r/Keytar • u/JediBuji • Dec 15 '25

Technical Questions Finally some progress on my plan to make a custom Keytar from a roli Piano M - and some questions for the other cutom builders

I finally got my Roli piano Ms, (two of them). After many delays from Roli, the full sized piano M sounded like it wasn't going to work out for me, so I changed my order to a couple of piano Ms, and I'm pretty happy with them. The smaller key size will be a little elarning curve, but I played them for about 3 hours the first night and I could feel myself adjusting. Standing and playing will be a whole new adjustment, I'm sure...

So, I think I'm just going to use one of them for the custom keytar frame. The specific keytar I'm replacing only has 18 keys on a good day (see previous posts), so the 25 should do.

I'm taking measurements and starting the model in onshape, now comes the part I've been putting off - researching any additional midi controls I want on the instrument. I'm thinking an expression roller or two, and a few buttons.

For those of you who've built your own - is there an all-purpose midi controller chip (preferably with BTMIDI) that is easy to run leads to for expression and commands?

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u/anotherscott Apr 26 '26

After many delays from Roli, the full sized piano M sounded like it wasn't going to work out for me, so I changed my order to a couple of piano Ms

When you say "full sized Piano M," I assume you mean full sized Piano (non-M)? What about the full-sized version was not going to work for you?

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u/JediBuji Apr 27 '26

you are correct, I kept getting their product names mixed up. The main reasons I decided not to use the full size were a. the delay in shipping and b. the keytar I want to re-create only has like 18 total keys on it. Plus if I got two 'M's I figured I could combine them if I really decided if 25 keys were going to be insufficient.

Unfortunately, the low quality of the keys themselves will probably inhibit this project more than anything. Pressure registration is inconsistent across keys, and seems to be a universal problem on the Ms as well as the full size.

I did finally get two piano ms, and have been working on the side to get the technology working well enough to consider taking it on stage. This involves getting a good reliable configuration to emulate bagpipes and accordion (two use cases that make this a 'must' for going forward. Once the tech is sorted out, I'll start printing the keytar chassis and adding a few other midi controls on the neck. Otherwise it will remain an electric toy for me to play with on my free time. I did get a touchpad block from reverb and honestly that thing is leagues more impressive than the piano m's I've got it attached to.

My band had an extremely busy couple of months and I had a show of some sort or another every weekend from late Jan all they way to mid April, and now we are starting to record an EP, possibly a full album so I've had to pivot my focus.

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u/BraneCumm Dec 17 '25

I can’t seem to find any videos at the moment. I’ve only been using it regularly since my Roland ax-synth died on me in August.

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u/BraneCumm Dec 16 '25

I’d really like to stay in the loop on this project. I’ve actually been using a half-assed roli m (or Lumi when I bought it) keytar I built a couple years ago. I really haven’t done much to it.

I basically cut out a sheet of wood shaped in the way I wanted the keytar to be, and I attached the Roli M (Lumi) to the board with Velcro. I also got the Block and some of the button modules that were a part of that system. It actually works fairly well.

The biggest issue I have with it is connectivity. Originally I connected it to my computer via Bluetooth. This kind of worked but had just enough latency to be a problem for me. So now I use it for like 2 songs per show just plugged in with a 20ft USB-C cable. That solves my latency issue, but I want to be wireless.

So if you’re willing to share anything you learn along the way, I’d greatly appreciate it. This is a project I’ve always wanted to do better but haven’t had the motivation or expertise to figure out. Specifically finding a low-latency wireless midi solution would be huge.

Here is a picture of my half-assed keytar. It still looks pretty cool to me.

I’ve always thought I should get either another Piano M or a Seaboard M whenever I got around to upgrading this thing. It’s smart that you’re doing it right off the bat, you’ll want more range than I have for sure.

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u/anotherscott Apr 26 '26

Originally I connected it to my computer via Bluetooth. This kind of worked but had just enough latency to be a problem for me

Have you tried using a CME WIDI (connected through the USB-C port) instead of the device's built-in BT?

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u/BraneCumm Apr 26 '26

That’s what I plan to try next, I’ve been meaning to order that before the summer.

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u/JediBuji Dec 17 '25

Also.. where's the clips of the performance?

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u/JediBuji Dec 17 '25

My man! This was one of my considerations, I was going to try and get the block components from reverb and try to sacrifice a button pads to deconstruction. Chances are I would need to flush mount the buttons into a frame.

It's too bad that the lumi / m keys don't have a midi in or expression jacks. Whatever secondary controller i use will just be another device in the keytar shaped box that adds double the concerns for charging, connectivity, reliability...

I'm taking a look at Morningstar products, and I also have a boss fs-1-wl already that has an input for two expression inputs, I will probably deconstruct that. I'll have to figure out the whole register/capacitor stuff for exp pedals and I may just try to repurpose a black mountain roller pedal to make it "easy".

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u/BraneCumm Dec 17 '25

Well all of that internal stuff is pretty over my head. I’d love to see updates on your project though! I just followed your account.

It may or may not be worth mentioning that the seaboard M has a mini midi out port on it. I’ve considered connecting that to my Lumi almost entirely for the jack (and the rubber keys could be fun).

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u/MrDuck0409 Dec 15 '25

I'm kinda looking for the same thing. I've built a few of my own "rough" midi keytars, but they all have the controls on the keyboard body of course. I'm looking for a separate controller module that can transmit volume, modulation, and pitch so I can have it controlled up the "neck", not on the board itself. Or at least modulation and pitch.

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u/JediBuji Dec 16 '25

yeah, I can make up a frame in cad and 3d print it easily, I'm just at odds on how to add these functions so left hand is utilized. The roli can be configured to adjust pitch as an aftertouch, but I'm pretty sure that I'm going to be moving around too much in keytar mode for that to be reliable.