sneakthief

Are those mono potentiometers instead of stereo ones? That could explain it - because it looks like SIDs 1 and 2 are connected together at the pot and being summed to both left and right.

As mburch suggests, you'll definitely be happier with smaller knobs. Maybe if you do another DIY project, you can buy smaller knobs for this one and re-use the ones here for your future ones.

- I ended up ordering these yellow/blue OLEDs from yoybuy as TK suggested: http://www.yoybuy.com/en/Show/20416112533 - For the CLCD, I wanted something to match the OLED so I chose this one: http://www.ebay.com/itm/Black-20x2-Character-LCD-Module-Display-w-HD44780-Controller-Bezel-White-Backlit-/291020230914?pt=LH_DefaultDomain_0&hash=item43c2285102 It really seems like there's no real standard for CLCD dimensions. They range in height from 12.5 - 15mm and the position of the actual LCD window can vary by several mm. Any case will have to take these variations into consideration unless you force people to buy one single model. Either that, or you simply make the window above the CLCD several mm larger.

I wonder how noisy these DC buck/boost dual +/- converters are? Because it would sure be handy to get +/-12V from a simple 5v supply. http://www.ebay.com/itm/DC-Boost-Step-Up-Voltage-Converter-Positive-Negative-Dual-output-3-6V-to-5-32V-/350950442534?pt=LH_DefaultDomain_0&hash=item51b646c626

Marxon - the prototype boards are being tested soon: Check out this thread to see what will also end up being the control surface for the MIDIbox CV platform:

Acul:

Re. 2. The 128x64 OLED's are also 13.5mm high, so there's no point getting a thin OLED 20x2. Not to mention, 20x2 OLED's with parallel interfaces are rare and expensive. AFAIK there's Newhaven and Crystalfonts: http://de.mouser.com/ProductDetail/Newhaven-Display/NHD-0220DZW-AY5/?qs=sGAEpiMZZMshRHSPqbouvApOhG8IakcvZgXzNLCZ5HI%3d http://www.crystalfontz.com/product/CFAL2002AY As for me, I'm not going to touch another Crystalfontz OLED after having 5 slowly die on me. Crystalfontz wouldn't even offer to replace them for me, even though they obviously had many defective ones, eg. the Sequentix P3 had to have many of their Crystalfontz OLED's replaced. Re. 4. It may actually be cheaper and better looking to cut and engrave a thin, black, matte plastic overlay on top of a clear acrylic case. In one step you solve the problem of text engraving, windows, 256 LED-ring holes (or clear C-shaped inserts) Re. 5. At this point, it looks like a P2-sized plexiglass (384x384mm) is simply too small. I think it makes more sense to stick the AOUT board in the breakout box, like TK does - or even better, behind a Eurorack panel that can supply it +/-12V. One less PSU to worry about!

TK: What's the height or your CLCD and where did you buy it? I don't recognize it from Reichelt, Conrad or Pollin. Also, the middle buttons should be moved over to the right as much as possible so the OLED's can go further right:

First of all, the 2nd layout with the CLCD on the right seems ergonomic to me. 1. I'm not sure if we can fit everything within a Ponoko P2-sized case (384x384mm acrylic piece cut into a box). Let's consider the top panel: - The LED ring pcb is 342mm wide and it would need at least an extra mm of room, hence the width of 343mm that I chose. - The top panel needs to extend 3mm on each edge to overlap the side pieces, meaning a width of 349mm - That leaves 35mm of vertical height inside: 384mm minus 349mm (Imagine that the single 384x384mm "P2" acrylic piece gets cut into 4 pieces - top panel next to one side panel, bottom panel next to a side panel, then the front panel, then the back panel) - The OLED/CLCD pcb layer looks to be about 15mm high, right? - My guess is that the MIDIbox LPC/STM32F4 is 22mm including the solder protrusions on the bottom. Can somebody verify this? So that's a total of 37mm for both pcb layers... 2mm too much, not including space needed between the boards. 2. Re. case style: Some of the options I was personally considering for an acrylic case... - A clear acrylic case with a nice scratch-resistant laser-cut overlay. This way the LED-rings, OLED's and CLCD don't need to have holes cut out and have a protective layer. Downside: a few extra $ for the overlay. - Transparent gray acrylic. Looks nice, hides the ugly pcb's underneath. Downside: I find smooth acrylic cases scratch too easily and collect dust like crazy :( - Matte gray acrylic. Same as above, less prone to scratches. Downside: Will the LED-rings be visible enough? Will any engraved text be legible? I don't think building it into the CS box makes any sense. You simply don't want up to 16 CV/gates from a desktop unit extending all the way to your modular. Please trust me on this. I've been building my DIY-modular for 10 years now and as your modular grows (which it inevitably does!), you'll see what I mean.

