In the second part of this chapter, we are going to learn how to build an alarm module for our security system. You will usually have one of those modules in your home that will flash light and emit sound in case motion is detected. Of course, you can perfectly connect it to a real siren instead of a buzzer to have a loud sound in case any motion is detected.
To assemble this module, first place the LED in series with the 330 Ohm resistor on the breadboard, with the longest pin of the LED in contact with the resistor. Also place the buzzer on the breadboard.
Then, connect the other side of the resistor to GPIO14 of the Pi and the other part of the LED to one GND pin of the Pi.
For the buzzer, connect the pin marked as + on the buzzer to GPIO15 and the other pin of the buzzer to one GND pin of the Pi.
This is the final result:
To configure this module, we will again use the aREST library, so the code will be very similar to the one we used in the previous section:
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