Arduino Smart Car Project - Obstacle Avoidance Robot

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Arduino Smart Car - Obstacle Avoidance Robot

PARTS LIST:
- Arduino Uno R3 x1
- L298N Motor Driver x1
- DC Gear Motors x2, Wheels x2, Caster Wheel x1
- Car Chassis x1, Battery Holder (4x AA)
- HC-SR04 Ultrasonic Sensor x1
- Jumper Wires, Breadboard
Total cost: about $15-20

WIRING:
Motor Driver L298N:
  IN1 - Arduino D5, IN2 - Arduino D6
  IN3 - Arduino D9, IN4 - Arduino D10
  ENA - Arduino D3 (PWM, left speed)
  ENB - Arduino D11 (PWM, right speed)
  Motor A - Left Motor, Motor B - Right Motor
  12V - Battery+, GND - Battery- and Arduino GND

Ultrasonic HC-SR04:
  VCC - Arduino 5V, GND - Arduino GND
  TRIG - Arduino A0, ECHO - Arduino A1

CODE - Basic Movement:

#define ENA 3
#define IN1 5
#define IN2 6
#define ENB 11
#define IN3 9
#define IN4 10

void setup() {
  pinMode(ENA, OUTPUT); pinMode(IN1, OUTPUT);
  pinMode(IN2, OUTPUT); pinMode(ENB, OUTPUT);
  pinMode(IN3, OUTPUT); pinMode(IN4, OUTPUT);
}

void forward() {
  digitalWrite(IN1, HIGH); digitalWrite(IN2, LOW);
  digitalWrite(IN3, HIGH); digitalWrite(IN4, LOW);
  analogWrite(ENA, 200); analogWrite(ENB, 200);
}

void backward() {
  digitalWrite(IN1, LOW); digitalWrite(IN2, HIGH);
  digitalWrite(IN3, LOW); digitalWrite(IN4, HIGH);
  analogWrite(ENA, 200); analogWrite(ENB, 200);
}

void left() {
  digitalWrite(IN1, LOW); digitalWrite(IN2, HIGH);
  digitalWrite(IN3, HIGH); digitalWrite(IN4, LOW);
}

void right() {
  digitalWrite(IN1, HIGH); digitalWrite(IN2, LOW);
  digitalWrite(IN3, LOW); digitalWrite(IN4, HIGH);
}

void stopCar() {
  digitalWrite(IN1, LOW); digitalWrite(IN2, LOW);
  digitalWrite(IN3, LOW); digitalWrite(IN4, LOW);
}

void loop() {
  forward(); delay(2000);
  stopCar(); delay(500);
  right(); delay(1000);
  stopCar(); delay(500);
}

CODE - Obstacle Avoidance:

#define TRIG A0
#define ECHO A1

long getDistance() {
  digitalWrite(TRIG, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG, LOW);
  long duration = pulseIn(ECHO, HIGH);
  return duration * 0.034 / 2;
}

void loop() {
  long dist = getDistance();
  if (dist < 20) {
    stopCar(); delay(300);
    backward(); delay(500);
    right(); delay(600);
  } else {
    forward();
  }
  delay(50);
}

UPGRADE IDEAS:
1. Bluetooth (HC-05) for phone control
2. Line tracking sensors (TCRT5000)
3. OLED display for status
4. WiFi (ESP8266) remote control
5. Camera module for FPV

BUILD TIPS:
- Test each motor before assembly
- Use cable ties for wiring
- Keep center of gravity low
- Calibrate speeds with PWM

Have fun building!