Circuit Documentation

Summary

The circuit in question is designed to control a robotic system with various functionalities including motor control, distance measurement, Bluetooth communication, and display output. The core of the circuit is an Arduino Mega 2560, which interfaces with a range of sensors, actuators, and a display. The circuit includes motor drivers for controlling DC motors with encoders, an MPU6050 for motion tracking, IR sensors for line following, an HC-SR04 ultrasonic sensor for distance measurement, an HC-06 Bluetooth module for wireless communication, and a 7-segment display for user feedback. Power is supplied by 18650 Li-Ion batteries, and the circuit includes resistors for current limiting and a rocker switch for power control.

Component List

Arduino Mega 2560

• Microcontroller board based on the ATmega2560
• Provides a large number of IO pins for interfacing with various components

7-Segment Display (Common Anode)

• Displays numerical information
• Common anode configuration

18650 Li-Ion Batteries

• Provides power to the circuit
• Rechargeable battery cells

L298N DC Motor Driver

• Controls the direction and speed of DC motors
• Capable of driving two motors with H-bridge configuration

DC Motors with Encoders

• Actuators for the robotic system
• Integrated encoders provide feedback on motor position and speed

MPU6050

• Motion tracking device with a 3-axis gyroscope and a 3-axis accelerometer
• Used for balancing and orientation detection

IR Sensors

• Detects reflective surfaces for line following
• Outputs a digital signal

HC-06 Bluetooth Module

• Allows for wireless communication with the Arduino
• Configured for serial communication

HC-SR04 Ultrasonic Sensor

• Measures distance using ultrasonic waves
• Provides input for obstacle avoidance

Resistors (200 Ohms)

• Limits current to protect components
• Used in series with the 7-segment display segments

Rocker Switch

• Controls the power supply to the circuit
• Simple on/off mechanism

Wiring Details

Arduino Mega 2560

• 5V and GND pins provide power and ground to other components
• A4 (SDA) and A5 (SCL) are connected to the MPU6050 for I2C communication
• D2 to D11 are used for motor control signals and encoder inputs
• D18 (TX1) and D19 (RX1) are connected to the HC-06 Bluetooth module for serial communication
• D28, D26, D24, D22 are connected to resistors which then connect to the 7-segment display segments A, B, C, and D respectively
• D30 and D31 are connected to the HC-SR04 ultrasonic sensor's TRIG and ECHO pins
• D32 and D33 are connected to the IR sensors' output pins

7-Segment Display (Common Anode)

• COM pin connected to Arduino's GND
• Segment pins A to G connected to Arduino through 200 Ohm resistors

L298N DC Motor Driver

• IN1, IN2, IN3, IN4 connected to Arduino for motor control signals
• ENA, ENB connected to Arduino for PWM speed control
• OUT1, OUT2, OUT3, OUT4 connected to DC motors
• 12V and GND connected to the 18650 Li-Ion battery for power

DC Motors with Encoders

• Motor +ve and Motor -ve connected to motor driver outputs
• Encoder A and Encoder B connected to Arduino for feedback

MPU6050

• vcc and gnd connected to Arduino's 5V and GND
• sda and scl connected to Arduino's A4 (SDA) and A5 (SCL)

IR Sensors

• vcc and gnd connected to Arduino's 5V and GND
• out connected to Arduino's digital pins for signal output

HC-06 Bluetooth Module

• VCC and GND connected to Arduino's 5V and GND
• RXD and TXD connected to Arduino's D18 (TX1) and D19 (RX1)

HC-SR04 Ultrasonic Sensor

• VCC and GND connected to Arduino's 5V and GND
• TRIG and ECHO connected to Arduino's D30 and D31

Resistors (200 Ohms)

• Connected in series with the 7-segment display segments and Arduino digital pins

Rocker Switch

• Connected in-line with the power supply from the 18650 Li-Ion batteries to the Arduino's GND

Documented Code

#include <Wire.h>
#include <MPU6050.h>
#include <SoftwareSerial.h>
#include <Encoder.h>
#include <SevSeg.h> // Include the SevSeg library

// Pin Definitions
const int motor1Pin1 = 2; // H-Bridge IN1
const int motor1Pin2 = 3; // H-Bridge IN2
const int motor1PWM = 9;   // H-Bridge PWM1
const int motor2Pin1 = 4; // H-Bridge IN3
const int motor2Pin2 = 5; // H-Bridge IN4
const int motor2PWM = 10;  // H-Bridge PWM2
const int triggerPin = 30; // Ultrasonic Trigger
const int echoPin = 31;    // Ultrasonic Echo
const int irLeftPin = 32;  // Left IR Sensor
const int irRightPin = 33; // Right IR Sensor
const int buttonPin = 29;  // Mode button

// Encoder Pins
const int encoder1PinA = 6; // Encoder Motor A A
const int encoder1PinB = 7; // Encoder Motor A B
const int encoder2PinA = 8; // Encoder Motor B A
const int encoder2PinB = 11; // Encoder Motor B B

// HC-05 Bluetooth
SoftwareSerial Bluetooth(18, 19); // RX, TX

// SevSeg display
SevSeg sevseg; // Create an instance of the display

// Global variables
int currentMode = 0; // 0: Balance, 1: Obstacle Avoidance, 2: Line Following, 3: Bluetooth Control, 4: Dance
bool lastButtonState = LOW;
MPU6050 mpu;

// PID variables for balance
float kp = 2.0, ki = 0.5, kd = 1.0;
float error = 0, prevError = 0, integral = 0, derivative = 0;
float setpoint = 0; // Ideal upright position (0 degrees)
float pidOutput = 0;

// Encoder objects
Encoder encoder1(encoder1PinA, encoder1PinB);
Encoder encoder2(encoder2PinA, encoder2PinB);

// Motor speed variables
int motorSpeed1 = 0, motorSpeed2 = 0;

// Ultrasonic sensor function
long readUltrasonicDistance(int triggerPin, int echoPin) {
    digitalWrite(triggerPin, LOW);
    delayMicroseconds(2);
    digitalWrite(triggerPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(triggerPin, LOW);
    return pulseIn(echoPin, HIGH) * 0.034 / 2;
}

// PID controller function
float calculatePID(float setpoint, float currentAngle) {
    error = setpoint - currentAngle;
    integral += error;
    derivative = error - prevError;
    prevError = error;
    return (kp * error) + (ki * integral) + (kd * derivative);
}

// Set motor speed function
void setMotorSpeed(int motor, int speed) {
    if (motor == 1) {
        if (speed > 0) {
            digitalWrite(motor1Pin1, HIGH);
            digitalWrite(motor1Pin2, LOW);
        } else {
            digitalWrite(motor1Pin1, LOW);
            digitalWrite(motor1Pin2, HIGH);
            speed = -speed;
        }
        analogWrite(motor1PWM, speed);
    } else if (motor == 2) {
        if (speed > 0) {
            digitalWrite(motor2Pin1, HIGH);
            digitalWrite(motor2Pin2, LOW);
        } else {
            digitalWrite(motor2Pin1, LOW);
            digitalWrite(motor2Pin2, HIGH);
            speed = -speed;
        }
        analogWrite(motor2PWM, speed);
    }
}

// Mode switching logic based on Bluetooth input
void switchModes(char command) {
    if (command == 'N') { // Next mode
        currentMode++;
        if (currentMode > 4) currentMode = 0; // Wrap around
    } else if (command == 'P') { // Previous mode
        currentMode--;
        if (currentMode < 0