Rackmount 19" Shruthi 2U Prototype

First of all: Have a nice 2014

I wanted a rackmount shruthi and overall sound tweak control, but all solutions for now were not suitable enough for me. This is what came out!
More Infos on this website (@pinchettes: I didn’t want to spam the forum with too many images. But i will if you want.)

Started with an height of 3U i compressed the layout for fitting into 2U and, yes, it fits! (very tight though but it fits). The layout is made in Illustrator, i can provide you that, but it has some errors, i should rather fix it first.

I altered the shruthi kit a little: buttons and display are plugged to cables, because of the compressed 2U layout theres no space for a upfront mounted shruthi. So now the shruthi is lying inside atached the case.

Then the real nerdy stuff has begun: I took an Arduino, built an Multiplexer, used/customized the multiplex library, built an midi interface for the Arduino, used/customized the midi library (3.0 beta at this time) only to realize that this isn’t working for good: the timing of the knobs while merging signal from the external sequencer was crap and there is rather no chance to fix it. Months later (yes, i have also a job. and a wife) i bought a simple midi merger for less and removed the midi merge code from the arduino library and the whole thing worked. btw the guys in the arduino forum are very nice too!

The power supply (simple Wallwart) provides with an added voltage divider for each the shruthi and arduino a different voltage.

What else to say? Maybe finally after all i would really like to make a nice professional aluminum faceplate without colors or monochrome… and maybe better replace the ugly arduino part by a doepfer usb64 or something. Or any other idea?

wow that looks great!

If the arduino part works as expected, then I don’t see the reason for upgrading it to a DOEPFER solution, since I bet you that would be more expensive, for not a whole lot of improvement.

Nice case :slight_smile:

If you want to get rid of the Arduino part, just flash an Amtel and put it on a protoboard. If your Arduino has a DIP Amtel, just buy a new one, upload the program, and you are done.

That looks just totally awesome. Nice work! Although I like monochrome I think you should stay with this design. How’s that panel made?

well done.
instead of arduino/odther external logic and controlling with midi you could have build a xt board on perfboard, couldn’t you?

Good to know the multiplexing midi merging control solution didn’t work. I was having the same idea’s for an Ambika controller. Could you explain why it didn’t work?

If you want to change it i also think you’d best build it from the schematics of the XT combined with the original programmer from Frank
Then you won’t have to use any external midi merging solution and the screen will display the parameter edited by the knobs!

Good job!

If you want to get rid of the Arduino I would also suggest to use a fcd72’s programmer pcb.

Great project :wink:

Merci @all!

@janniz: the panel is printed by a common online photoprint service (myposter.de), fixed on 3mm aluminium and finished with a anti-scratch-something-layer, all done by them. There is a tricky part by producing with that layer: they stretch the image file before printing at ~6mm, so you have to keep that in mind by sending them image files and reduce the image by these ~6mm. (sounds complicated, but it isn’t at all). And because the online-service doesn’t produce 19" 2U panels i borrowed a little table saw an cutted the panels for my needs. And produced some more panels for other projects too, of course :wink: And after that: Dremel + sharp cutters + lots of filing for the display.

Lovely work tmk009


@V’cent + shiftr: The selfmade-multiplexerarduinomidi-thing does the job not good enogh: merging and handle midi/cc in with ONE potentiometer works great! but merging with the activated multiplexer (so TWO or MORE pots) does not work at all – the overall timing has a lot of latency, thats why I decided to use an external merger. But even though the multiplexer sends the state of each pot every time it cycles through all the values because of the multiplexer (many times in a second and floods the midi channel. I already programmed it like “send only values whet a pot is turned” but when it comes to multiplexing, this is not working) Maybe there is a fix, but after weeks I found none :expressionless: and i stopped searching.

@loderbast + shiftr: well, yes. to be honest, i never thought about that - i made some working arduino midi projects before and had to try it at least :wink: I’ll have a look at the programmer - sounds promising! I made the faceplate repluggable, so replacing the arduino part is a piece of cake.

“Dremel + lots of filing” = sounds familiar :wink:

There is no other way, isn’t it? :stuck_out_tongue:

Sweet! At first I was really into the idea of desktop modules. But I have completely run out of desk space on which to place all of this stuff. So now I’m back to wanting everything in a rack.

So do I. Let’s buy larger tables first!

Edit: I ordered the very last programmer pcb from fcd72 and give it a try. More updates… Soon™

There we go! I received the programmer pcb from fcd72! Now go order the necessary parts.