Interfacing broken Roland 2900G Piano

aaron235

Hi to you all and thanks a lot for this nice forum.

I need some help. I have a Roland 2900G piano with a complete burned main board (from thunder).

I tryed to look for reparing but it's useless, to many parts to fix… So, I'd like to reuse the 2 straps nice keyboard and interface it with a SBC, arduino or Pi… is it possible ? Any links for doing that ?

Thanks a lot for your help.

Alex

CyberGene

aaron235 Welcome to the forum.

I think if you can power the keyboard and obtain the switch signal from it (I would assume there are double switches under each key), it would be pretty easy to input that into a Teensy and produce MIDI. Not sure someone has made it here but other than that some of the DIY projects here revolve around producing MIDI time based keyboard activations which is what switches will produce, so with a pretty simple keyboard scanning loop you would turn those activations into MIDI velocity.

aaron235

CyberGene Thank you so much for your answer.

I have 2 connectors out of it. I guess someone already found a way to decode those. I can try to understand it myself too but I doubt to have the necessary skills…. A.

CyberGene

aaron235 I have 2 connectors out of it. I guess someone already found a way to decode those.

Probably there is some info on the Internet but I think it's very rare for somebody to gut a digital piano and reuse only the keyboard along with the keyboard controller, so I am not sure how easy it would be for you to find that info. And depending on where exactly along that electronic chain you would like to hook up to (and consequently to what degree you would like to DIY) it might be as easy as to directly receiving MIDI signals out of those connectors, or as hard as bypassing all the electronics there and just use the keyboard mechanically and the rubber dome switches with you implementing the algorithm for scanning the switch activations (when you press a key, those switches will activate in a sequence, so measuring the time between two activations is what produces MIDI velocity). If you decide to go the latter route, there is some know-how. For instance, my own DIY hybrid which is called Cybrid has a pretty simple code that continuously scans the entire keyboard in sequence and from the sensor activations (mine are optical but it's the same they are made to produce binary on/off states) measure duration and produces MIDI, you can see the linked GitHub and code in that discussion.

MacMacMac

Is it worthwhile to put time and money into a thirty-year-old broken piano?

aaron235

MacMacMac it's a real question macmacmac… The keyboard itself is a very good one, heavy and large… I wonder…

Pete14

MacMacMac Is it worthwhile to put time and money into a thirty-year-old broken piano?

Yes, Mac, it is, and how dare you imply otherwise!

I just ‘put time & money’ into my fifty-year-old broken fridge, but I suppose you’d just tell me to “throw that thing away and get a fancy Samsung smart fridge…”

But I’ll have you know that my ‘dumb-old’ fridge can outsmart that there fancy Samsung; and now that I ‘put’ some money into it, it also serves as my safe (no password needed); granted, the cash can get fairly cold sitting alongside my meat, popsicles, sausages, and Viagra (yes, I take a frozen Viagra whence Margarita -my girlfriend- stops by; so sue me).

Del Vento

aaron235 MacMacMac it's a real question macmacmac… The keyboard itself is a very good one, heavy and large… I wonder…

If you really like the keyboard mechanics, which basically means the action, then yes, it's worthwhile. But it will be work, not a quick fix and you have to ask yourself if you want to do that work. Only you can know that answer but the basic point is if you'd have fun doing the work, rather than considering it a chore. If you consider it a chore, forget it, you can purchase on craigslist similar things for couple hundreds and sometimes less or for free.

If you still think you want to do it, here is a nice summary of similar projects you can take inspiration from: https://pianoclack.com/forum/d/745-summary-of-digitalhybrid-piano-diy-projects

SouthPark

It will probably be a long road - a Rambo long road. But can always try - to see where it leads. The first step is probably to see how the timing mechanism is 'meant' to work - as in find out what their design is -- that allows them to get key velocity reliably - without glitches. And their method to know when to reset the timing system in order to prime it for the next measurement - and to be able to measure the next key strike - without glitches.

Also noting that more modern systems are getting into three-pad scheme for each note, instead of two-pad. Yours will be two-pad -- which will be less to deal with (in the measurements and programming side of things).

CyberGene

Look through this excellent doc to get an understanding of how scanning a keyboard works, in this case the VPC1, as reverse engineered by Jack O'Flaherty in 2014:
https://web.archive.org/web/20170107103139/http://joflaherty.org/VPC1/VPC1KeyboardScanning.pdf

aaron235

CyberGene Waou, thank you so much for those datas and infos. I see the journey you went thru and your knowledge and experience will surly help me ! I think I'll try to give you some news around here. Thanks agoin ! Aron

aaron235

Del Vento Thank you so much for your answer. Reading those docs I understand the level of work that I would have to search. Anyway, I'm going to test few things and give you some news here if you're interested…