In order to be a worthwhile device to log any sort of data, it will need a few properties:
1. Data storage (EEPROM or µSD)
2. Power Management (Battery and/or solar)
3. RTC for timestamping
In an effort to make it easy/cheap to fabricate:
1. Limit to 4 layers (preferably 2)
2. No custom parts (except PCB)
3. Limit the number of very small parts (eg 0402 components).
In an effort to make environmentally safe:
1. Use only RoHS components/techniques
2. No lead/halides or other dangerous chemicals
Hi! You could probably enter #The Square Inch Project with this if you'd like to :)