Pedro Martin's Bluetooth Letterboard Is an Assistive Aid for Students with Non-Verbal Autism

Maker Pedro Martin has released the design files for an open-hardware easy-to-build letterboard with Bluetooth connectivity, designed for use with Soma Mukhopadhyay's RPM teaching method for those with non-verbal autism.

"Mukhopadhyay created a method called RPM to open a window into [the minds of non-verbal autistic individuals] where the teacher or facilitator learns how to access the open learning channels (auditory, visual, tactile, and kinesthetic) of the student and adapts the sessions accordingly," Martin explains. "This allows them to communicate, slowly and painstakingly, by pointing at a letterboard to spell their thoughts as well as to expose them to information and interaction that they would otherwise never have."

Martin's contribution to the process is a build-it-yourself letterboard with a twist: it's electronic, rather than a simple sheet of printed or cut-out letters, and doubles as a Bluetooth keyboard compatible with the Android or iOS tablets to which teachers often try to progress their students as they increase in their abilities.

"[It sends] its output to an iOS or Android tablet which provides spoken feedback of each character and word through its Text-To-Speech capabilities," Martin notes of his creation, "also providing visual feedback on the letterboard thru LEDs on each letter and a piezo for clicking sounds. The hope is that, by adding visual and audio feedback to its shape and form, each letter acquires a distinct sensory fingerprint that may create stronger bonds to bridge the gap between intention and action."

The board is a 22×14 matrix of touch electrodes, each made up of its own 2×3 matrix of copper pads. These are wired to Adafruit MPR121 Capacitive Touch Sensor Breakout boards, which in turn is connected to an Adafruit ESP32 Feather development board. Finally, the board also includes a 10×6 LED matrix and a small piezo buzzer for feedback.

"It would have been orders of magnitude easier to create a simple App on iOS/Android (and there are many commercially available apps for assistive communication)," Martin admits, "but some autistic individuals perceive the light emitted by a screen as sensory noise, and others associate the screen of a tablet to game time (i.e. YouTube, games, etc.), disrupting their efforts at purposeful communication."

Martin has released the design files, a 3D-printable enclosure, and source code for the board, which was his first-ever PCB design, on the project's Hackaday.io page under an unspecified open source license.