The Shruthi-1 Programmer - FINAL EDITION SOLD OUT!
  • Here it is: the Shruthi-Programmer expanding Shruthis User interface to 32 Knobs, one for each Synthesis Parameter:

    First, let me thank Olivier for his kind cooperation and help on this one, he was so gracious including the needed Software in the upcomming Firmware Rev 0.92 and added the needed connecor to the Digital Board Rev 0.7 to make this work. Again, thanks a Zillion times!!

    Now to the facts: this Programmer has 32 additional Pots, one for each Synthesis Parameter of the Shruthi-1 (Osc1, Osc2, Mixer, Filter, Env1, Env2, Lfo1, Lfo2). Nothing more, nothing less. It docks to the Output Expander Port on the Rev 0.7 Digital Board. If you have an older Board you can well solder the connecting cables directly to the board.

    How does it work: Shruthi’s onboard LEDs are driven by 74HC595 Serial in -> Parallel out Shift register, that easily can be cascaded. The Output Expander Port replicates the Power and Clock signals used and provides the Serial “Overflow” of the onboard Shift Register. On the Programmer Logic Board a second 74HC595 is used to demultiplex 5 more bits that simply are pushed thru the onboard register, 3 of them used to drive 4051 analog switches and 2 to be demultiplexed by a 74HC137 for selecting the 4051s.
    The 0V…5V Signal is generated by a 10K lin Potentiometer used as a Voltage Divider, fed thru the 4051s to Shruthis CV1 in.

    Here are the schematics as .pdf.

    Here is a Pic of the Backside:

    While this Prototype is in a Beta Stage a few things will have to be optimized:

    On the Software side the Code for driving the Programmer is only allowed to use excess computional Power of the ATMega, which is not very much, depending on the Patch you are playing. Sometimes the update Rate gets a bit low for heavy double handed live tweaking but for programming needs its just perfect. Maybe some Optimization here can be done.

    On the Hardware side I plan to do a PCB or Kit if there is enough interest, so i need your input to determine

    • if you are interested in a PCB or Kit?
    • if you prefer a big PCB with a standard Layout for Pots and then: what Layout?
    • would you like rather a smaller (hence cheaper) PCB and go with your individual Layout and Panel-Mounted Pots?
    • or do you want a big PCB with prewired Pots and Patch Points to do your own assingin on a standard Grid?
    • is there interest in the Blacky Enclosure for the Shruthi + Programmer?

    Any suggestion is welcome!

    Ah, and more Pics and Videos will be posted here .

  • wow wow wow!
    This is wonderful!

    My ideal would be a kit that I could attach my own panel mount pots to-
    But I would be interested no matter which way things go.

    Great stuff fcd72.
  • excellent! beutyful!
    i would love to have one of these! but will it work with the older shruti?
    if this is possible i would like to go with the smaller pcb and individual layout.
    kit would be perfect!
    would it be possible to use just one strip of these for perhaps just the filter-section?

  • I think I just fainted for a second…
    this is gorgeous!
    you have my love! :D

  • just what i need! yay
    count me in please, pcbs if you like to offer some…

    1 question, could i use this one control surface for several shruthis by switches/buttons? although it might be cooler to have 1 shruthi and 1 programmer as 1 unit.
    anyway, great work! and a nice case too, btw

  • Grrrrr 595!!!! Lol….welldone dudes :)

  • Thanks guys!

    Its built for the Shruthi and since the Shruti has even less computional power i dont think you can make it work, even i you find someone to modify the firmware so the answer is: No.

    The Shruthi docked to the left has the standard layout and the standard knobs, see here although they are not that good visible in tne b/w Pics.

    Shruthi reads the pots all the time, if you switch them away it reads a random value or whatever you switch the 4051s input to, so unless you disable the Programmer in the System Pages its not a good idea to disconnect it. So i’m sorry, the answer here is: No.

  • VERY cool! Nice job.. Presumably that would work equally well with polychained Shruthis? (I don't think this is the same as rosch asked?)
  • Congrats to fcd72 for this awesome job!

