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The objective of this project is to learn how to create a motion sensor that triggers a red light and buzzer when it senses movement.

You can use this Arduino-controlled alarm to trigger a variety of outputs, such as lights, motors, or even a “welcome home” message when you approach your front door.

When this project is successfully built, the sensor will detect motion and trigger an alarm buzzer to sound and an LED to light up.

This is project 21 from the Arduino Project Handbook, V1 by Mark Geddes.

We built it on a WorkBench Project Development Kit from Phase Dock.


Major components

  • Arduino Uno
  • 400 pin breadboard
  • “Always-on” battery (optional; this project can be powered from your computer)

Small components

  • Active buzzer
  • Passive infrared (PIR) motion detecting sensor
  • LED light (the Elegoo 37 Sensor Kit has one LED; we recommend you purchase additional LEDs)
  • 2000 – 5000 Ohm resistor
  • Jumper wires

WorkBench 1007 with two 2×3 Clicks, one Arduino Slide

  • Optional: one 2×3 or 1×3 Click depending on the size of your battery
  • Optional: 1007 Cover


Arduino Project Handbook, Volume 1, by Mark Geddes; this is Project 21

Get a WorkBench PDK from Phase Dock.

Elegoo 37 Sensor Kit, V2.0 (for the buzzer and PIR sensor)

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