yes the PCB works, I have assembled one and tested it for basic function (not all buttons and leds) but I have stability problem that comes from the software, I put it aside to do other things and didn't have time to go back to it, if there is some interest for it I will find some time and finish at least a basic script.
The node is a very simple one. So I never considered boot loaders, as the node would not need changing sketches during it's lifetime. I have boot loading functionality on my other designs, this one is a minimal board. Any extra chip would beat the purpose of the word "minimal".
It's a dumb node for a reason
I'm thinking about upgrading this board to include pinout for LIS3DH breakout board, like this one :
and ditch the ADXL shield as it's not a good solution, it has either the ADXL345 which uses too much power, or the ADXL362 which is ultra low power but lacks advanced functionality like tap/double tap detection.
I would like to have feedback of users on this (do it sound useful ?), and also know if anyone uses the SMD footprints on the board, for leds and for reserve capacitors, as it could be a cleaner board without those footprints.
I would make the following changes :
put footprint for LIS3DH accelerometer along the "NModule connector" as it has too many pins to put elsewhere
keep only one I2C footprint on the side, for "GY-49" MAX44009 light sensor breakout board: https://www.aliexpress.com/item/GY-49-MAX44009-Ambient-Light-Sensor-Module-for-Arduino-with-4P-Pin-Header-Module/32828654450.html
temperature/humidity would be via the existing "SMD" footprint, it's not through hole but very easy to solder as it's 2.54mm pad spacing
remove SMD footprints for LED, add footprint for through hole reserve capacitor, keep SMD footprints for reserve capacitors only if I have space for them
shield would be a bit extended to go over the 2 M2 holes in the "power" part of the NModule, so it could be fitted with spacers and nylon screws and have stable/reliable mechanical connection between NModule and Shield. Basically this would be the footprint of the shield :
So in the end it would make one shield to have Temperature/Humidity/Light/Acceleration or Temperature/Humidity/Light/Door.