Circuit Documentation

Summary

This circuit is designed to control two 28BYJ-48 stepper motors using an Arduino UNO microcontroller and two ULN2003A breakout boards. The circuit also includes an HC-06 Bluetooth module for wireless communication, allowing the motors to be controlled via Bluetooth commands. The Arduino UNO is programmed to interpret the Bluetooth commands and drive the stepper motors accordingly.

Component List

Arduino UNO

• Microcontroller board based on the ATmega328P
• It has 14 digital input/output pins, 6 analog inputs, a 16 MHz quartz crystal, a USB connection, a power jack, an ICSP header, and a reset button.

28BYJ-48 Stepper Motor (x2)

• A small, 5-line, 4-phase stepper motor
• Can be driven by ULN2003A breakout board

HC-06

• A Bluetooth module that allows for wireless communication
• Operates at 3.3V and has RXD and TXD pins for serial communication

ULN2003A Breakout Board (x2)

• A board with a ULN2003A driver chip that can drive up to 7 inputs
• Used to amplify the control signals from the Arduino to drive the stepper motors

Wiring Details

Arduino UNO

• 5V and GND are used to power the ULN2003A breakout boards
• 3.3V and GND are used to power the HC-06 Bluetooth module
• Digital pins D4 to D11 are used to send control signals to the ULN2003A breakout boards
• Digital pins D0 (RX) and D1 (TX) are used for serial communication with the HC-06 Bluetooth module

28BYJ-48 Stepper Motor

• Each motor is connected to a ULN2003A breakout board via its BLUE, PINK, YELLOW, ORANGE, and RED wires

HC-06

• VCC connected to 3.3V on the Arduino UNO
• GND connected to GND on the Arduino UNO
• RXD connected to D1 (TX) on the Arduino UNO
• TXD connected to D0 (RX) on the Arduino UNO

ULN2003A Breakout Board

• +5V connected to 5V on the Arduino UNO
• 0V connected to GND on the Arduino UNO
• In 1 to In 4 connected to digital pins D4 to D11 on the Arduino UNO (two boards, each connected to its respective set of pins)
• BLUE wire, PINK wire, YELLOW wire, ORANGE wire, and RED wire connected to the corresponding wires of the 28BYJ-48 stepper motors

Documented Code

#include <AccelStepper.h>

// Define the pins for motor 1 
AccelStepper motor1(AccelStepper::HALF4WIRE, 8, 10, 9, 11);

// Define the pins for motor 2
AccelStepper motor2(AccelStepper::HALF4WIRE, 4, 6, 5, 7);

// Set initial rotation speed
const int rotationSpeed = 500; 

void setup() {
  // Set up the serial communication for Bluetooth
  Serial.begin(9600);

  motor1.setMaxSpeed(rotationSpeed);
  motor1.setAcceleration(500);
  motor1.setCurrentPosition(0);

  motor2.setMaxSpeed(rotationSpeed);
  motor2.setAcceleration(500);
  motor2.setCurrentPosition(0);
}

void loop() {
  // Check if data is available from the Bluetooth app
  if (Serial.available() > 0) {
    char command = Serial.read();

    // Write commands for the app
    switch (command) {
      case 'F':  // Start both motors rotating forward
        motor1.setSpeed(rotationSpeed);
        motor2.setSpeed(rotationSpeed);
        motor1.enableOutputs();
        motor2.enableOutputs();
        break;
      case 'B':  // Start both motors rotating backward
        motor1.setSpeed(-rotationSpeed);
        motor2.setSpeed(-rotationSpeed);
        motor1.enableOutputs();
        motor2.enableOutputs();
        break;
      case 'S':  // Stop and disconnect both motors
        motor1.setSpeed(0);       // Set speed to 0 to stop immediately
        motor2.setSpeed(0);       // Set speed to 0 to stop immediately
        motor1.disableOutputs();  // Disable outputs to disconnect motors
        motor2.disableOutputs();  // Disable outputs to disconnect motors
        break;
      default:
        // Ignore any other commands
        break;
    }
  }

  // Run motors
  motor1.runSpeed();
  motor2.runSpeed();
}

The code above is written for the Arduino UNO and is responsible for controlling two stepper motors via the ULN2003A breakout boards. It includes a Bluetooth communication setup to receive commands and control the motors accordingly. The AccelStepper library is used to facilitate the control of the stepper motors.