🎚️ Rotary Potentiometer

📌 Description

A rotary potentiometer is a knob that you can turn to change resistance. In electronics, it’s often used to adjust values like volume, brightness, or speed. By turning the knob, the potentiometer outputs a voltage that the microcontroller can read.

🎯 Use

In our projects, the rotary potentiometer is used to:

Control LED brightness.
Adjust motor speed.
Provide manual input to the robot (like a dial).

👉 Think of the potentiometer as the robot’s volume knob — you turn it, and the robot changes something.

Module parameters

Pin name	Description
G	GND (Power Input Negative)
V	VCC (Power Input Cathode)
S	Analog signal pins

Supply voltage: 3.3V/5V
Connection: PH2.0 terminal wire
Installation method: double screw fixing

🖥️ Code Explanation

import machine

value = 0
adc4 = machine.ADC(machine.Pin(4))       # Potentiometer connected to pin 4
pwm25 = machine.PWM(machine.Pin(25))     # LED or motor connected to pin 25
pwm25.freq(1000)                         # PWM frequency set to 1000 Hz

while True:
    value = adc4.read()                  # Read potentiometer value (0–4095)
    pwm25.duty(value)                    # Set PWM duty cycle to match value

Step by Step

adc4 = machine.ADC(machine.Pin(4)) → Reads the potentiometer’s voltage (analog input).
pwm25 = machine.PWM(machine.Pin(25)) → Sets up PWM output on pin 25 (to control LED or motor).
pwm25.freq(1000) → Sets PWM frequency to 1000 Hz (smooth control).
while True: → Loop that repeats forever.
value = adc4.read() → Reads the potentiometer’s position (0–4095).
pwm25.duty(value) → Adjusts LED brightness or motor speed based on knob position.

👉 Together, this program makes the LED or motor respond directly to the potentiometer’s rotation.

✅ Conclusion of the Test

If turning the potentiometer changes the LED brightness or motor speed, the program is working correctly.
This test shows how the robot can read analog input and control output with PWM.
Later, the potentiometer could be used to adjust robot speed, sensor sensitivity, or even menu navigation on a display.