Build your own DIY hybrid piano - step seven play it!

If you haven't already, check out the previous steps, starting from whatever you want. Each step has a link to the previous one at the beginning and a link to the subsequent one at the end.

The previous step was putting it together

So it now somewhat works. Why somewhat?

• All notes are wired, but a few don't work. I need to double check cables and I know for sure at least one sensor is gone bad

• Dampers are not wired, so note-off is all over the place (the sw could deal with that, but with a hammer sensor, rather than on the shank, if I tune it to be able to do both it does both sloppily, so I will wire the damper sensors which I have installed already )

• Pedals are not wired yet (I just hardset it to always sustain)

• Firmware is not tuned for this action

  All of this is "yet": all of them will happen soon. For now, enjoy some music!

https://www.youtube.com/shorts/jXRktEs6JjM

RIP finally there, congrats!

CyberGene finally there, congrats!

Thanks.

Note that the mic was much closer to the hammers than the speakers, so the action noise shows more in this video than in real life (besides the fact that it has a lid which will stay closed most of the time, and that further muffles the action noise)

Yey! It can be done! Stem paved the way, and you are the first pioneer. It is doable… A cabling nightmare, but doable nonetheless. Congrats.

Soon, there will be dozens of StemPianos around us and no one will be allowed to complain about pivot length ever again: "not happy? Get yourself a Steinway and slap the Stem boards and cables on it".

And to be clear, I said it many times but let me say it once again!

I could do all of this (which is not finished) only by standing on the shoulder of the giants, most notably

@CyberGene (the one who made it all started)

@JayKominek (the one who demonstrated it was replicable and with better engineering)

@gzpiano (the one I've "stolen" most from - thank you!!)

And honorable mention to countless others for long discussions of many things, including but not limited to @xooorx @vagfilm @JayKominek (the one I probably bother most with questions), @dore_m, @luns, @n-player, @spanishbuddha, others that have deleted their accounts 😥 and others that I have unforgivably forgot to mention.

vagfilm Stem paved the way, and you are the first pioneer. I

Well, the way I see it is @CyberGene went into the unknown savanna on foot. Jay followed with a vehicle and made a road. Greg paved that road. They were the pioneers. I just went there as the first tourist and suggested to make a few curves a little less sharp and a few hills a little less steep. Maybe I lend a shovel for that.

vagfilm Congrats.

Thanks!

vagfilm A cabling nightmare, but doable nonetheless.

To be sure, I'm nagging Greg to fix the issue. The beginning is here and here. Basically firmware already supports that, the new PCB for the interposer is merged, but requires work and I have no stamina for that (I thought hard if I should have done that or the "holy mess" you see and I decided for the latter -- I can always change to the former should I change my mind…)

So you and others will have it easier 😉 Good thing that you and @Akari have not purchased the ACEs and sensorboards yet, so you can now make a more informed decision: get it what is ready or work/wait for that small step to substantially improve the cabling.

vagfilm "not happy? Get yourself a Steinway and slap the Stem boards and cables on it".

Well, maybe not a Steinway, but you can get a pretty decent (if not excellent) action and a restorable cabinet basically from the dump. (I realized that when I was looking for an acoustic grand).

Sure, the giant shoulders belong to others. The way I see it, CG poked the hornets nest with his brilliant simple approach, and all of a sudden there were a few different designs that aimed at solving the Cybrid problem (the dreaded trimpots). All "I can do better" moments, require a previous "done" moment. Stem completed and generously shared an open source solution. But until someone was brave enough to replicate it in a different action (the pioneer) there was an element of doubt. That hurdle is cleared.

RIP @CyberGene went into the unknown savanna on foot. Jay followed with a vehicle and made a road. Greg paved that road. They were the pioneers. I just went there as the first tourist

I love this analogy ☺️.

Enjoy your hard work!

Cheers,

HZ

What happened with the boards that were using stm32h7** (those had multiple 16bit adcs on them, probably 10-12bit enob?)
What was the end result with those? Too noisy? Too hard to program for?

DavisB Too hard to program for?

Too hard to program for is an understatement 🤣 -- I concluded that those boards are good for industrial applications, but not for hobbyist ones. And frankly I saw no advantages compared to this approach. For details, see

https://pianoclack.com/forum/d/674-build-your-own-hybrid-piano-step-five-the-firmware

In fact, I like this current approach (Teensy with external ADC) for even another reason: it's much more flexible since you can put more CPU horsepower or better ADC independently and without one need forcing the other.

RIP
Do you need to reprogram the boards in order to install it?

CrisOliveira Do you need to reprogram the boards in order to install it?

Not sure what you mean by "reprogram". Let me try to answer by guessing.

The boards (both STM32 and Teensy and all others) come from the manufacturers with demo firmwares, typically just flashing a LED. So yes you do need to "reprogram" them to put a "ADC measuring and MIDI producing" firmware. Probably multiple times since I'll bet you'll have something to tweak to your satisfaction

RIP
I thought you could just upload to it firmware downloaded from Github. But I also wondered if you had to tweak the firmware so it will work with your action. You probably did both, I guess.

CrisOliveira I thought you could just upload to it firmware downloaded from Github.

I see. You might, if your action and sensors are exactly as the author of the firmware. I used different sensors mounted in a different position in the action at much larger distance. So I had to change some parameters (e.g. % of travel at which consider the note played). At the moment these parameters are compile time variables. We can definitely make them some runtime settings that one could change in some way, e.g. combination of keypresses as it is on the old digital pianos, or maybe with a small touchscreen. I am not bothered too much about the recompile-reupload so I did not push much about it. Feel free to suggest it to either or both github repos, I'm sure the authors will consider the suggestion

PS: note that at least for Teensy, you must compile it yourself (just the way their software is set up) so you can't simply download a binary and upload it: you download a source code, compile it and upload it (but you could refrain from changing it)

Just saw and read these posts.

Nice video and congratulations!! Cool!

I play this hybrid piano regularly. Last week I had a group of friends over for piano playing and they all said without question stem piano is much more realistic than any non-acoustic they have played.

Note that I renamed the original repository and it is now called "open-hybrid-piano".

I renamed it (from "DIY…" whatever it was called) because the project is fully open source licensed and being replicated. (first replicated by: @RIP!)

I also have the stem piano repository which is more suited for collaboration because I created it as a GitHub organization. Easier for many contributors. Whereas, the open-hybrid-piano repository is under my personal GitHub.

The names probably should be switched now that I think about it.