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Monitor Battery Voltage At Remote Site

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, 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.



  • Not sure why nobody ever commented on this as it is a brilliant idea. Are you using it in practice? Additional info? How is it working?
  • Although we ran this for a while, the site Greg mentions has been using APRS in recent months instead. This has an advantage that it is out-of-band signalling and persists even if battery system goes below that which keeps the Kiwi and IP link alive. I also added a couple of temperature of sensors for the site, other sensors could easily be included since this is also Arduino.!call=a/N6GN-2&timerange=3600&tail=3600
  • I've often wondered if it would be useful for the KiWi to be able to present a simple webpage in place of the existing top bar which has limited formating options.

    Perhaps this could also allow content from other sources to be embedded in the page.

    This may allow folks to provide more detail about the KiWi config and include other dynamic data such as telemetery, weather or perhaps even a webcam / video feed to be inserted.


    Martin - G8JNJ
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