My local volunteer supported library likes to keep track of the level of footfall traffic each day. So far, the numbers of Adults, Teens and Children has been recorded on paper and entered into a Google Sheets spreadsheet where a bunch of analysis is done.

In a moment of weakness and alcohol, I offered to make an electronic device to do this. It needed to be a robust and cheap solution, and I didn’t want the bother of any new cloud infrastructure to support it, so it had to write to Google Sheets directly.

Fortunately, MicroPython-GoogleSheet is a Micropython package that does exactly this.

I chose the ESP32-C3 Super Mini as a board. This has a 32 bit RISC-V processor with WiFi, Bluetooth, 400KB of RAM and 4MB of flash memory. At the time of writing, it’s selling for £1.70 on AliExpress.

Although I could have just written the software as a simple main loop, I used python asyncio as that allowed me to have a couple of co-routines running as watchdog and network timers to reset the device if it got stuck too long or lost network connectivity.

The led does a little traffic light display, red is offline, green is online and ready, and yellow is working on registering an entry.

The body of the case was designed in Fusion 360 and printed with my Creality CR-10S in white PLA and the front and rear panels cut from black acrylic with my homebrew laser cutter.

Nothing too clever about this little project, but I think the physical design looks nice and it does show what a great age this is for the home builder with tools and components like this available for very low cost.