Radio node mini

There is now new basic sketch on GitHub that can be used as basis for integration of mini node to OHS. It registers 3 sensors, that is: battery voltage, TX power level and charging state. Sketch can be uploaded using Arduino IDE and selecting Arduino Pro Mini board, be careful to select proper crystal speed(16 or 8MHz) when uploading the sketch. Voltage selection in menu of Arduino IDE can be ignored as board works always with 3V3.

Just now I realized the board size is pretty close to standard SD card.

Also I will be mostly using simple wire antenna with this small boards. Here are length of wire that can be soldered directly to RFM69 pad:

433 1/4 wave = 164.7mm
433 1/2 wave = 329.4mm
433 full wave = 692.7mm

868 1/4 wave = 82.2mm
868 1/2 wave = 164.3mm
868 full wave = 345.5mm

915 1/4 wave = 77.9mm
915 1/2 wave = 155.9mm
915 full wave = 327.8mm

I personally use 868 modules and 1/4 wave length antennas.