Project Documentation

Arduino Mega 2560 Controlled Robotic Vehicle with TCS230 Color Sensing and Ultrasonic Obstacle Avoidance

Circuit Documentation

Summary

This circuit is designed to control a vehicle with motorized wheels, using an Arduino Mega 2560 as the central processing unit. It features a TCS230 color sensor for detecting color changes, an HC-SR04 ultrasonic sensor for distance measurement, a Tower Pro SG90 servo for steering, and an L298N DC motor driver for controlling the motors. The circuit is powered by a 7.4V li-ion battery, and it includes a TP4056 charging module for battery management. A photocell (LDR) is used for light detection, and a buzzer is included for audio feedback. The circuit is switched on and off using a rocker switch.

Component List

L298N DC Motor Driver: A module used to control the direction and speed of DC motors.
Motor and Wheels: Four instances of this component represent the vehicle's motors and wheels.
TCS230 Color Sensor: A sensor that detects color and provides frequency output corresponding to the color detected.
Rocker Switch: A switch to control the power supply to the circuit.
Photocell (LDR): A light-dependent resistor used for detecting light levels.
HC-SR04 Ultrasonic Sensor: Two instances of this sensor are used for measuring distances by emitting ultrasonic waves.
Tower Pro SG90 Servo: A small servo motor used for precise control of angular motion.
Li-ion Battery 7.4V 3000mAh: The power source for the circuit.
TP4056 Charging Module: A module used for charging the li-ion battery.
Resistor: Two resistors with different resistance values for current limiting and voltage division.
BC547 Transistor: A general-purpose NPN transistor used for switching or amplification.
Buzzer: An audio signaling device.
Arduino Mega 2560: The microcontroller board that controls the entire circuit.

Wiring Details

L298N DC Motor Driver

ENA, ENB: Connected to Arduino Mega 2560 (PWM pins D2, D3) for speed control.
IN1, IN2, IN3, IN4: Connected to Arduino Mega 2560 (pins D22, D24, D26, D28) for direction control.
OUT1, OUT2: Connected to two motors and wheels.
OUT3, OUT4: Connected to the other two motors and wheels.
GND: Connected to the common ground.
12V: Connected to the positive terminal of the li-ion battery.
5V: Connected to the Rocker Switch.

Motor and Wheels

Four instances, each connected to the L298N DC Motor Driver's OUT1, OUT2, OUT3, and OUT4 for motor control.

TCS230 Color Sensor

VCC: Connected to the 5V output from the Arduino Mega 2560.
GND: Connected to the common ground.
Out: Connected to Arduino Mega 2560 (pin D4 PWM).
S0, S1, S2, S3: Connected to Arduino Mega 2560 (pins D36, D32, D30, D34) for frequency scaling and color selection.

Rocker Switch

Pin 1: Connected to the L298N DC Motor Driver (5V).
Pin 2: Connected to the Photocell (LDR).

Photocell (LDR)

Pin 0: Connected to Arduino Mega 2560 (pin D38).
Pin 1: Connected to the Rocker Switch.

HC-SR04 Ultrasonic Sensor

Two instances:
- VCC: Connected to the 5V output from the Arduino Mega 2560.
- GND: Connected to the common ground.
- TRIG: Connected to Arduino Mega 2560 (pins D44, D40).
- ECHO: Connected to Arduino Mega 2560 (pins D46, D42).

Tower Pro SG90 Servo

Signal: Connected to Arduino Mega 2560 (pin D48).
+5V: Connected to the 5V output from the Arduino Mega 2560.
GND: Connected to the common ground.

Li-ion Battery 7.4V 3000mAh

Positive: Connected to the TP4056 Charging Module and the L298N DC Motor Driver (12V).
Negative: Connected to the common ground.

TP4056 Charging Module

Connected to the li-ion battery for charging purposes.
Connected to the BC547 Transistor and the Buzzer for control.

Resistor

Two instances with different resistance values:
- 200 Ohms: Connected between the TCS230 Color Sensor (GND) and the common ground.
- 1500 Ohms: Connected between the TP4056 Charging Module and the BC547 Transistor (Base).

BC547 Transistor

Collector: Connected to the Buzzer (POSITIVE).
Base: Connected to the 1500 Ohms resistor.
Emitter: Connected to the common ground.

