Created September 4, 2024

Head Motion Controlled Wheelchair for Independent Mobility

A hands-free wheelchair that empowers quadriplegics to navigate independently using head movements for control.

Things used in this project

Hardware components

Nordic Semiconductor nRF52 Development Kit

SparkFun Dual H-Bridge motor drivers L298

Adafruit Analog Accelerometer: ADXL335

Hand tools and fabrication machines

Multitool, Screwdriver

Extraction Tool, Han-Modular Modules in Plastic Frames

Story

Summary of the Project

The head motion controlled wheelchair is an innovative solution designed to enhance the mobility of individuals with quadriplegia, a condition characterized by paralysis affecting all four limbs. Traditional wheelchairs, whether manual or motorized, often require the use of hands for navigation, which poses significant challenges for those unable to use their arms. This project addresses these challenges by enabling users to control a wheelchair through simple head movements, thereby fostering independence and improving quality of life.

Design and Mechanism

The wheelchair operates using a sophisticated system comprising six high-torque motors that facilitate movement across various terrains, including ramps and slopes. The design emphasizes low-speed operation to prevent falls, making it safer for users. A helmet equipped with an accelerometer captures head tilt movements, which are then processed by an Atmega microcontroller. This microcontroller interprets the user's head movements and wirelessly transmits commands to a receiver unit integrated into the wheelchair.The receiver unit, also utilizing an Atmega microcontroller, processes these commands and directs the motor drivers to execute the necessary movements—forward, backward, left, or right—based on the user's head orientation. This intuitive control mechanism eliminates the need for hand-operated devices, making it accessible for individuals with varying degrees of mobility impairments.

Key Components

The system includes several critical components:

Atmega Microcontrollers: Serve as the brain of both the transmitter (helmet) and receiver (wheelchair).
High Torque Motors: Six geared motors provide the necessary power for movement.
RF Transmitter & Receiver: Facilitate wireless communication between the helmet and the wheelchair.
Accelerometer: Detects head tilt and translates it into movement commands.
Motor Drivers: Control the motors based on the processed commands.
Wheelchair Frame and Seat: Constructed to support the entire system and ensure user comfort.

Applications and Benefits

The primary application of this technology is to assist individuals with quadriplegia in achieving independent mobility. The wheelchair's hands-free operation makes it suitable for users with various disabilities, enhancing their ability to navigate their environment without assistance. The high-torque motors enable the wheelchair to operate effectively on inclines, and the design intentionally slows down the movement to minimize the risk of accidents.

Advantages and Disadvantages

Advantages:

Hands-Free Operation: Users can control the wheelchair solely through head movements.
Accessibility: Designed for individuals with all types of disabilities.
High Torque Performance: Allows for effective operation on slopes and uneven surfaces.
Safety Features: Slowed down operation reduces the risk of falls.

Disadvantages:

Lack of Emergency Systems: Currently, the wheelchair does not include a fall detection or emergency alert system.
Continuous Head Movement Required: Users must maintain head motion to keep the wheelchair moving, which may be tiring over extended periods.

Conclusion

The head motion controlled wheelchair represents a significant advancement in assistive technology for individuals with severe mobility impairments. By leveraging simple head movements for navigation, this project not only enhances the independence of users but also contributes to their overall quality of life. As technology continues to evolve, further refinements and additional features, such as emergency systems, could enhance the functionality and safety of this innovative mobility solution.

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Head Motion Controlled Wheelchair for Independent Mobility

#include <Wire.h>
#include <Servo.h>

Servo motor1; // Define motor 1
Servo motor2; // Define motor 2
Servo motor3; // Define motor 3
Servo motor4; // Define motor 4
Servo motor5; // Define motor 5
Servo motor6; // Define motor 6

void setup() {
  motor1.attach(9); // Attach motor 1 to pin 9
  motor2.attach(10); // Attach motor 2 to pin 10
  motor3.attach(11); // Attach motor 3 to pin 11
  motor4.attach(12); // Attach motor 4 to pin 12
  motor5.attach(13); // Attach motor 5 to pin 13
  motor6.attach(14); // Attach motor 6 to pin 14
}

void loop() {
  int headTilt = analogRead(A0); // Read head tilt angle from sensor

  // Map the head tilt value to motor commands
  if (headTilt < 300) {
    moveForward();
  } else if (headTilt > 700) {
    moveBackward();
  } else {
    stopMotors();
  }
}

void moveForward() {
  motor1.write(180); // Move forward
  motor2.write(180);
  motor3.write(180);
  motor4.write(180);
  motor5.write(180);
  motor6.write(180);
}

void moveBackward() {
  motor1.write(0); // Move backward
  motor2.write(0);
  motor3.write(0);
  motor4.write(0);
  motor5.write(0);
  motor6.write(0);
}

void stopMotors() {
  motor1.write(90); // Stop motors
  motor2.write(90);
  motor3.write(90);
  motor4.write(90);
  motor5.write(90);
  motor6.write(90);
}

Credits

Ujval R

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