Using HC-SR505 PIR motion SEnsor and 2n3904 npn transistor to make motion detection night light

Arduino & Electronics Leave a comment

Circuit diagram and things you need:

The diffuser is just to break or soften the LED light, to make it more comfortable to look at. You may also need an enclosure for this project if you want to make it permanent and more nice to look at.
Wiring to perf board done. Forgotten to trim the board. Transistor is soldered to board.
2N3904 NPN transistor, hard to spot but it’s there. 😀

The HC-SR505 PIR sensor is affordable and small in size but it is very sensitive. I place it near the air-con air flow( not directly at the cool air path), the LED light goes ‘on’ and ‘off’ repeatedly without object moving in its sensing area. And its sensitivity cannot be adjusted also its ‘on’ timing (approx. 6-10 seconds) is fixed.

An enclosure was made to hold this project together and making it look more like a finished product/ project.

Following this post, I will use a more expensive PIR motion sensor and see its performance. Will update again in another post. Meanwhile keep building and making. 🤙