ESP32 - Door Sensor - Relay

We are going to learn how to:

We will learn how to toggle relay each time door is closed in ESP32 - Door Sensor Toggles Relay tutorial.

By connecting relay to light bulb, led strip, motor or actuator... We can use the door sensor to control light bulb, led strip, motor or actuator...

Hardware Required

1×ESP-WROOM-32 Dev Module
1×Micro USB Cable
1×Door Sensor
1×Relay
1×Warning Light Bright Waterproof
1×12V Power Adapter
n×Jumper Wires
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About Relay and Door Sensor

If you do not have knowledge of relay and door sensor (pinout, how they work, how to connect them to ESP32, how to program for them...), learn about them in the following tutorials:

Wiring Diagram

ESP32 Door Sensor Relay Wiring Diagram

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ESP32 Code

/* * Created by esp32io.com * * This example code is in the public domain * * Tutorial page: https://esp32io.com/tutorials/esp32-door-sensor-relay */ const int DOOR_SENSOR_PIN = 21; // ESP32 pin GIOP21 connected to door sensor's pin const int RELAY_PIN = 27; // ESP32 pin GIOP27 connects to the IN pin of relay int doorState; void setup() { Serial.begin(9600); // initialize serial pinMode(DOOR_SENSOR_PIN, INPUT_PULLUP); // set ESP32 pin to input pull-up mode pinMode(RELAY_PIN, OUTPUT); // set ESP32 pin to output mode } void loop() { doorState = digitalRead(DOOR_SENSOR_PIN); // read state if (doorState == HIGH) { Serial.println("The door is open"); digitalWrite(RELAY_PIN, HIGH); // turn on relay } else { Serial.println("The door is closed"); digitalWrite(RELAY_PIN, LOW); // turn off relay } }

Quick Steps

  • If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE
  • Connect the ESP32 board to your PC via a micro USB cable
  • Open Arduino IDE, select the right ESP32 board and COM port
  • Copy the above code and paste it to Arduino IDE
  • Click Upload button on Arduino IDE to compile and upload code to ESP32 board
  • Arduino IDE Upload Code
  • Move the magnet close to the reed switch and them move it far from the reed switch.
  • See the change of relay's state

Code Explanation

Read the line-by-line explanation in comment lines of source code!

Video Tutorial

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