Ideas for the next revision of the PCB

[dajtxx]

More ground terminals.

It looks like the following pins are free, so see if they're usable:

4, 5, 7 are input only as GPIO 35, 36, 39. These are also available to the ULP so might be good as level or edge triggered inputs. These pins are on the top of the module.

17, 18, 19, 20, 21, 22 are GPIO 6 - 11, input and output so could be used to drive something. These pins are on the left side of the module.

None of the above seem to be bootstrapping pins.

[dajtxx]

Add a DS18B20 temp sensor. Or an ADT7410 - that won't need any extra pins because it goes straight onto the I2C bus. Exploratory work with a breakout board and bodge wires shows it is simple to integrate.

[dajtxx]

Remove the piezo buzzer?