Raspberry Pi - Door Sensor - LED
This tutorial instructs you how to use the Raspberry Pi and door sensor to control the LED. We will learn two different applications:
Application 1 - LED is on when door is open and LED is off when door is closed. The LED state is synchronized with the door sensor's state. In detail:
- Raspberry Pi turns on the LED when the door is opened.
- Raspberry Pi turns off the LED when the door is closed.
Application 2 - The LED state is toggled each time the door is opened. More specifically:
- If Raspberry Pi detects that the door has been opened (the sensor state changes from LOW to HIGH), it will turn ON the LED if it's currently OFF, or turn OFF the LED if it's currently ON.
- Closing the door sensor does not affect to the LED state.
Hardware Preparation
| 1 | × | Raspberry Pi 4 Model B | |
| 1 | × | Door Sensor | |
| 1 | × | LED | |
| 1 | × | 220 ohm resistor | |
| 1 | × | Breadboard | |
| 1 | × | Jumper Wires | |
| 1 | × | (Optional) Screw Terminal Adapter for Raspberry Pi |
Or you can buy the following sensor kits:
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
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Overview of LED and Door Sensor
If you are unfamiliar with LED and door sensor (including pinout, operation, and programming), the following tutorials can help:
Wiring Diagram
This image is created using Fritzing. Click to enlarge image
Application 1 - The LED state is in sync with the door sensor state
Detailed Instructions
- Make sure you have Raspbian or any other Raspberry Pi compatible operating system installed on your Pi.
- Make sure your Raspberry Pi is connected to the same local network as your PC.
- Make sure your Raspberry Pi is connected to the internet if you need to install some libraries.
- If this is the first time you use Raspberry Pi, See how to set up the Raspberry Pi
- Connect your PC to the Raspberry Pi via SSH using the built-in SSH client on Linux and macOS or PuTTY on Windows. See to how connect your PC to Raspberry Pi via SSH.
- Make sure you have the RPi.GPIO library installed. If not, install it using the following command:
sudo apt-get update
sudo apt-get install python3-rpi.gpio
- Create a Python script file door_sensor_led.py and add the following code:
# This Raspberry Pi code was developed by newbiely.com
# This Raspberry Pi code is made available for public use without any restriction
# For comprehensive instructions and wiring diagrams, please visit:
# https://newbiely.com/tutorials/raspberry-pi/raspberry-pi-door-sensor-led
import RPi.GPIO as GPIO
import time
# Set the GPIO mode to BCM
GPIO.setmode(GPIO.BCM)
# Define the GPIO pin numbers for the door sensor and the LED
DOOR_SENSOR_PIN = 18
LED_PIN = 20
# Setup the GPIO pin for the door sensor as an input with pull-up resistor
GPIO.setup(DOOR_SENSOR_PIN, GPIO.IN, pull_up_down=GPIO.PUD_UP)
# Setup the GPIO pin for the LED as an output
GPIO.setup(LED_PIN, GPIO.OUT)
try:
while True:
# Read the state of the door sensor (HIGH when open, LOW when closed)
door_state = GPIO.input(DOOR_SENSOR_PIN)
if door_state == GPIO.HIGH:
print("Door is OPEN")
GPIO.output(LED_PIN, GPIO.HIGH) # Turn on the LED
else:
print("Door is CLOSED")
GPIO.output(LED_PIN, GPIO.LOW) # Turn off the LED
time.sleep(0.1) # Add a small delay to avoid excessive reads
except KeyboardInterrupt:
print("Exiting...")
GPIO.cleanup()
- Save the file and run the Python script by executing the following command in the terminal:
python3 door_sensor_led.py
- Open and close the door
- Check out the change in the LED's state. You will see that the LED state is in sync with the door sensor state.
The script runs in an infinite loop continuously until you press Ctrl + C in the terminal.
Code Explanation
Check out the line-by-line explanation contained in the comments of the source code!
Application 2 - Door Sensor toggles LED
Detailed Instructions
- Create a Python script file door_sensor_toggle_led.py and add the following code:
# This Raspberry Pi code was developed by newbiely.com
# This Raspberry Pi code is made available for public use without any restriction
# For comprehensive instructions and wiring diagrams, please visit:
# https://newbiely.com/tutorials/raspberry-pi/raspberry-pi-door-sensor-led
import RPi.GPIO as GPIO
import time
# Set the GPIO mode to BCM
GPIO.setmode(GPIO.BCM)
# Define the GPIO pin numbers for the door sensor and the LED
DOOR_SENSOR_PIN = 18
LED_PIN = 20
# Setup the GPIO pin for the door sensor as an input with pull-up resistor
GPIO.setup(DOOR_SENSOR_PIN, GPIO.IN, pull_up_down=GPIO.PUD_UP)
# Setup the GPIO pin for the LED as an output
GPIO.setup(LED_PIN, GPIO.OUT)
# Variable to keep track of the previous door state
prev_door_state = GPIO.input(DOOR_SENSOR_PIN)
# Variable to keep track of the LED state
led_state = False # False for LED off, True for LED on
try:
while True:
# Read the state of the door sensor (HIGH when open, LOW when closed)
door_state = GPIO.input(DOOR_SENSOR_PIN)
if door_state != prev_door_state:
if door_state == GPIO.HIGH:
print("Door is OPEN")
led_state = not led_state # Toggle the LED state
GPIO.output(LED_PIN, led_state) # Update the LED state
# Update the previous door state
prev_door_state = door_state
time.sleep(0.1) # Add a small delay to avoid excessive reads
except KeyboardInterrupt:
print("Exiting...")
GPIO.cleanup()
- Save the file and run the Python script by executing the following command in the terminal:
python3 door_sensor_toggle_led.py
The script runs in an infinite loop continuously until you press Ctrl + C in the terminal.
- Open and close the door several times.
- Check out the change in the LED's state. You will see that the LED state is toggled once each time the door is closed.