In this chapter we covered the four most common sensors found in the average home or small business areas, and briefly discussed how they work. These sensors, with the exception of door contacts, come in all different shapes, sizes, and models.
For example, there are a number of different models of PIRs. Some are "pet tolerant", meaning that a dog or cat won't set them off in the middle of the night.
Tip
Cool fact
Well, maybe not exactly a fact, but I've been told that in tropical climates, small lizards crawling across a PIR have set it off. I suppose that a gecko up close to the sensor looks like Godzilla!
In the next chapter we will be learning the theory behind our first alarm system. We will also be writing some simple code to simulate a one-zone alarm system, using the built-in IDE of BeagleBone.
