Motors

DC Motors with L298N

DC motors draw too much current for GPIO pins directly. The L298N is a dual H-bridge driver — it can drive two motors at up to 2A each. Connect: ENA to PWM pin (speed), IN1/IN2 to digital pins (direction), motor leads to OUT1/OUT2. 12V to VCC, separate 5V or onboard regulator for logic. analogWrite(ENA, 0-255) sets speed. IN1=HIGH,IN2=LOW = forward. IN1=LOW,IN2=HIGH = reverse.

Servo Motors

Servo motors have built-in feedback and a control circuit. They use PWM: 50Hz signal, 1–2ms pulse width controls position (0°–180°). The Servo.h library handles this: servo.attach(pin) then servo.write(angle) where angle is 0–180. Servos need their own 5V power supply for anything over small loads — powering from Arduino's 5V pin works for one small servo but will reset the Arduino with multiple servos.

Stepper Motors

Stepper motors move in discrete steps (typically 200 steps per revolution = 1.8° per step). They're precise without feedback sensors. Controlled with a driver (A4988, DRV8825). Connect STEP and DIR pins to Arduino. digitalWrite(STEP, HIGH); delayMicroseconds(100); digitalWrite(STEP, LOW) = one step. The AccelStepper library provides acceleration curves, which prevent missed steps at high speeds.

// Control servo + DC motor
#include <Servo.h>

// DC Motor (L298N)
const int ENA = 9;   // PWM speed
const int IN1 = 7;   // direction
const int IN2 = 8;

// Servo
Servo myServo;
const int SERVO_PIN = 6;

void motorForward(int speed) {   // speed: 0-255
  digitalWrite(IN1, HIGH);
  digitalWrite(IN2, LOW);
  analogWrite(ENA, speed);
}

void motorReverse(int speed) {
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, HIGH);
  analogWrite(ENA, speed);
}

void motorStop() {
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, LOW);
  analogWrite(ENA, 0);
}

void setup() {
  Serial.begin(9600);
  pinMode(ENA, OUTPUT);
  pinMode(IN1, OUTPUT);
  pinMode(IN2, OUTPUT);
  myServo.attach(SERVO_PIN);
  myServo.write(90); // center position
  Serial.println("Motors ready");
}

void loop() {
  // Sweep servo 0-180 while running DC motor forward
  Serial.println("Forward + servo sweep");
  motorForward(180);  // ~70% speed
  for (int angle = 0; angle <= 180; angle += 5) {
    myServo.write(angle);
    delay(30);
  }

  Serial.println("Reverse + servo return");
  motorReverse(180);
  for (int angle = 180; angle >= 0; angle -= 5) {
    myServo.write(angle);
    delay(30);
  }

  motorStop();
  delay(1000);
}