RIP
Khuja Wangtishvili Was it impossible to use any kind of bus rails to drive all the signals to one place? I was just thinking why to make so many cable connections if there are massive transmission protocols right now.
These are analog signals (hence the importance of twisting to reduce interference). While not technically impossible to reduce the number of cables by techniques such as multiplexing, that would have increased the complexity of the design and possible point of failures tremendously.
Khuja Wangtishvili I do not know how this is solved in mass produced pianos,
The vast majority of digital pianos use switches, directly mounted on the boards attached to the keybed. Not a valid solution for a hybrid with hammer sensors, which moreover needs to adapt to a generic action (which, as I mentioned recently in the "sell or keep" thread, are all different from each other). So forget the "normal" digital piano and consider only the hybrid ones. More on that later.
Khuja Wangtishvili Also wanted to ask, what is the advantage of your system above the optical stripe available from Kioshi, QRS, PNOscan and similar? All of them are just sensor strips put below the action and connected to the sound controller.
I had a NU1 and I sold it. I wanted an instrument with both hammer and key sensors, period. The NU1 was not bad, but it did not give a good "connection" between the hammer movement (which I could feel in the key) and the sound generation (which was created according to the key, not hammer, movement). For some, the worse of this situation is the "loud node issue" (google it). That was not particularly bothering me too much, but I wanted a stronger connection. None of these systems you mention are hammer sensors, and to me they are a moot point, unless installed on an acoustic piano for occasional use or for MIDI capturing of an acoustic performance. Even more moot for me is having a digital piano with full acoustic action and then sensing the keys!?? Like having a car with two engine, one of a Ferrari and the other of a Honda Civic, but you use the engine of the Ferrari just to spin wheels that do not touch the ground. What's the point?
So for me the alternative was another commercial piano with hammer sensors. And to avoid problems with incorrect damping, I wanted key sensors too. So that restricted the possibilities even further. I believe the N1 would have fit the bill, but I did not like its aesthetics and the price was way, way, way out of my budget. For the few pictures that I've seen ( @CyberGene or @David B may have more) it has quite a bit of cabling too.
Khuja Wangtishvili Just trying to understand what your massive work is for, while there are ready solutions (quite costly though).
In conclusion, there was nothing that was satisfying me technically, besides the Yamaha N1 (and friends) at about 10x cost of what I am spending. Plus, if I won't like something of this instrument I'm building, I can change it, both in software and in hardware, so it's fun!
Hope this helps!