Arduino - Door Sensor - LED

We are going to learn how to:

We will learn how to toggle LED each time door is closed in Arduino - Door Sensor Toggles LED tutorial.

Hardware Required

1×Arduino UNO or Genuino UNO
1×USB 2.0 cable type A/B
1×Door Sensor
1×LED
1×220 ohm resistor
1×Breadboard
4×Jumper Wires
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About LED and Door Sensor

If you do not know about LED and door sensor (pinout, how it works, how to program ...), learn about them in the following tutorials:

Wiring Diagram

Arduino Door Sensor LED Wiring Diagram

Image is developed using Fritzing. Click to enlarge image

Arduino Code

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-door-sensor-led */ const int DOOR_SENSOR_PIN = 13; // Arduino pin connected to the OUTPUT pin of door sensor const int LED_PIN = 3; // Arduino pin connected to LED's pin int doorState; void setup() { Serial.begin(9600); // initialize serial pinMode(DOOR_SENSOR_PIN, INPUT_PULLUP); // set arduino pin to input pull-up mode pinMode(LED_PIN, OUTPUT); // set arduino pin to output mode } void loop() { doorState = digitalRead(DOOR_SENSOR_PIN); // read state if (doorState == HIGH) { Serial.println("The door is open");; digitalWrite(LED_PIN, HIGH); // turn on LED } else { Serial.println("The door is closed"); digitalWrite(LED_PIN, LOW); // turn off LED } }

Quick Steps

  • Connect Arduino to PC via USB cable
  • Open Arduino IDE, select the right board and port
  • Copy the above code and open with Arduino IDE
  • Click Upload button on Arduino IDE to upload code to Arduino
  • 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 LED's state

Code Explanation

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

Video Tutorial

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