Raspberry Pi - Motion Sensor - LED
This tutorial instructs you how to use Raspberry Pi and motion sensor to control LED. In detail:
- Raspberry Pi turns on the LED when movement is detected
- Raspberry Pi turns off the LED when no motion is observed
This can be applied in an automation process that triggers actions upon detecting human presence.
Hardware Preparation
| 1 | × | Raspberry Pi 4 Model B | |
| 1 | × | HC-SR501 Motion 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 Motion Sensor
If you are not familiar with LED and motion sensor (including pinout, how it works, how to program, etc.), the following tutorials will help you:
Wiring Diagram
This image is created using Fritzing. Click to enlarge image
Initial Setting
| Time Delay Adjuster | Screw it in anti-clockwise direction fully. |
| Detection Range Adjuster | Screw it in clockwise direction fully. |
| Repeat Trigger Selector | Put jumper as shown on the image. |
Raspberry Pi Code
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 motion_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-motion-sensor-led
import RPi.GPIO as GPIO
import time
# Set the GPIO mode to BCM (Broadcom SOC channel numbering)
GPIO.setmode(GPIO.BCM)
# Define the GPIO pins for the HC-SR501 PIR motion sensor and LED
PIR_PIN = 17
LED_PIN = 18
# Set up the PIR sensor and LED pins
GPIO.setup(PIR_PIN, GPIO.IN) # PIR sensor as input
GPIO.setup(LED_PIN, GPIO.OUT) # LED as output
try:
while True:
# Check if the PIR sensor detects movement (1 represents HIGH signal)
if GPIO.input(PIR_PIN) == GPIO.HIGH:
print("Motion detected!")
GPIO.output(LED_PIN, GPIO.HIGH) # Turn on the LED
else:
GPIO.output(LED_PIN, GPIO.LOW) # Turn off the LED if no motion
time.sleep(0.1) # Add a small delay to avoid excessive looping
except KeyboardInterrupt:
GPIO.cleanup() # Clean up GPIO on program exit
- Save the file and run the Python script by executing the following command in the terminal:
python3 motion_sensor_led.py
- Move your hand in front of the HC-SR501 motion sensor and check out LED's 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!