O'Reilly logo

Raspberry Pi: Amazing Projects from Scratch by Richard Grimmett, Matthew Poole, Arush Kakkar, Ashwin Pajankar

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Getting into the zone

It may have occurred to you by now that even a modest-sized property could require plenty of door and window sensors; thus, if we used one input for each sensor, we'd soon run out unless we put more and more port expanders onto the system. The same is true for commercially available security systems.

So, the way this is dealt with is by creating zones, with each zone containing a group of sensors. A bedroom, for example, may be defined as one zone with a window sensor, a door sensor, and movement detector forming that zone. In this scenario, each sensor is connected to the next in a series (or daisy-chained); if one of them triggers, it will alert the monitoring system that there was a trigger in the zone. Obviously, though, ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required