Soil Moisture Board #4: OLIMEXINO-32U4 + MOD-nRF8001
This board is almost equal to the RedBearLab board (board #1), but has the following advantages:
- The Arduino board is open hardware.
- It includes a Li-Po charger and regulator. Current draw is easy to measure with the 3.3V/5V selector pin header.
- Much better low-power design. All LEDs can be disabled by cutting traces.