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Built-in project · Raspberry Pi 4 Model B

PIR motion sensor with gpiozero on a Raspberry Pi 4

gpiozero MotionSensor on a Raspberry Pi 4: an HC-SR501 PIR on GPIO4 lights an LED on GPIO17 while something moves, and counts each movement. The whole build, a Raspberry Pi 4 and 3 more parts, runs here in your browser on the Python below; open it in the editor to change the wiring or the code and run it again.

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The parts retail for about $60. On Mokxi they're free.

PIR motion sensor with gpiozero · Raspberry Pi 4 Model Blive0.000 s 0.00x
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The circuit itself, running here on the simulator. Press what can be pressed; click anything else to open it in the editor.

The code

The Python exactly as the editor opens it. Change a line there and press Run: the board runs main.py in a Python engine in the page, with gpiozero and RPi.GPIO, and nothing to compile.

main.py · Raspberry Pi 4 Model B
# A PIR motion sensor with gpiozero on a Raspberry Pi 4.
# The HC-SR501 runs from 5V (pin 2) and ground (pin 6). Its OUT is a 3.3 V
# signal, safe for a Pi pin, on GPIO4 (pin 7). The LED is on GPIO17 (pin 11)
# through a 330 ohm resistor.
from gpiozero import MotionSensor, LED

pir = MotionSensor(4)
led = LED(17)

print("Waiting for the room to be still...")
pir.wait_for_no_motion()
print("Ready")

count = 0
while True:
    pir.wait_for_motion()
    count += 1
    led.on()
    print("Motion detected!", count)
    pir.wait_for_no_motion()
    led.off()
    print("Still again")

Parts list

5 parts, plus the jumper wires. They retail for about $60; on Mokxi they're free.

How it is wired

6 connections, pin by pin, read from the circuit itself. Each line is one set of pins joined together, by a jumper wire or a breadboard strip.

  • Raspberry Pi 4 Model B pin 5V; Motion sensor pin VCC
  • Ground: Raspberry Pi 4 Model B pin GND; Motion sensor pin GND
  • Raspberry Pi 4 Model B pin GPIO4; Motion sensor pin OUT
  • Ground: Raspberry Pi 4 Model B pin GND; LED, red pin C
  • Raspberry Pi 4 Model B pin GPIO17; Resistor, 330 Ω pin 1
  • Resistor, 330 Ω pin 2; LED, red pin A

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Open it in the editor, change the circuit or the code, and keep your version in a free account.

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