Specialized Assistive Device Uses Haptics to Display Braille
In a departure from other braille readers, this one vibrates a pattern of dots to show information — and at a much lower cost.
Existing assistive technologies
Assistive technologies are hugely important to those who experience disabilities, as they allow people to regain functionality that would otherwise be lost. And for blindness in particular, there is text-to-speech (TTS) software that translates written text into audio, and refreshable braille displays that can dynamically arrange braille dots into something readable. However, the former is often inconvenient/slow to use while the latter can cost several thousands of dollars, so Instructables user bjmajorspin decided to build his own low-cost alternative.
The design
Instead of the traditional braille reader approach that utilizes a grid of moving dots, bmajorspin's design revolves around the inclusion of haptic feedback on just six statically-positioned dots. When the user wishes to read something onscreen, an external host can send commands which the braille reader will then interpret and display via the dots. Improved convenience is also available thanks to magnets in the housing that cause the case to stick to the back of a phone, thus letting the user read and touch the screen simultaneously.
Electronics and assembly
The microcontroller receiving the display commands is an Arduino Nano 33 BLE since it can be configured to act as a Bluetooth Low-Energy server. A set of six haptic vibration motors were connected to the Nano's digital IO pins through a series of MOSFET drivers, pull-down resistors, and flyback diodes, and when activated, produce a noticeable buzz. After some testing, the circuit was soldered to a piece of perf-board and mounted within the 3D-printed housing.
One concern that bmajorspin expressed in his write-up is focused on how to best isolate the dots since the vibrations from one motor can interfere with other nearby ones. So rather than directly connecting the dots to the motors, a spring was placed in-between that acts as a damper for any excess noise.
Programming and the app
Currently, the Android app that bmajorspin created presents the user with either a text field for entering test data or a numeric slider that demonstrates how quickly the braille reader can respond to changes in input. When a new command is ready, the app sends an encoded dot pattern to the Nano 33 BLE, which promptly decodes the value and translates it into a usable set of outputs for the motors.
Next steps
Bmajorspin has been able to test his assistive device with one blind individual so far, and the results were promising at low output speeds but became less successful when the speed was increased. In the near future, bmajorspin hopes to make several improvements to the haptic isolation, housing size, and firmware for smoother operation. More information about this braille reader can be found on its project page.