That's pretty neat. It doesn't seem to hit the days or months of use on AA batteries constraint. That said, I didn't consider the ESP32 line of SBCs and now I'm looking into low power variants so thanks for pointing this out.
If you want low power, try the nRF52 series of chips (e.g. nRF52840). Much less power hungry than the ESP32 with a comparable ARM core. Only Bluetooth though - no WiFi. nRF52840 sensors can run for months on a single CR2032 coin cell, and the power consumption while running is lower too.
