A Low-cost Joystick, Gesture & Voice Controlled Smart Wheelchair

Features

• With a simple mobile application connected to the car by bluetooth, the car/wheelchair can be controlled using:
  1. Joystick: A virtual joystick in the app.
  2. Gesture: Using phone's built-in accelerometer. Joystick control is achieved by tilting the phone.
  3. Voice command: Listens for Forward, Backward, Right, Left for direction control of the car.
     Voice command can be triggered by shaking the phone.
• Direction control as well as speed control of the car.
• Shows distance of the backward objects & sends caution signal on the app for backward collison.

Mobile Application

Mobile application was developed using MIT App Inventor which connects to the car via bluetooth.

A demo of the application:

Applocker
Connect bluetooth module
Joystick control	Gesture control	Voice control
Setting configurations

Hardware Requirements

• Microcontroller: Arduino UNO
• Motors: DC motors (9V)
• Motor driver: L298N DC motor driver
• Bluetooth module: HC-05
• Ultrasonic sensor: HC-SR04
• DC power source: 9V battery / Power bank

Connection diagram

How to run

1. Assemble hardware components according to connection diagram.
2. Upload code main/main.ino to Arduino.
3. Install wheel_chair_app.apk on Android.
   For iOS, import wheel_chair_app.aia in MIT App Inventor and read this post for further instructions.
4. Connect to bluetooth module & play.

Basic working principle

From the mobile application, commands are being sent as a 4 byte string.

The arduino programmed in the car responds to these commands by taking following actions:

--- Direction commands ---
For Joystick / Accelerometer
  1 = Forward
  2 = Right
  3 = Backward
  4 = Left
  
For Voice commands
  5 = Forward
  6 = Right
  7 = Backward
  8 = Left

Let a 4 byte string "XYYY" is received,
  X = Direction commands.
  YYY = Speed (0 - 100) / Timer for voice control in seconds.

For example,
"1023" = Direction is Forward (1) | Speed is 23.
"4100" = Direction is Left (4) | Speed is 100.
"5003" = Direction is Forward for speech (5) | Motor will run for 3 seconds.
"7010" = Direction is Backward for speech (7) | Motor will run for 10 seconds.
"0000" = Stop.

Results

First prototype Schofield.

Licensed under MIT License.