Those inexpensive RF transmitter and receiver modules that you can get on eBay and Amazon are perfect when you need a low-cost method of sending one-way data between two Arduinos.
In this article you’ll learn how these modules work and how to use them in your next Arduino project.
The HC-SR501 is a Passive Infrared (PIR) motion sensor that is extremely useful. It can be used all by itself or combined with an Arduino or Raspberry Pi
In this article you’ll learn how a PIR sensor works and you’ll build some cool projects using the HC-SR501. You can even make a motion activated camera that will tell you who is stealing your Jelly Beans!