Arduino Nano ESP32 - Potentiometer LED

This tutorial instructs you how to use Arduino Nano ESP32 with the potentiometer to change the brightness of LED.

Hardware Preparation

1	×	Arduino Nano ESP32
1	×	USB Cable Type-A to Type-C (for USB-A PC)
1	×	USB Cable Type-C to Type-C (for USB-C PC)
1	×	Potentiometer
1	×	Alternatively, 10k Ohm Trimmer Potentiometer
1	×	Alternatively, Potentiometer Kit
1	×	Alternatively, Potentiometer Module with Knob
1	×	LED Kit
1	×	LED (red)
1	×	LED Module
1	×	Alternatively, Button and LED Kit
1	×	220Ω Resistor
1	×	Breadboard
1	×	Jumper Wires
1	×	Optionally, DC Power Jack
1	×	Recommended: Screw Terminal Expansion Board for Arduino Nano
1	×	Recommended: Breakout Expansion Board for Arduino Nano
1	×	Recommended: Power Splitter for Arduino Nano ESP32

Or you can buy the following kits:

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 .

Buy Note: Use the LED Module for easier wiring. It includes an integrated resistor.

Overview of LED and Potentiometer

We have specific tutorials about LED and potentiometer. Each tutorial contains detailed information and step-by-step instructions about hardware pinout, working principle, wiring connection to ESP32, Arduino Nano ESP32 code... Learn more about them at the following links:

Wiring Diagram

This image is created using Fritzing. Click to enlarge image

Here is the same wiring without a breadboard:

The wiring diagram between Arduino Nano ESP32 and Rotary Potentiometer LED (No Breadboard)

This image is created using Fritzing. Click to enlarge image

Jumper wires are good for a quick test, but not for a final build. Simply plug the Arduino Nano ESP32 into a Screw Terminal Expansion Board for Arduino Nano. See the diagram below for the screw terminal version.

The wiring diagram between Arduino Nano ESP32 and Rotary Potentiometer LED Screw Terminal

This image is created using Fritzing. Click to enlarge image

How To Program

Reads the input on analog pin (value between 0 and 4095)

int analogValue = analogRead(36); // GPIO36 (ADC0)

Scales it to brightness (value between 0 and 255)

int brightness = map(analogValue, 0, 4095, 0, 255);

Sets the brightness LED

analogWrite(LED_PIN, brightness);

Arduino Nano ESP32 Code

/* * This Arduino Nano ESP32 code was developed by newbiely.com * * This Arduino Nano ESP32 code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/arduino-nano-esp32/arduino-nano-esp32-potentiometer-led */ #define POTENTIOMETER_PIN A0 // The Arduino Nano ESP32 pin connected to Potentiometer pin #define LED_PIN D3 // The Arduino Nano ESP32 pin connected to LED's pin // the setup routine runs once when you press reset: void setup() { // initialize serial communication at 9600 bits per second: Serial.begin(9600); // set the ADC attenuation to 11 dB (up to ~3.3V input) analogSetAttenuation(ADC_11db); // declare LED pin to be an output: pinMode(LED_PIN, OUTPUT); } // the loop routine runs over and over again forever: void loop() { // reads the input on analog pin A0 (value between 0 and 4095) int analogValue = analogRead(POTENTIOMETER_PIN); // scales it to brightness (value between 0 and 255) int brightness = map(analogValue, 0, 4095, 0, 255); // sets the brightness LED that connects to pin 3 analogWrite(LED_PIN, brightness); // print out the value Serial.print("Analog value = "); Serial.print(analogValue); Serial.print(" => brightness = "); Serial.println(brightness); delay(100); }

Detailed Instructions

If this is the first time you use Arduino Nano ESP32, see how to setup environment for Arduino Nano ESP32 on Arduino IDE.
Copy the above code and paste it to Arduino IDE.
Compile and upload code to Arduino Nano ESP32 board by clicking Upload button on Arduino IDE
Open Serial Monitor on Arduino IDE

How to open serial monitor on Arduino IDE

Rotate the potentiometer
See the LED fading
See the result on Serial Monitor. It looks like the below:

Newbiely | Arduino IDE 2.3.8

──

☐

Newbiely.ino

···

8 Serial.println("Hello World!");

Output

Serial Monitor

Message (Enter to send message to 'Arduino Nano ESP32' on 'COM15')

New Line

9600 baud

Analog value = 6 => brightness = 1 Analog value = 34 => brightness = 8 Analog value = 89 => brightness = 22 Analog value = 149 => brightness = 37 Analog value = 214 => brightness = 53 Analog value = 297 => brightness = 74 Analog value = 365 => brightness = 90 Analog value = 431 => brightness = 107 Analog value = 510 => brightness = 127 Analog value = 589 => brightness = 146 Analog value = 695 => brightness = 173 Analog value = 790 => brightness = 196 Analog value = 970 => brightness = 241 Analog value = 996 => brightness = 248 Analog value = 1018 => brightness = 253 Analog value = 4095 => brightness = 255

Ln 11, Col 1

Arduino Nano ESP32 on COM15

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Language References

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