Running a remote KiwiSDR off grid? Want to monitor your battery voltage on your solar/wind system? Don't want to or can't use APRS? A simple voltage divider and an Arduino can measure voltage, format Morse code messages, and on/off key a small TTL "can" oscillator. Use the Kiwi to listen to the oscillator. I used a 10 K ohm and 100 K ohm resistor for the voltage divider. (Maximum input voltage on Arduino Uno analog pins is 5 volts. Edit the code if you use different resistor values). I used a contrib Morse code library from https://github.com/willvincent/ArduinoMorse
, and merged code from a couple of other peoples projects. I have attached the code as a file attachment. In my testing I used a 10 MHz can that I happened to have, listened on the 30 MHz harmonic, and didn't even have to add a short antenna to the can.