Random Nerd Tutorials
Shares

Modifying Cheap PIR Motion Sensor to Work at 3.3V

Shares

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.

Before soldering

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.

pir_motion_sensor_arduino

After soldering

Here’s how it looks, now if you supply 3.3V through that red wire your module works at 3.3V.

pir_motion_sensor_arduino_3.3V

Testing

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. If you like this post probably you might like my next ones, so please support me by subscribing my blog and my Facebook Page.

Recommended Resources

Home Automation using ESP8266 »
Build IoT projects and home automation gadgets with the ESP8266 Wi-Fi module.

Build a Home Automation System »
Learn how to build a automation system using open-source hardware and software from scratch.

Arduino Step-by-Step Projects »
Build 25 cool Arduino projects with our couse even with no prior experience!

Leave a Comment:

Add Your Reply