433 mhz RF comms using external AVR MCU (advice on serial protocol needed)

Yes, I'll get hold of some of proper receivers - that should help a lot. Once I figure out how to get compiled code running in an irq working reliably, Espruino should be able to handle even the garbage coming in pretty well though.

I actually spent a while yesterday with this: https://github.com/gfwilliams/RadioRecei­ver

Trying to get it to decode AzzyRF. Not sure if I'm doing something wrong, but I had no luck at all - I guess it's possible it's just a bit too fast for the cheap receiver + audio input :(

If it helps I did this (rough) code for transmission from Espruino which seems to do about the right stuff - albeit without the actual packet formation:

function transmit(pin, data, callback) {
  var pulses = [];
  // 30 training pulses
  for (var i=0;i<30;i++)
    pulses.push(0.2,0.2);
  // 2ms delay off after training pulses
  pulses[pulses.length-1] += 2;
  // output data, MSB first
  data.forEach(function(byte) {
    for (var b=7;b>=0;b--) {
      // on for 0.55ms if 1, 0.3ms if 0, then off for 0.42ms
      pulses.push((byte&1)?0.55:0.3, 0.42);
      byte<<=1;
    }
  });
  // make sure we end on a low signal
  pulses.pop();
  // nowstart pulses
  digitalPulse(pin,1,pulses);
  // work out how long to wait for and call callback after  
  if (callback) {
    var msecs = E.sum(pulses)+2;
    setTimeout(callback, msecs);
  }
}