The HC-SR501 PIR motion sensor is one of the easiest to connect to an Arduino -or any other microcontroller for that matter- and can also be used as a stand alone motion detector.

How to Use PIR Motion Sensor(HC-SR501)with an Arduino: Hello dear friends;In this project , i have tried to explain how to use PIR Motion Sensor(HC-SR501) with an Arduino...As most of you know, it is using in the WC's, buildings and homes in order to lower electricty bills.In fact , you can make your ... Most PIR modules have a 3-pin connection at the side or bottom. The pinout may vary between modules so check the pinout carefully! Power is usually 3-5v DC input. The circuit connections are made as follows : Vcc pin of the HC-SR501 is connected to +3v of the NodeMCU. Output pin of the HC-SR501 is connected to Digital pin D7 of the NodeMCU. HC-SR501 PIR Motion Detector The HC-SR501 is an inexpensive PIR sensor that is readily available on eBay, Amazon and at your local electronics store. It is a completely self-contained unit capable of operating on its own or of being interfaced to a microcontroller or microcomputer.