Well done.
You have done a very neat job.
I say that through clenched teeth because we were only about a month away from putting our own oscillator out there!
I have been working on this with fellow Z owner Greg Hassen.
I have a rally clock, but Greg has done most of the testing. He has found some variation between clocks so we have put an adjustment knob on ours. To be honest, I can’t see why there should be any variation; the clock runs off a synchronous motor. I do know that the little plastic gear on the rotor shaft has a crack in one or two clocks Greg has tested, and this could be the cause of the variations. The clock I have also has a crack on the rotor shaft gear as well, in fact it is missing a complete tooth! It occasionally stalls and I expect this could be the cause (though mostly it seems to keep going despite the missing tooth, the momentum of the gears might be enough to keep it going). The pulse duty-cycle also seems to have an effect on the likelihood of stalling (I think around 80% gave the best results on my clock).
I say all this because the cracked gear seems to be a common problem. If any of your customers has this problem and don’t realise it, they might unjustly blame your circuit. You should probably have them check the gear before selling them your oscillator, or at least inform them that the problem could exist. Greg has been looking at replacement options for the cracked gear.
I will try to include a photo of my cracked gear. You can use it in your dealings with customers if you like.
I think you have done a very neat job. And having been beaten to it, Greg and I debated whether to continue with our project.
We think we might (it would be very unsatisfying to just drop it after all the time we have put into it, so watch out, you might have some competition on your hands!), and I think we could probably bring it to market for, say, $98.50 ;-)
And if there isn’t much of a market, or you have already saturated it, then maybe would could collaborate instead of compete (I’ll have to consult with our Global Strategic Business Development Manager: Greg).
Eric