This PIR motion sensor is a $2 sensor that is used to detect movement from humans or pets. You can read my previous tutorial on how to use this sensor with an Arduino.
I’m currently working on a new project and I needed to make this module operate at 3.3V. By default this module runs at 5V, but it has an on board voltage regulator that drops that voltage to 3.3V. With a quick online search I’ve found a blog post that explains how you can bypass the voltage regulator and use this module at 3.3V, which is exactly what I needed.
Where to buy one?
You can click here to compare the PIR motion sensor (HC-SR501) at different stores and find the best price.
Some of these modules come with pins soldered in that top right corner, so you don’t have to solder anything. You would simply connect a jumper wire to that pin that is highlighted in red (see Figure below). With my particular sensor I had to solder a small wire.
Here’s how it looks, now if you supply 3.3V through that red wire your module works at 3.3V.
I’ve tested this sensor with an Arduino using this code. The only difference between that previous blog post is that now I can power my module with the 3.3V pin of the Arduino!
Do you have any questions? Leave a comment down below!
Thanks for reading