    To bring a few more technical points:

    • As fcd72 said, this uses some spare machine cycles so the refresh rate can be slow on complex patches. fcd72 is going to send me a proto so that I can profile the code and see how to improve the performance, if possible.
    • This “hijacks” the pot scanning mechanism, so this is very Shruthi specific: it needs some specific code in the firmware to work, and its design relies on the way the I/O is done on the Shruthi. This is a very low-level approach to the problem – a more generic and flexible (but $$$costly$$$) solution would have been to do a dedicated MIDI controller with a MIDI merger. But with MIDI you can’t enjoy the elegance of making something über-cool with six 7400 series chips.
    • The programmer needs to be supported by the firmware. In the firmware v0.92, there’s a new option in which you decide what the 4 CV inputs are used for : existing behaviour (4 CV inputs in modulation matrix), programmer, or CV1/CV2 hardwired to osc1/osc2 params for VS-like joystick operation.
    • Parameters changes are sent as MIDI messages, so they are forwarded to slaves in Polychaining mode.

  • @fcd72: have you tried disabling MIDI thru/forwarding of CC (MIDI out mode: “off” or “thru” instead of “full”). This might give you a performance boost.

    I have rewritten some code handling the ADC conversions to have them run in the background instead of blocking any non-audio code during them, maybe this will provide a sufficient performance boost. Can’t tell until fcd72 sends me a programmer :D

  • @pichenettes
    Programmer Logic Board (and the MUTAMP 4474s) is on its way since Thursday – i assume you have enough pots ;-)
    And YES!, turning MIDI to off seems to double Performance!!

  • Since i do a “reverse engenering” of an Edirol controler board i saw an intersting thing. They filtering analog pots and slider with capacitor, and so no need of software filtering wich could be a good option for speed improvment.

  • Thats bloody awesome.

    I might be interested in a kit; id be interested in a full case for both the shruthi and the programmer.
  • @eatyone: this will remove some noise, but I think the main contribution of the noise comes from the ATMega ADC itself!

  • wow!
    i’d be interested in the easiest version to build and connect ;)
    great work!!!

  • :O

    That’s incredible.

    I want one. My girlfriend will kill me for abandoning her yet again to spend the weekend soldering stuff, but I’ll work something out.

    This is where I’m coming from:

    • If there’s a kit available, I’d buy the kit. If you just want to make the PCBs (and case?) available then that’s cool too, so long as the parts are easy to source.
    • I dont much care about whether the pots are mounted on the PCB or on the panel, although I suppose on balance panel-mounted is better because it’s cheaper and allows people more flexibility in building their cases. What I do care about is the case. I’m crap at building cases for things so I’d love to have an option to buy a case with engravings for a standard layout.
    • I’m interested in how “Plug & Play” this is. For instance, if it came with a Blacky enclosure, would I also have to put the innards of my Shruthi into a Blacky enclosure, or could I somehow modify the current perspex enclosure to allow this unit to be plugged and unplugged easily?
  • @ElectroDruid

    Indeed the parts are very standard and should be no problem at all to source. You can easily upgrade Shruthi Digital Boards with a Revision lower than 0.6 with the needed Hardware Expander Port, it a matter of soldering 5 connections (actually the proto is connceted to a 0.5 Board) and you don’t have to buy a Blacky Case – inside its exactly the same formfactor as the standard Plexi Case from Mutable Instruments (i hijacked the schematics ;-) ). For now there is no standard Plug/Connector for the Programmer so its up to you what to choose and how Plug and Play this will be. Attention! Quirks Ahoy! You will have to disable the Programmer in the Shruthi System Pages when disconnected or else its reading random Noise from the not existign Pots….

  • Outstanding work.

    As far as boards go, I would much prefer one with PCB mounted pots, that will make the case much easier to build and make the board easier to mount. Plus if anyone wants to hand wire and panel mount the pots, that is already done since pots are on 0.100 spacing anyway so those ppl can just put a header there or solder wires directly the PCB..

  • On the positive side PCB Mounted Pots are cheaper, on the neagtive side the PCB gets quite large hence expensive. I will have to calculate this, if its nearly equal i’ll do the “SmalL” Version with panel mounted Pots.

    Here are some more considerations from my side:

    • I wont do different Versions of this as i do this as a hobby and i am quite limited on time most of the year.
    • If i do the “Big”-PCB Version it will definetly have 2 rows of pads, one for the inputs and one for the Pots so you can Patch your own Layout to the defined Grid (or just bridge the pads 1:1 to get a standard Layout.
    • wether it will be the Big or Small version, I will do complete Kits as i don’t see the global advantage of everybody wasting time on sourcing parts and paying shipping costs twice.
    • there will only be one standard Case for this, presumably based on the Black enclosure
  • Wow, this is amazing. After seeing this, I have to buy a shruthi-1 as well. I already have a shruti-1 and didn't feel the need of buying the shruthi-1, but this hands on control makes it completely different.
    Well done!
  • How are you planning on dealing with the position update on the pots so the values dont jump between patches? If each pot will update the value on the screen, then a midi control style “catch up” (i.e. pot does not do anything until it physically reaches the right value) may be an easy solution..

