PIR sensor 3

Motion detection: PIR sensor

Let's detect some motion!

What are we going to do?

In this activity you'll learn how the PIR sensors work. A passive infrared sensor (PIR sensor) is an electronic sensor that measures infrared (IR) light radiating from objects in its field of view. They are most often used in PIR-based motion detectors. We'll use it to turn a led on or off.

UNO board

You can use any Arduino UNO original or compatible board

USB cable

Depending on your board, you'll need a microUSB cable or a miniUSB cable


You need a computer with Arduino IDE software. If you don't have it, follow this link with instructions to download and install it.

Download Arduino IDE

PIR sensor brick

A PIR motion sensor brick with SVG connections

LED brick

A monocolor LED brick with integrated resistors and SVG connections

Let's get started

Follow these instructions carefully. You can click on some of the images to zoom in.

Always connect the components BEFORE powering the UNO board or YOU MAY DAMAGE YOUR BOARD OR COMPONENTS.


1. Connect your components

Zoom in

2. Open Arduino IDE

Once you've opened the editor, download and open the code from HERE

3. Connect your board

Connect your board with USB cable and wait a bit until you computer recognises it. Now select the correct serial port from Tools->Serial port->(choose correct port) COM1, 2, 3...

Click to zoom

3. Change code

If you follow the connections carefully, you won't need to change anything but if you want, you can always personalize it as long as you know what you're doing.

4. Upload to the board

Use the upload button to transfer the program to your board. Once done, you should read Upload completed. That means the transfer was succesful. If it's not succesful, try disconnecting your board and connecting it again and repeating the upload process.

5. Final result

After uploading, everything should be working as planned. Otherwise, double check connections and code.

Congratulations, you've done it! You're on the right path to be a maker! 🙂

Now, what else?

Now is your turn:

  • Think about how would you modify the code so the sensor acts differently depending on the motion detection.
  • Do you think you're capable of adding a buzzer from the previous activity and make it sound when motion is detected?


 Continue your journey with the next activity from below


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