Understanding PWM in Robotics
- Arduino, Electronics, Tutorials
In robotics, controlling how fast a motor spins or how bright an LED shines is essential. PWM — Pulse Width Modulation — is the tool that makes this possible.
Let’s dive into what PWM is, how it works, and how you can use it in your own robotic projects.
PWM is a technique to simulate analog output using digital signals. Instead of sending a fixed voltage, you rapidly switch the signal on and off at a specific frequency.
The key concept is the duty cycle, which is the percentage of time the signal stays high during each cycle.
Think of PWM like flipping a light switch really fast:
If it’s ON half the time, it looks like half brightness.
If it’s ON most of the time, it looks brighter.
The faster the switch (higher frequency), the smoother the perceived output.
The duty cycle is calculated with:
Duty Cycle (%) = (TON / T) * 100
Where:
TON = Time the signal is HIGH
T = Total period of one PWM cycle (HIGH + LOW)
The frequency of the PWM signal is:
Frequency (Hz) = 1 / T
PWM is everywhere in robotic systems. Here are some of the most common use cases:
Control how fast your DC motors spin.
Servos use PWM where the pulse width determines the angle.
Dimming LEDs with PWM is energy-efficient and simple.
