This is a project that we completed for a biomedical engineering instrumentation course at Vanderbilt University. The point of this project was to simulate the components necessary to design and build a method of controlling an electric wheelchair for a person unable to use their arms or legs. The method we chose was supposed to be easy to detect, comfortable to use, and reliable. Additionally, because any users of this technology will be unable to use their arms or legs, the method of control can only be interfaced with actions made from the user’s neck and up.
For our project, we decided to use infrared distance sensors to control the motion of the wheelchair. Since this project was only a simulation, we used a Polulu Zumo shield to simulate a motorized wheelchair. Because the Zumo shield was too small for a person to comfortably ride around on, we used RF transmission to pass signals from the IR distance sensors to the Zumo shield.
Step 1: Supplies
Polulu Zumo Robot Shield for Arduino
2X Arduino Uno Boards
5X Sharp IR Distance Sensors (Digi-Key part number 425-2854-ND)
434 MHz RF Transmitter (Digi-Key part number 1568-1175-ND)
434 MHz RF Receiver (Digi-Key part number 1568-1173-ND)
Soldering iron and solder
4X AA batteries
9V-to-barrel jack adapter
Step 2: Arduino Code
We used two Arduino scripts, one for the Arduino connected
to the IR sensors and one for the Arduino connected to the Zumo robot. For this software to work, you will need several Arduino libraries, as listed below:
https://github.com/pololu/zumo-shield: This library is required to interface with the Zumo shield.
http://www.airspayce.com/mikem/arduino/RadioHead/R... This library is required to send and receive data via the RF modules.
Once the libraries have been downloaded, add them to the Arduino IDE by opening the “Sketch” menu, selecting “Include Library”, clicking “Add .ZIP Library”, and then opening the downloaded .ZIP files.
Code for Sensor Arduino:
We used the Sensor_transmitter.ino file
Code for Zumo Arduino:
We used the Zumo_receiver.ino file
Step 3: Circuit Diagram
This image is similar to our set up, except replace the potentiometers with the difference in voltage between either the two side sensors or the two front/back sensors.
Step 4: Assembly
Once all of the code was uploaded and the circuits built, the collar was formed from a Styrofoam board cut into a 30x24 cm rectangle. IR distance sensors were then embedded into the collar on each side and wires run to a communal ground and +5V pin. the voltage outpu wires were then plugged into analog input channels on the sensor arduino. Once this is completed, put the collar on, turn the car on and you are ready to drive!
Step 5: Drive
Tilt your head forward to move forward, back to go back, and side to side to turn. Congratulations! You have just built your own remote control car!