  • Nice work fcd!!!

  • Wow nice. I’m interested. I usually just buy PCBs. I learn alot from sourcing my own parts, but kits are great, too.

  • Take care, u’ve got an AD on Noisepage :)


  • @altitude

    Nothing happens when patches are switched until you move that specific button. I dont like the “snap” mode as it does not provide instant feedback – everytime i touch a knob like this i tend to think the machine is broken ;-). For now the values are not shown onscreen (but available via MIDI which makes the Shruthi a great controller for CC00-31…), we are discussing that topic in respect of visible feedback when tweaking bothhanded and available machine cycles.

  • i hope no one construes what i’m about to say as negative, but is the programmer really a kit that people would buy?

    the shruthi is a cheap fun synth project. it shines because you can get nice sounds out of it. is there really a market for this in kit form? does a cheap lo fi monosynth really need all it’s parameters broken out fully? especially when most are available via cc and more still by nprn.

    fcd72, this is not to take away from your work, because it really is impressive. just my thoughts on the kit, if it comes to be.

  • The kit itself will be cheaper than the Shruthi hence cheaper than most external controller, as far as i can see. You are right, the Shruthi as it is is well accessible and programmable, but trust me – having 1 knob per parameter is a whole different ShruthiVersum™. It’s my first 1 Knob/Parameter Synth and before making this work I also didnt get the real magic of that concept. Now that I have one i have a few things to sale…..

    To answer you questions; Yes, there are people interested, see above. Yes, it deserves although its cheap it is a marvelous sounding, flexible and easy to understand machine and there are people who prefer hardware over software and do not want to program a patch for a nondedicatet controller because this is as sexy to me as using a VA-Plugin (near negative sexyness factor…unless you programmed it yourself ;-) ).

    To put it another way: “Its all about hardware, Dude” ;-)

  • ok, good luck with it!

  • To fcd’s point, Livid Instruments makes a great MIDI controller with 32 knobs that could be used but it’s $500.

    For those of us with multiple units, could we use more than one unit with the controller or would we have to wire everything together during construction of new units?

  • @CheeseNoOnions

    The Programmer is connected with 6 Wires to the Shruthi, so its easy to use a connector to your choice and use the programmer with multiple units (although personally i would Polychain them). Don’t forget to disable the Programmer in the System Pages when disconnected.

  • hi

    I appreciate its really early days but do you have any idea about when this may become available?

    It looks like a very desirable addition. I have actually started building my shruthi yet, so if this isnt far off it might be worth waiting for. If its 6 months or so plus, it might be worth getting another kit in later.

    I assume it supports all the filter board options?

    Many thanks, ben
  • Hi Ben,

    my schedule is havin the Kit ready for early January. As i have absolutely no experience with designing PCBs this might change ;-)
    It works with all filter board as it does not touch them, you only have to add the OutputExpander Port, which the new boards with Rev 0.7+ will have, thats a matter of soldering 6 Wires. If you managed to build a Shruthi this should be abolutely no Problem for you.

    If you cant wait till the kit is available, you can easiliy build it from the schematics

  • Im in no rush at all - only built one thing in my life, which isnt 100% right, so need more practise before i start on anything valuable. While im building it would make sense to do it all in one go anyway.

    It all depends on how you decide to make it - an all in one case for shruthi+programmer or just a case for programmer. An all in one solution (as kit form) would suit me best personally ...

    Cheers !

    edit - looked at the schematic - another 4051!

  • Hey fcd72,

    I have an odd question. I have an SSM2300 that I got when I sourced the CEM3379. I was wondering if if could sub it for one of the 4051D’s in your schematic. Here’s the datasheet I guess my real question is whether I should even use this chip for anything. It’s not a VCA or VCF. Do you think this chip could be useful in anyway that the 4051 wouldn’t? Thanks.

  • The SSM2300 is a super-helpful chip for polysynths – it’s a 4051 with a sample and hold on each analog line! You’d better keep it for another use – it’s way too overkill for this application. Heck, even a 4051 is overkill for this!

  • Awesome. Not sure what that means but I’ll start on trying to figure that out. *sigh. So I guess that means I’m ordering a couple of playground PCBs. Jesus. I can’t stop.

