ESP32 - Potentiometer Triggers Servo Motor

This tutorial instructs you how to use ESP32 with the potentiometer to control servo motor. In detail:

We also learn how to convert the analog value to voltage and then use the voltage threshold to control the LED:

If you want to control the angle of servo motor in proportion to the value of potentiometer, see ESP32 - Servo motor controlled by potentiometer tutorial

Hardware Used In This Tutorial

1×ESP-WROOM-32 Dev Module
1×USB Cable Type-C
1×Potentiometer
1×Servo Motor
1×Breadboard
1×Jumper Wires
1×(Optional) DC Power Jack
1×(Recommended) ESP32 Screw Terminal Adapter

Or you can buy the following sensor kit:

1×DIYables Sensor Kit 30 types, 69 units
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Introduction to Servo Motor and Potentiometer

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

Wiring Diagram

ESP32 Potentiometer Servo Motor Wiring Diagram

This image is created using Fritzing. Click to enlarge image

If you're unfamiliar with how to supply power to the ESP32 and other components, you can find guidance in the following tutorial: How to Power ESP32.

ESP32 Code - Analog Threshold

/* * This ESP32 code is created by esp32io.com * * This ESP32 code is released in the public domain * * For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-potentiometer-triggers-servo-motor */ #include <Servo.h> #define POTENTIOMETER_PIN 36 // ESP32 pin GPIO36 (ADC0) connected to Potentiometer pin #define SERVO_PIN 26 // ESP32 pin GPIO26 connected to Servo Motor's pin #define ANALOG_THRESHOLD 1000 Servo servo; // create servo object to control a servo void setup() { servo.attach(SERVO_PIN); // attaches the servo on pin 9 to the servo object servo.write(0); } void loop() { int analogValue = analogRead(POTENTIOMETER_PIN); // read the input on analog pin if (analogValue > ANALOG_THRESHOLD) servo.write(90); // rotate servo motor to 90 degree else servo.write(0); // rotate servo motor to 0 degree }

Quick Instructions

  • If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE.
  • Do the wiring as above image.
  • Connect the ESP32 board to your PC via a micro USB cable
  • Open Arduino IDE on your PC.
  • Select the right ESP32 board (e.g. ESP32 Dev Module) and COM port.
  • Click to the Libraries icon on the left bar of the Arduino IDE.
  • Type ServoESP32 on the search box, then look for the servo library by Jaroslav Paral. Please be aware that both version 1.1.1 and 1.1.0 are affected by bugs. Kindly choose a different version.
  • Click Install button to install servo motor library for ESP32.
ESP32 servo motor library
  • Copy the above code and paste it to Arduino IDE.
  • Compile and upload code to ESP32 board by clicking Upload button on Arduino IDE
  • Rotate the potentiometer
  • See servo motor rotating

ESP32 Code - Voltage Threshold

The analog value read from the potentiometer is converted to voltage, and then the voltage is compared to a voltage threshold. If it exceeds the threshold, it triggers a servo motor

/* * This ESP32 code is created by esp32io.com * * This ESP32 code is released in the public domain * * For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-potentiometer-triggers-servo-motor */ #include <Servo.h> #define POTENTIOMETER_PIN 36 // ESP32 pin GPIO36 (ADC0) connected to Potentiometer pin #define SERVO_PIN 26 // ESP32 pin GPIO26 connected to Servo Motor's pin #define VOLTAGE_THRESHOLD 2.5 // Voltages Servo servo; // create servo object to control a servo void setup() { servo.attach(SERVO_PIN); // attaches the servo on pin 9 to the servo object servo.write(0); } void loop() { int analogValue = analogRead(POTENTIOMETER_PIN); // read the input on analog pin float voltage = floatMap(analogValue, 0, 1023, 0, 5); // Rescale to potentiometer's voltage if (voltage > VOLTAGE_THRESHOLD) servo.write(90); // rotate servo motor to 90 degree else servo.write(0); // rotate servo motor to 0 degree } float floatMap(float x, float in_min, float in_max, float out_min, float out_max) { return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min; }

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