Optimize data format for wireless communications

[SloMusti]

Data generated by the measurements is communicated wirelessly over Lora or Iridium satellite module.

Values to report:

• Battery voltage 0-4500mV (report in mV)
• Temperature -128 to + 128 degrees (report as value+128/256)
• Ultrasonic range 0-10000mm (reported as raw erading)
• Other variables.

Best is to avoid floats and thus the following scheme is proposed.

• 2 bytes - unsigned integer - number of measurements
• 2 bytes - unsigned average value
• 2 bytes - unsigned min value
• 2 bytes - unsigned max value

Min/max can be dropped if more measurements need to be reported.