ESP32 - Potentiometer Triggers Servo Motor
This tutorial instructs you how to use ESP32 with the potentiometer to control servo motor. In detail:
- The ESP32 automatically rotates a servo motor to 90° if the potentiometer's analog value is above a threshold
- The ESP32 automatically rotates a servo motor to back to 0° if the potentiometer's analog value is under a threshold
We also learn how to convert the analog value to voltage and then use the voltage threshold to control the LED:
- The ESP32 automatically rotates a servo motor to 90° if the potentiometer's voltage is above a threshold.
- The ESP32 automatically rotates a servo motor back to 0° if the potentiometer's voltage is under a threshold.
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
Or you can buy the following sensor kits:
1 | × | DIYables Sensor Kit (30 sensors/displays) | |
1 | × | DIYables Sensor Kit (18 sensors/displays) |
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
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
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.
- 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
※ NOTE THAT:
This tutorial uses the analogRead() function to read values from an ADC (Analog-to-Digital Converter) connected to a potentiometer. The ESP32 ADC is good for projects that do NOT need high accuracy. However, for projects that need precise measurements, please note:
- The ESP32 ADC is not perfectly accurate and might need calibration for correct results. Each ESP32 board can be a bit different, so you need to calibrate the ADC for each individual board.
- Calibration can be difficult, especially for beginners, and might not always give the exact results you want.
For projects that need high precision, consider using an external ADC (e.g ADS1115) with the ESP32 or using an Arduino, which has a more reliable ADC. If you still want to calibrate the ESP32 ADC, refer to ESP32 ADC Calibration Driver
Video Tutorial
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