Motion Sensor Alarm System – The Big Idea

Team Super Saver began work on laying out the hardware that would be required to build the Motion Sensor Alarm System. We experimented with the individual components to learn exactly how they worked. Our plan was to create a system that used a motion sensor to detect if a person was passing by, which then set off an alarm. If that person had the correct key fob, they could disable the alarm when they walked by.


Starting with the PIR Motion Sensor, we wired it up directly to an LED and resistor in order to test its timing and sensitivity settings. We learned that by keeping the timing dial and sensitivity dial at their minimum values, we could light up the LED most accurately with when we activated the motion sensor. Next, we test the buzzer.  We learned that the buzzer would not receive DC voltage, only taking AC.  This somewhat complicated our project, as now we must send a Pulse Width Modulation from the A3BU to the buzzer in order to trigger it, as opposed to just a DC signal, like the rest of our equipment runs on. Finally, we attempted to test our RF Receiver.  We were able to set it up but found that we never ordered a remote transmitter… So, we quickly placed an order and continued to set up the rest of our circuit. After that, we decided to break for lunch, and Gabe, who was in charge of coding the A3BU, had to leave. We the rest of us returned from lunch, we decided all that we could do for the day was clean up our board and draw schematics for the circuitry, in case something happened.

UPDATE: 12/9/17:

After realizing the RF Transmitter would not arrive in time for the projects deadline, we decided to remove the RF Receiver and RF Transmitter from our plans entirely.  Instead, we decided to build the interrupt to our buzzer directly into one of the A3BU’s Buttons.