Why Motor speed control with PWM in Arduino? - Purpose & Use Cases

The Big Idea

What if you could control motor speed as smoothly as turning a dimmer switch on a lamp?

The Scenario

Imagine you want to control the speed of a motor by turning it on and off manually with a switch or button.

You try to adjust the speed by quickly flipping the switch faster or slower.

This feels like trying to control the volume of music by rapidly pressing the power button on and off.

The Problem

This manual way is very hard to do accurately.

Your hand can't flip the switch fast enough or consistently.

The motor speed jumps between full on and full off, causing jerky movement and wear.

It wastes energy and can damage the motor over time.

The Solution

PWM (Pulse Width Modulation) solves this by turning the motor on and off very fast at a steady rate.

It changes the ratio of ON time to OFF time to smoothly control speed.

This is like dimming a light by quickly flicking it on and off so fast your eyes see a steady glow.

Before vs After

✗ Before

digitalWrite(motorPin, HIGH);
delay(1000);
digitalWrite(motorPin, LOW);
delay(1000);

✓ After

analogWrite(motorPin, 128); // 50% speed using PWM

What It Enables

With PWM, you can smoothly and efficiently control motor speed with simple code and no extra hardware.

Real Life Example

Think of a remote-controlled car where you want to gently speed up or slow down instead of just full speed or stop.

PWM lets you do that easily, making the car drive smoothly and last longer.

Key Takeaways

Manual on/off control is jerky and unreliable for motor speed.

PWM uses fast switching to create smooth speed control.

This method saves energy and protects the motor.