Control an LED with a PIR Motion Sensor on Raspberry Pi

This guide demonstrates how to use Raspberry Pi hardware to read a Passive Infrared (PIR) motion sensor and control an external LED. The example is built within Simulink®, enabling you to create and run models directly on the Pi.

Introduction

The Raspberry Pi target for Simulink® provides a library of blocks that configure and access Pi peripherals. In this example, you’ll learn how to read motion events from a PIR sensor and trigger an LED in response.

Prerequisites

• Complete the “Getting Started with Raspberry Pi® Hardware” tutorial first.

Required Hardware

• Raspberry Pi board
• Parallax PIR motion sensor
• 1.8 mm red LED
• 270 Ω resistor
• Optional: Breadboard and jumper wires (recommended)
• Optional: Speakers or headphones (Task 3)
• Optional: USB webcam (Task 4)

Task 1 – Wiring the PIR Sensor and LED

The PIR sensor has three pins: VCC, GND, and OUT. Connect VCC to the 3.3 V rail, GND to ground, and OUT to a GPIO pin on the Pi. The LED circuit is connected to the same GPIO pin. Because the Pi’s GPIO operates at 3.3 V, use a 1.8 V red LED and a 270 Ω resistor to limit current.

1. Wire the PIR sensor as shown in the schematic.
2. Connect the red LED and resistor to the indicated GPIO pin.

Note: If a PIR sensor is unavailable, a momentary push‑button can substitute the OUT pin for testing.

For more detail: Motion Sensor