In this chapter we will build the actual alarm system hardware. I have chosen a modular design for the hardware. The hardware consists of three different PCBs or modules; they are as follows.
The first is the module that monitors various zones. In this case, two zones; so, we will be building two identical PCBs in order to monitor four zones. If you want to add zones, just build more zone modules and modify the software (the procedure for doing this was described in Chapter 3, Bigger and Better).The additional modules are shown by dashed lines in the preceding diagram.
The second module is the optically isolated output board. This is the board that is used to activate lights, sirens, and so on. You can control up to four devices with this board.
The third board is the one that makes this project a BeagleBone project. What this does is connect the other boards to BeagleBone. If you want to add zones or outputs, this is the part of the hardware that you would...