2 Replies Latest reply on Dec 26, 2012 11:33 PM by mcb1

    First major Arduino Project: Wheelchair Signal Board


      I am a more "mature" student and while I have been working IT self employed style for a a few years I have returned to school to upgrade my IT skills. I have elected to take a course on building gadgets which will center around the Ardunino Uno. So far it looks interesting, and I anticipate learning a lot, but I haven't worked much with electronics. This course will involve a major project - of which I already have an idea I would like to work with - I already have the wheelchair (it's not being used anymore, fingers crossed) so that's not an expense.


      What I posted to the class forum....




      In this project, we will be solving a problem that users of manual wheelchairs face on a daily basis - they are invisible to able bodied people walking near them. This leads to collisions, and squished toes, as people don’t see the person in the wheelchair as they make turns, stop, and back up. This becomes even more important in more crowded areas like schools and shopping malls where traffic becomes stupider the more people added. The proposed solution borrows from another well known facet of Western Civilization that suffers from stupid people -- traffic.

      We will create a system that will show turn signals, break lights, reverse gear indication (along with the Beeeeep, Beeeeep, Beeeep sound) so that others will know to get out of the way of the person in the chair.  In addition to the turn signals, it can also display custom messages (easily updated in the source code), and rotate them on a regular basis. For example:

                I heard what you said about my chair
                It wasn’t very nice.

                I’m only 11 and have my own wheels.
                U Jelly?

                You can’t hurt my toes.
                My wheels can hurt yours - stay clear.

                Sit down for what you believe in!

      The system should be able to get input from the user or the environment so that the turn signals and brake signals do not have to be complicated to signal. Preferably, it should be able to read the body language of the owner, KNOW that the owner is turning left, and put on the Left Signal automagically without requiring specific input from the user. (Unlike turn signals in a car that are manually activated).

      Signals will turn off automatically after a few seconds. The user should also be able to easily turn off the system so that you don’t have distractions when settling into a classroom or other things where small, tight, maneuvers are required.


      WheelchairGirl Left Turn.png

      (Base sketch done by my daughter, I added the arrow).




      After thinking it over a bit, my thoughts on the control system are:


      1. Left and Right turn signals -> Chair user would wear special gloves and clenching their fist twice would active the turn signal, it would blink 5 times, then turn off

      2. Brake Light -> Would activate when a sensor detects the wheels are slowing down faster than a certain threshold (would have to play with the code to get something that works)

      3. Reverse light -> Is there something that can detect if the wheel is moving clockwise or counterclockwise?

      4. Custom messages - Could easily be setup in the code itself, but I'm thinking something like an iPod Touch/iPhone/iPad app that can be used. (Don't say Android, I have plenty of iDevices at home that I can play with, I don't have any Android phones). As a stretch goal, perhaps it can even display tweets, so for now I will limit the message size to 140 characters, and will have it scroll from right to left.


      The target market (although it wouldn't be used for long periods of time) would be someone with paraplegia, so leg/foot controls are out, and hand controls should be quick and simple. I'm thinking the custom messages would be something that are setup ahead of time, say while watching cat videos.


      I would like to keep the costs of parts down, but I do have a bit of a budget to work with.


      It must be controlled by an Arudino (we are using an Uno in the lab, but that exact model isn't required for the project). I have the Oomlout Arduino Experimenter's Kit, but we are also required to use parts from outside the kit.


      Suggestions for the needed sensors? A good display panel to use? Thoughts on the idea itself? Never written an iPhone app before, will it be difficult? Looks like this will be a solo project, but if I get a class partner we should be able to trick it out some more.

        • Re: First major Arduino Project: Wheelchair Signal Board

          Use bicycle led turn indicators driven by optpisolators or relays for duino protection.  Use four microswitches (mini, touch, etc.) to be activated when the user begins the movement of the joystick axis.  light pressure activates switch prior to actual movement.   mounted on joystick with cover/knob


          'If left-switch = 1; then blink left-LED"

          "If right-switch = 1 then blink right-LED"

          "If back-switch = 1 then blink reverse-LED and sound alarm"

          "If forward-switch = 0 and old-forward = 1; then brake-led lights


          leds should light for timed (5 sec) periods.

            • Re: First major Arduino Project: Wheelchair Signal Board

              The movement indications are easily possible.

              From your daughters drawing, it is intended for manual chairs rather than powered chairs.


              You could use a gyro/accelerometer to detect change of direction and drive the rear display.

              You can also detect the wheel movement using encoders, which gives you forward, reverse, left, right.



              The comments could be more difficult as you will need to enter them as you say..

              I would suggest a few smilys as a way to display messages. (smile , frown/sad , shocked )

              You can then just have a few buttons and press the appropriate one at the time.


              These can then be pre-laid out leds on a circuit board, which keeps the cost way down.