DC Motor Control Using Arduino DIY

 1️⃣ Introduction

A DC motor converts electrical energy into mechanical rotation. When voltage is applied to its terminals, the motor shaft rotates continuously.

However, a DC motor cannot be connected directly to Arduino because:

• Arduino provides very low current (around 20mA per pin)

• DC motors require higher current

• Motors generate back EMF (voltage spikes)

To solve this, we use a transistor as a switch.

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2️⃣ Components Required

• Arduino Uno

• DC Motor (6V–12V)

• NPN Transistor (TIP120 / 2N2222)

• 1kΩ Resistor

• 1N4007 Diode (Flyback diode)

• External Battery (9V–12V)

• Breadboard & Connecting wires

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3️⃣ Circuit Diagram

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4️⃣ Circuit Explanation

• The transistor works as a switch.

• When Arduino sends HIGH signal, the transistor turns ON.

• Motor receives power from the battery and starts rotating.

• The diode protects the circuit from voltage spikes (back EMF).

• All grounds must be connected together.

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5️⃣ Arduino Code (Motor Rotation Only)

int motorPin = 9;

void setup() {
  pinMode(motorPin, OUTPUT);
}

void loop() {
  digitalWrite(motorPin, HIGH);   // Motor ON
  delay(5000);                    // Runs for 5 seconds

  digitalWrite(motorPin, LOW);    // Motor OFF
  delay(3000);                    // Stops for 3 seconds
}

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6️⃣ How It Works

1. Arduino sends HIGH signal to pin 9

2. Transistor activates

3. Current flows from battery to motor

4. Motor shaft rotates

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7️⃣ Applications

• Robotics projects

• DIY fans

• Small automation systems

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8️⃣ Safety Tips

✔ Do not power motor from Arduino 5V
✔ Always use external power supply
✔ Use flyback diode
✔ Connect all grounds together

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9️⃣ Conclusion

Controlling a DC motor using an Arduino Uno is simple when using a transistor as a switching device. This method allows safe and efficient motor rotation control.