Buzzer

POSITIVE: Connected to the BC547 Transistor (Collector).
NEGATIVE: Connected to the TP4056 Charging Module.

Documented Code

#include <Servo.h>

Servo servo1;

// TCS Colour sensor pins
const int S0 = 36;
const int S1 = 32;
const int S2 = 30;
const int S3 = 34;
const int OUT = 4;

// Color frequency variables
int red_frequency;
int green_frequency;
int blue_frequency;

// L298N MOTOR DRIVER pins
const int IN1 = 22;
const int IN2 = 24;
const int IN3 = 26;
const int IN4 = 28;
const int ENA = 2;
const int ENB = 3;

// Ultrasonic sensor pins
const int trig_up = 40;
const int echo_up = 42;

// Ultrasonic sensor variables
long duration_up;
int distance_up;
int tolerance = 3;

// Servo pin
const int pin = 48;

void setup() {
  // Initialize TCS230 Color sensor
  pinMode(S0, OUTPUT);
  pinMode(S1, OUTPUT);
  pinMode(S2, OUTPUT);
  pinMode(S3, OUTPUT);
  pinMode(OUT, INPUT);

  // Initialize L298N MOTOR DRIVER
  pinMode(IN1, OUTPUT);
  pinMode(IN2, OUTPUT);
  pinMode(IN3, OUTPUT);
  pinMode(IN4, OUTPUT);
  pinMode(ENA, OUTPUT);
  pinMode(ENB, OUTPUT);

  // Initialize Ultrasonic sensor
  pinMode(trig_up, OUTPUT);
  pinMode(echo_up, INPUT);

  // Initialize Servo
  pinMode(pin, INPUT);
  servo1.attach(pin);

  // Start serial communication
  Serial.begin(9600);

  // Set frequency scaling to 20%
  digitalWrite(S0, HIGH);
  digitalWrite(S1, LOW);

  // Read initial color frequencies
  digitalWrite(S2, LOW);
  digitalWrite(S3, LOW);
  red_frequency = pulseIn(OUT, LOW);
  digitalWrite(S2, HIGH);
  digitalWrite(S3, HIGH);
  green_frequency = pulseIn(OUT, LOW);
  digitalWrite(S2, LOW);
  digitalWrite(S3, HIGH);
  blue_frequency = pulseIn(OUT, LOW);
}

void loop() {
  // Read color frequencies
  digitalWrite(S2, LOW);
  digitalWrite(S3, LOW);
  red_frequency = pulseIn(OUT, LOW);
  digitalWrite(S2, HIGH);
  digitalWrite(S3, HIGH);
  green_frequency = pulseIn(OUT, LOW);
  digitalWrite(S2, LOW);
  digitalWrite(S3, HIGH);
  blue_frequency = pulseIn(OUT, LOW);

  // Color detection logic
  if (red_frequency == 255 && green_frequency == 255 && blue_frequency == 255) {
    slow();
  } else {
    // Movement logic based on color detection
    if (red_frequency == red && green_frequency == green && blue_frequency == blue) {
      go();
    } else {
      right();
      delay(750);
      updateColorFrequencies();
      if (red_frequency != red || green_frequency != green || blue_frequency != blue) {
        left();
        delay(1500);
        updateColorFrequencies();
        if (red_frequency != red || green_frequency != green || blue_frequency != blue) {
          stop();
        } else {
          go();
        }
      } else {
        go();
      }
    }
  }

  // Ultrasonic sensor logic
  measureDistance();
  if (distance_up <= 6 + tolerance) {
    stop();
    delay(5000);
    servo1.write(45);
    measureDistance();
    if (distance_up >= 6 + tolerance) {
      right();
      delay(500);
      left();
      delay(500);
      go();
    }
  }
}

// Function definitions for motor control
void go() {
  digitalWrite(IN1, HIGH);
  digitalWrite(IN2, LOW);
  digitalWrite(IN3, HIGH);
  digitalWrite(IN4, LOW);
  analogWrite(ENA, 200);
  analogWrite(ENB, 200);
}

void back() {
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, HIGH);
  digitalWrite(IN3, LOW);
  digitalWrite(IN4, HIGH);
  analogWrite(ENA,