1. Anybody with experience making Ponoko cases want to take this layout into Inkscape? I really don't know best practices for connecting the case sides and everything else. 2. Can I buy an LED encoder ring PCB from someone to try to make the case prototype? 3. I made the holes 10mm in diameter but I think they should be 7mm for these affordable but decent quality ITT Schadow switches that TK uses: http://www.reichelt.de/Eingabetaster-Digitast-/DT-6-SW/3/index.html?&ACTION=3&LA=2&ARTICLE=7241&GROUPID=3280&artnr=DT+6+SW

Imp: I don't think you realize how tiny those display are - the viewing area is 21.74 x 11.20mm. Try cutting out a piece of paper that size and you'll see what I mean. I have a little XMega Protolab mini oscilloscope ( http://www.gabotronics.com/development-boards/xmega-xprotolab.htm ) which uses a similar display. It's good for waveforms but when it comes to going through parameter settings, the 20x2 CLCD is a much better solution. I would recommend going to a larger GLCD if you really want to go this route. Don't forget, somebody would have to rewrite the user interface to compensate for the lack of the SCS (standard control surface): 1 encoder, 2 dedicated buttons and 4 soft-buttons. Not to mention, the STM32F4 setup is more affordable ...assuming the MIDIbox carrier boards are the same price: 16e 1x STM32F4 27e 4x SSD1306 OLEDs 8e 1x 20x2 CLCD Total: 51e 28e 1x STM32F4 54e 8x SSD1306 OLEDs Total: 82e

I'm assuming most people would prefer to have the jacks in an accessible place, meaning you could mount the CV/gate jacks in a Eurorack panel and power it with a modular's +/-12V. Or in a little box like TK does. What about using a 15-pin VGA D-SUB connector between the CS and the outputs? It has 15 pins plus shield: - 8 pins for gate - 1 pin for clock - 1 pin for start/stop - 5 pins for AOUT (Vs, Vd, CS, S1, SC) - 1 pin for the shielding ground Someone would of course have to test this first to make sure there isn't too much interference from the digital signals. Maybe a 1m cable VGA would suffice? To conclude, the Eurorack panel would have a 15-pin VGA D-SUB connector, 8 CV out jacks, 8 gate out jacks, 1 clock jack, 1 start-stop jack. You could optionally add 8 buffered LED's for the gates.

I took the time to space the buttons evenly and to center the CLCD. Having the CLCD centered seems more important than having the OLEDs come further over to the right. PSD: http://sneak-thief.com/midibox-cv-v2-CS-04aaa.psd PLEASE NOTE: I decided to use the dimensions of the Alientek OLED that TK suggested. It seems OLED1306's come in various pcb sizes with different pin header placements. http://item.taobao.com/item.htm?id=6239945991

Can you explain this to me a little bit more? I was on the Ponoko website and just got lost :P OK, I shrank everything width-wise as much as I could based on the LED ring encoder board. Watching TK's video, I liked seeing the cv/gate info alongside the LFO's so I moved the screens together. Is there anything I can do better? This is what the internal PCB spacing is like:

Note: The control surface encoder could also have a button which could be used for a "fast" mode. Updated: This is really fast and sloppy... the top button-spacing needs to be tweaked for consistency, not to mention to accommodate any text-labels that may be required.

(see my later post with the updated layout)

Here's the quick and dirty Photoshop PSD if anybody else wants to have a crack at it (150dpi): http://sneak-thief.com/midibox-cv-v2-CS.psd

That ring encoder board is huge - 342 x 85.5mm If you want to use it, here's what I propose. I left the circuit boards for the ring board, LCD and OLEDs partly visible to give an idea of why everything is layed out this way. It's got the minimum standard control surface (SCS), 2 extra buttons for whatever and a button to select each of the OLEDs: I used this $10 USD 20x2 LCD as a reference: http://www.ebay.com/itm/Character-LCD-Module-Display-Screen-LCM-20X2-2002-20-2-Compatible-HD44780-/200659773145?pt=LH_DefaultDomain_0&hash=item2eb84126d9 And this SSD1306 OLED for $8.86 USD: http://www.ebay.com/itm/SPI-IIC-0-96-128X64-Yellow-Blue-GreenLand-OLED-Display-Module-SSD1306-Arduino-/200961405051?pt=LH_DefaultDomain_0&hash=item2eca3bb07b TK: I don't know if you wanted to use encoders with switches... there could be a lot of dedicated buttons for specific modes, thus eliminating menu-diving! Also, I didn't see any cases large enough for that ring encoder board. Anybody have any suggestions?

Would the CS be a replacement for the Lemur? FWIW, you can get a used iPad 1 for about 40-50 euro on eBay here in Germany. For around 100e including the Lemur software, it's hard for a physical interface to compete when it comes to getting the "bang for your buck". If it's complimentary to the Lemur, then what you want on a physical CS is a whole different story.

Are there any big hurdles for getting this to work on the STM32F4 discovery?

Thanks Kanji! That's true synth-DIY spirit :)

Hey Kanji - do you have a document which lists the DOUT and DIN connections? That would be amazingly helpful for people trying to recreate what you've done here!

Ohhh, I should have spent more time reading the datasheet!

Is this info that you posted on the new STM32F4 page still true? I was under the impression that one DAC was freed up and all the pins for a high-speed SDIO SD card were now enabled? Or am I totally confused?

Nice work on finding out how to relocate the SD CS pin to PB2 to finally free up the DAC! (Right?)