November 2008
Intermediate to advanced
192 pages
8h 32m
English

Photograph by Debra Underwood
Wheelchair Safety System
My daughter Katy uses an electric wheelchair and last year she went off to college. Her mom and I were concerned about Katy’s safety in navigating the campus — she might get her chair stuck or have some other type of trouble and not be able to get to her cellphone.
So I used a Parallax microcontroller to control a GSM cellphone as a “telematics” system for her wheelchair. Inside the gray box mounted on the back of her chair, I use the phone in speakerphone mode with an external microphone and speaker.
The way I did this was by leveraging the old modem “AT” command ...