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!
I’m sure you have seen those inexpensive robot car chassis kits, the ones that come with two 6-volt motors. They are great fun and very useful and they even come with a couple of speed encoder disks (those little black circles full of holes). Problem is, no one tells you how to use them!
Let’s resolve that and build a robot car with speed sensors. Along the way we’ll learn how to use Interrupts, a valuable programming technique.
The HC-SR04 Ultrasonic Distance Sensor is a staple in robotics projects. This inexpensive device is capable of measuring the distance between itself and the nearest solid object from 2 to 400 centimeters. Exactly what you need to keep your bots from driving into walls!
In this article we’ll look at this sensor in depth, including ways to make it even more accurate by compensating for temperature and humidity. There’s lots of Arduino code to be has as well, so dig in!