ESP32 - Ultrasonic Sensor - Relay
This tutorial instructs you how to use ESP32 and Ultrasonic sensor to control the relay. In detail:
- The ESP32 automatically turns relay on when an object is close to the ultrasonic sensor.
- The ESP32 automatically turns relay off when an object is far from the ultrasonic sensor.
We can extend this tutorial to use the ultrasonic sensor to control a led strip, siren, light bulb, or motor... by connnecting them to the relay.
Hardware Used In This Tutorial
|1||×||ESP-WROOM-32 Dev Module|
|1||×||Micro USB Cable|
|1||×||Warning Light Bright Waterproof|
|1||×||12V Power Adapter|
|1||×||(Optional) 5V Power Adapter|
|1||×||(Optional) DC Power Jack|
|1||×||(Optional) ESP32 Screw Terminal Adapter|
Introduction to Relay and Ultrasonic Sensor
We have specific tutorials about relay and ultrasonic sensor. 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:
This image is created using Fritzing. Click to enlarge image
- 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.
- Copy the above code and paste it to Arduino IDE.
- Compile and upload code to ESP32 board by clicking Upload button on Arduino IDE
- Move your hand in front of sensor
- See the change of relay's state
Line-by-line Code Explanation
The above ESP32 code contains line-by-line explanation. Please read the comments in the code!
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