SENSORS/ACTUATORS

Raspberry Pi - Potentiometer LED

In a previous tutorial, We have learned how to adjust the brightness of an LED based on the potentiometer's output value. This tutorial instructs you how to use Raspberry Pi and potentiometer to control LED. In detail:

Raspberry Pi turns the LED on if the potentiometer's analog value is above a certain threshold
Raspberry Pi turns the LED off if the potentiometer's analog value is below a certain threshold

Hardware Preparation

1	×	Raspberry Pi 4 Model B
1	×	Potentiometer
1	×	(Alternative) Potentiometer Kit
1	×	(Alternative) Potentiometer Module with Knob
1	×	ADS1115 ADC Module
1	×	LED Kit with resistor
1	×	LED (red)
1	×	220 ohm resistor
1	×	Breadboard
1	×	Jumper Wires
1	×	(Optional) Screw Terminal Block Shield for Raspberry Pi
1	×	(Optional) USB-C Power Cable with On/Off Switch for Raspberry Pi 4B
1	×	(Optional) Plastic Case and Cooling Fan for Raspberry Pi 4B
1	×	(Optional) HDMI Touch Screen Monitor for Raspberry Pi

Or you can buy the following sensor kits:

1	×	DIYables Sensor Kit (30 sensors/displays)
1	×	DIYables Sensor Kit (18 sensors/displays)

Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
Additionally, some of these links are for products from our own brand, DIYables .

Overview of LED and Potentiometer

If you are unfamiliar with LED and potentiometer (including pinout, function, programming, etc.), the following tutorials can help:

Wiring Diagram

This image is created using Fritzing. Click to enlarge image

To simplify and organize your wiring setup, we recommend using a Screw Terminal Block Shield for Raspberry Pi. This shield ensures more secure and manageable connections, as shown below:

Raspberry Pi Screw Terminal Block Shield

Raspberry Pi Code

Detailed Instructions

Make sure you have Raspbian or any other Raspberry Pi compatible operating system installed on your Pi.
Make sure your Raspberry Pi is connected to the same local network as your PC.
Make sure your Raspberry Pi is connected to the internet if you need to install some libraries.
If this is the first time you use Raspberry Pi, See how to set up the Raspberry Pi
Connect your PC to the Raspberry Pi via SSH using the built-in SSH client on Linux and macOS or PuTTY on Windows. See to how connect your PC to Raspberry Pi via SSH.
Make sure you have the RPi.GPIO library installed. If not, install it using the following command:

sudo apt-get update sudo apt-get install python3-rpi.gpio

Install the Adafruit_ADS1x15 library by running the following commands on your Raspberry Pi terminal:

sudo pip install Adafruit-ADS1x15

Create a Python script file potentiometer_led.py and add the following code:

""" This Raspberry Pi code was developed by newbiely.com This Raspberry Pi code is made available for public use without any restriction For comprehensive instructions and wiring diagrams, please visit: https://newbiely.com/tutorials/raspberry-pi/raspberry-pi-potentiometer-led """ import time import Adafruit_ADS1x15 import RPi.GPIO as GPIO # Create an ADS1115 ADC object adc = Adafruit_ADS1x15.ADS1115() # Set the gain to ±4.096V (adjust if needed) GAIN = 1 # Define the GPIO pin for the LED LED_PIN = 16 # Set up GPIO for the LED GPIO.setmode(GPIO.BCM) GPIO.setup(LED_PIN, GPIO.OUT) # Define the threshold value THRESHOLD = 1000 # Adjust this threshold value as needed # Main loop to read and display the analog value try: while True: # Read the raw analog value from channel A3 raw_value = adc.read_adc(3, gain=GAIN) # Convert the raw value to voltage voltage = raw_value / 32767.0 * 4.096 # Assumes 4.096 V range for GAIN=1 # Print the results print("Raw Value: {} \t Voltage: {:.2f} V".format(raw_value, voltage)) # Check if the analog value is above the threshold if raw_value > THRESHOLD: GPIO.output(LED_PIN, GPIO.HIGH) # Turn on the LED else: GPIO.output(LED_PIN, GPIO.LOW) # Turn off the LED # Add a delay between readings (adjust as needed) time.sleep(1) except KeyboardInterrupt: print("\nExiting the program.") # Clean up GPIO on exit GPIO.cleanup()

Save the file and run the Python script by executing the following command in the terminal:

python3 potentiometer_led.py

The script runs in an infinite loop continuously until you press Ctrl + C in the terminal.

Turn the potentiometer
Check out the alteration in the LED's condition

Code Explanation

Check out the line-by-line explanation contained in the comments of the source code!

Video Tutorial

Learn More

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