  • Hey CheeseNoOnions,

    wanna swap you SSM with a bunch of 4051s ;-) So you are building ot drom the Schematics? Coooool!

  • fcd72,

    Sweet! Ofcourse. I just need to desolder it with my 300W iron. I’ll put the gooey mess in an envelope and get it to you asap.

  • “First think, then solder else socket” – you soldered a SSM2300 directly to a board ;-) ??

  • No, I’m not building from schematics, but I have v0.5 boards so I was trying to see if I could figure out how to connect it. When I saw all the 4051s I remembered the datasheet for the SSM2300 said they were interchangeable which disappointed me a little but now I’m all kinds of excited. I have an extra cem3379 and an ssm2300, maybe I can make something on the playground PCB.

  • I was just kidding. I have it in one of those plastic covers that ICs come in, tucked away in it’s own drawer.

  • Ill take some pics tomorrow, so you can see where it connects. Its quite simple as the pads of the control boards 595 are easily accessible.

  • Wow, that's big cinema! it could be like my Q ;)

    I own a yellow Waldorf Q. I love its complete and clear "1 knob per parameter" UI. And yes - having 1 knob per parameter is a whole different! It expands the sound editing and live playing fun so much. The Q has also a very powerful modulation matrix and that's the only thing I really miss on the surface.

    @oootini: That was my first thought, too. But I think it could be cheap with a small PCB + some wires + pots. Like the Midi Box project expandable with small & inexpensive I/O boards. You get most out of your €/$/¥/...
    If I make Shruthi-1 big I think I would make it with all the pots & the 12(!?) matrix courts. Arp & Sequencer? I think for the Sequencer I work on the Midibox SEQ.

    I like the small Shruthi-1 acrylic case. I would build an optional programmer from the same material with a cable plug into Shruthi-1. The 4 pots are ok for continuos values but for switchable entries I would prefer stepping encoders.

    My Shruthi-1 runs since 5 days and I have to dive in its sound programming now. (The last nights are very short :)
    Then I decide what will be my next HW/SW project:
    - Midibox SEQ (running)
    - Shruthi programmer
    - Midibox SEQ 17x17 button - LED matrix (BLM)
    - Midibox SID
    - My own Shruthi-1 filter/FX board :)
    - Shruthi editor & patch library for OS X
    - My own (PIC or ...) Synth board. (I think of it for soooooo long. But now maybe it would be nice in a Shruthi-1 form factor to combine it with Shruthis filter boards!)
    - Waldorf Q editor & patch library for OS X
    - A mod matrix view and edit breakout for my Q!
    - ...

    That's enough todo for years! ;-)
  • Hey Wattsekunde, Start with the Editor + Patch Library and find someone who is willing to program a Web based Shruthi Patch Exchage Center – SPEC . Wouldnt it be cool to have a Program that shares your patches with all the others? As a reward I’d give you a kit for free.
    BTW if you like yellow, i can well make the Blacky Case for you in your Favourite Synth color (mine is Blue guess where that comes from….)

  • Here are the Pics that show how to connect the Programmer to “older” Shruthi Control Boards with a Revision Number lower than 0.6.

  • Thanks for the pics. Just so I’m clear, the wires you have attached to the IC are only because of the absence of the 0.6+ board additional ports, correct. For my boards (0.5), I’d have to solder the wires like you demonstrate in your pics.

    Are you going to offer the enclosure at all?

  • @ CheeseNoOnions

    Yes, logically are all boards the same, the changes were made to achieve a better placement of the parts in regard to lower noise on the digital lines and update the silkscreening. Otherwise they are the same.

    What color would you like for the enclosure? ;-)

  • Update:

    At the moment it looks like this: The Programmer will be a “small” kit, including PCB, ICs, Sockets, 4 LEDs (as i know you all like blinking lights, the male version auf the basic neuronal pattern that makes women force you to buy diamonds…), 32 PanelMount Pots, Connectors + the needed Wire. So no need to go outside and buy anything to make it work. As far as i can see it will be well under 90€.

    Also there will be a Kit with the Blacky Enclosure (this one also availabe seperately) + the Programmer Enclosure. I think there is no demand for a kit of knobs as everybody has its own opinion what the perfect knob will be.

    So now i need to know how many people are really interested to determine if i do the PCBs myself or produce factory ones and how much of every Part to order to determine the price.

    Everybod sincerely interested raise a Hand!

  • Hi,

    I’m very very interested.

    it’s good work

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