Introduction: Quadriplegic Control of an RC Car

Picture of Quadriplegic Control of an RC Car

Overview:

Quadriplegics are unable to produce movement in their arms and legs. Without having an aid 24/7, they would not be able to get around. The goal for this project is to design a system that uses only movements from the neck up to control the direction of movement of a simulated power chair (RC car). To accomplish this, we will use headgear that contains an accelerometer to transmit position information of the head to control the direction of the power chair using bluetooth interface. Our design will be easily mountable, comfortable for the user, and have the ability to avoid unwanted movements.

Flow Block Diagram:

The image at the beginning of this section outlines the flow of data within our system and demonstrates how we will transduce data with an accelerometer to move a wheelchair using bluetooth.

Step 1: Materials Needed

Picture of Materials Needed

Required:

  1. Arduino Board (we used Arduino Uno) (x2)
  2. 2-axis accelerometer (we used the MMA-7361 by Sparkfun)
  3. Rechargeable 9V Battery
  4. 9V battery holder with 2.1mm plug
  5. Zumo Shield for Arduino
  6. Bluetooth Module (x2) (we used Bluetooth Mate Silver by Sparkfun)
  7. Wires

Optional (headmount):

  1. GoPro Headmount
  2. Cereal Box
  3. Duct Tape
  4. Adafruit Data Logger Shield

Step 2: Setting Up the Arduino Code

In this Instructable we will be used using two arduino scripts, one for the headmount connected to an accelerometer and one for motor control connected to the Zumo shield.

Code for Headmount Arduino:

For this code to work you will need the MMA-7361 library, which can be found here:

https://github.com/jeroendoggen/Arduino-MMA7361-li...

We used the accel.ino file below. Make sure that the MAC address in the code matches the code for your Zumo arduino bluetooth module.

Code for Zumo Arduino:

For this code to work you will need the Zumo library, which can be found here:

https://github.com/pololu/zumo-shield

We used the Zumo1.ino file below.

Step 3: Setting Up the Circuit

Picture of Setting Up the Circuit

Set up the circuits as shown in the diagrams above. The Quadaccel image was the arduino placed on the top of the head with the accelerometer (MMA7361) attached as described in our code and a master bluetooth module attached. The Quad Zumo image was the arduino attached to the Zumo shield with the single slave bluetooth attached.

Step 4: Assembly and Control

Picture of Assembly and Control

Once the scripts are uploaded onto the arduino boards (make sure digital pins 0 and 1 are unplugged when uploading!) and the circuits has been made, it is time to attach all the components together. The place your Zumo code arduino on the Zumo shield. To pair the bluetooth modules, turn the car on and wait for five seconds then plug the 9V battery into the head mounted arduino. You should know when they are paired when both the modules light up green. Finally, calibrate the position of the accelerometer so that when the person is in a neutral position, the car isn't moving. Now you can move your head similar to a joystick to control the movement of the car.

Comments

Kiteman (author)2015-04-20

That's a great idea, but the chap in the video uses a much greater range of movement than a quadriplegic would usually be capable of - is the system sensitive enough to be controlled via head movements alone?

Buzz.Humphrey (author)Kiteman2015-04-20

I tried to make a sensitivity parameter inside the code to modulate how much head movement was required. This was just a rough initial try but I'm sure that we could have made it more sensitive.

Kiteman (author)Buzz.Humphrey2015-04-20

OK, I grok that.

ohoilett (author)2015-04-20

Awesome guys. Can't wait to see the video!

Buzz.Humphrey (author)ohoilett2015-04-20

Thanks Orlando! This was so much fun!

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