth/audio tool.

Image for post
Image for post
Having some fun learning old-school vacuum forming techniques! Pictured: Elena Deng (B Design) and me

user research

Currently, we have built a basic working prototype and are looking to test it with blind users through:

01 an informal Twitter survey
02 a formal co-design session on tile patterns and uses

The survey has received IRB approval and is now in the process of being sent out on Twitter.

Image for post
Image for post
Image for post
Image for post
Different paver types that would be discussed in the survey but also during in-person co-design sessions

Approach

problem space exploration

Going into this project, I had limited knowledge of visually impaired or blind users. I tried to learn about common navigation problems, tactile pavers, and current technology that exists for the visually impaired. The hope was to be able to come up with some guiding questions and takeaways.

Image for post
Image for post
key questions my team had going into this project

prototyping

Once we had a foundation, we started the 3D fabrication process of building tiles. For the initial prototype, we wanted to build a generic tile that could be used to sense any kind of pressure. The goal was to:

01 build something that could be uses in interviews with users
02 integrate with some audio or haptic sensing information

Image for post
Image for post

tile molds

Creating a mold that we could use for prototyping was the first step. We originally tried to 3D print tiles using a Makerbot, but due to the excessive time required, we switched over to a CNC for tile production. These tile molds were used to later mold the plastic and velostat for our initial prototype.

Image for post
Image for post

materials experimentation

We wanted something that could take pressure when stepped on. Thus, we used a combination of plastic and velostat — the plastic to withstand pressure and the velostat to sense pressure in partnership with an Arduino.

ABS plastic and placing the heat source under the plastic worked best for us.

Learning what type of plastic works best for our prototype!

vacuum forming

Image for post
Image for post

We ended up using an advanced vacuum forming machine, although the hope is that we can still find a low-cost alternative for kits.

arduino

The purpose of the Arduino is to be able sense pressure — the potential pressure that would come from stepping on a tile or using a cane to press down on a tile. We wanted to see what sort of data we could collect to better understand the feedback we could give to a user. We used copper tape to ensure conductivity between the two pieces. You can see videos of the two separate parts to the right!

Image for post
Image for post
tile + arduino integration

Reflection

The next step is to integrate audio and pressure sensing. Then, we hope to gather results of the Twitter survey and conduct in person interviews while continuing to build out the technology. The final product would be some sort of toolkit that we could hand-off so people can make interactive tiles within the buildings or outdoor spaces that they need them in.

My experience with the accessibility team has been extremely rewarding. I learned about so many prototyping tools and technologies in such a short period of time.

Links + Other Information

Last Meter Workshop Paper

Tools —

Sketch, Fusion 360, Procreate, Rapid Prototyping (CNC/MakerBot), Arduino, Vacuum Former, User Research Methods

Teammates —

Elena Deng, Emily Wu, Saiganesh Swaminathan, Kristin Williams, Patrick Carrington

Written by

HCI @ Carnegie Mellon — business + design

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store