John, I thought about that but that was not the idea why I started the project
I decided to make something good for myself first to adopt the idea.
Tempo blinking is done by dedicated micro controller which I have developed over 8 years ago to sync any gear (roland, korg, moog - no matter) with midi clock. it's flexible in options from two bars ticks to 48ppqn, but I have configured it for bar + quarters. The only change I increased pulse length. Obviously I had to solder to one point on the main board (right after midi input opto ic) to connect to MIDI. it doesn't have much soldering space. At least 1mm solder iron and zoom lens are required. I do understand you may be concerned about that. Even it's only one wire, this have to be done very accurately. That's the whole reason why it syncs to external clock only and takes only HW MIDI port.
Color changes are driven by separate controller over the PWM. it's single chip solution + durlington pair to drive hi-power LEDs. it needs to be connected to the central pin of both wheels to enable position scanning. I connected it to modwheel only and works well. But for pitch band it's a bit tricky, I have noticed side effect of Solaris scanning for this wheel. Of course, I have isolated my circuit from on the Solaris circuit (simply by diode
) but this works in one way - I'm protecting Solaris, but not my circuit from it. That could be easily solved by another diode in between potentiometer and Solaris circuit, but I wanted to make minimal changes to existing schematics. will do that some day later.
In total for this feature set I came with 5 connection wires ( +12V, ground, pitch, modwheel, midi).
Thinking about the kit - what features you're interested in? Do you need color change? Tempo Sync? or have other idea to implement?
So, now it looks ugly inside since was designed on prototype board. But there is good place for it under the wheels. So, once design will be completed, I'll make the PCB.
