Fochica is one of the twenty finalists in the Hackaday Prize, Best product category. One of the requirements of the competition, which is unique to this category, is to submit 3 prototypes for judging.

For this round of prototypes I have decided to try another build layout using Arduino Nanos. Previously I posted details about builds on a breadboard or builds in a form factor of an Arduino Uno shield, but this time we are going for a record small and low-cost build.

Some technical differences of this build from the previous ones:

• Driving the buzzer directly by a GPIO pin through a resistor, removing the need for a transistor;
• Moving power functionality to an off-the-shelf module that is off-board;
• Switching to capacitive pressure sensors instead of capacitive proximity plus buckle reed sensor combination for seat occupancy detection (worth a separate build log)

The schematic is not significantly different from previous builds, but the layout is completely new.

The Nano board and BLE module(s) are on top of a 20x14 hole perfboard.

The build is not extremely complex, as there are just a few components. It is challenging because it is on a perfboard rather than on a custom PCB, but I am not sure yet if this is going to be the design going forward and I didn’t want to wait a month for PCBs just to save an hour or two of work. So after some careful soldering:

I got a new batch of prototypes. Which look awesome IMO:

Three of these devices are now on their way to Supplyframe Inc in Pasadena, CA. Crossing fingers and hoping at all arrives on time and in one piece.

I would like to thank Hackaday, the organizers of the competition and the sponsors for the wonderful opportunity.