Found out my old GCSE Electronics project today. A trip down memory lane.
It’s my first and only actual electronics project that i’ve built. Aside from those basic ones they showed you at school. As a youngster I was an avid reader of Everyday Practical Electronics so I was very familiar with PIC microcontrollers. When it came around to our final project I couldn’t resist making a kick ass alarm with one. It has four sensor zones (each with anti-tamper). A bellbox can be connected up with a siren, anti-tamper and a strobe light (though I only ever built the main controller). A keypad is used to arm and disarm the alarm (with a 4-digit code). An LCD shows the current state of the alarm and also doubles as a clock!
The firmware was written in an simple assembly dialect. It had a primitive mainloop that allowed it to control (in software) the pulsing of various outputs (internal buzzer, siren and strobe) whilst still responding to the keypad and updating the LCD.
I even had grand plans to build it into a “smart house”, using two free I/O lines to create a serial interface to a controlling PC.