HumTempNode

Small and easy to build MySensors temperature and humidity sensor based on BlackCircleSensor.

Extending the Arduino's Battery life

To be able to use the arduino with a coin cell battery, some steps are needed:

• Burn 1MHz ATMega328P 1MHz Bootloader with 1.8V BOD from MiniCore.
• Unsolder on-board voltage regulator and power LED (You can keep the built-in LED in pin 13, it's useful for debugging).

For this sensor I used the 5V variant of the Arduino Pro mini, but the 3.3V one should work as well (Maybe even better!).

Software

• Modify the provided sketch to your liking (Static node id, battery level reporting...).
• Upload the sketch to the Arduino without the coin cell battery inserted.
• Unplug the Arduino from the FTDI cable and insert the battery.