A new version of the Opera software has just been released which can output the bit code of a beacon signal so it can be programmed into a microcontroller such as a PIC or a Parallax Propeller chip. (You can find the download via the Links page of the Opera Yahoo group.)
I modified Eldon Brown WA0UWH's QRSS program code to send the bit code generated by the Opera software and it was received by my K3 on 30m and successfully decoded. Not bad for 5 minutes' work! You can download the code here.
Just as Eldon did I will have to build an amplifier to raise the output of the Propeller from a couple of milliwatts to something with a better chance of being received. Before it is worth doing that people will have to start using the Opera mode on the HF bands because with my antenna restrictions I have no hope of receiving or radiating a signal on LF or VLF. But I am quite excited at the possibility of building simple standalone beacon transmitters for this new weak signal mode which is much easier to generate than WSPR or QRSS.
Stop press: Just decoded G0NBD on 10.135MHz +1500Hz for my first real over-the-air Opera spot. And it appears my first transmission (using the PC software and my K3 at 5W) has been received by OM5NA at -21dB. This is fun!