Planning the Chair

It's one thing to have the idea, it's another to get out there and build it, and finally its another thing all together to spend some money to get the parts you need. Since there aren't any real local electronic stores around here, I will be buying my parts from http://www.solarbotics.com since they are Canadian, eh?

Prior to actually getting the parts, and maybe ordering stuff I don't need, or missing stuff I DO need, I need to plan the build carefully.



Makes perfect sense? Actually it isn't really all that complicated.

On the rear view of the chair you see the main display screen in green. This will show the active turn signals, brake lights, reverse indicator, and the Quote of the Day (not all at the same time). Next to it in grey is the speaker system which at this point will provide both an audible reverse signal along with proximity alarms (someone's standing too close).

The white rectangle is the breadboard. A handy little device that allows wires to be connected without the need for soldering. I'm not very good at soldering so this is a life saver. It is attached with a bunch of data wires to the Arduino UNO (in blue) which is the brains of the whole operation. The Arduino is an open source micro-controller that allows easy hacking of electronics. It can read input from sensors or humans, process that input, and send output to various other devices. For example, if the user taps the yellow touch sensor on the left side of the chair, the Arduino will know that the sensor was triggered, then tell the LED display to blink the left arrow for 5 seconds. If the proximity sensor (orange diamond on the bottom of the chair) notes there is a "something" within 1.5 meters, the Arduino will show a "You are walking too close" message on the LED display, and beep the speaker to alert the user that someone or something is behind them.

The user will signal left and right turns by tapping on the yellow circles on the sides of the chair. Tapping both at the same time will also "power down" or "power up" the system. A combination of a magnet attached to the spokes of the chair (red), and a pair of Hall-effect sensors (pink) will continuously calculate the speed and direction of the chair. If the chair slows down suddenly, the LED display will show the brake light, and if the chair goes in reverse, the reverse indicator will light up, and an audible alarm will sound.

The entire system will be powered by 5 AA batteries on the rear of the wheelchair (brown with gray stripes).

There you go, all you need to know. Simple really. Maybe I should have gone with something more complicated.