TK.

MIDIbox CV V2 Concept

307 posts in this topic

Cool!

 

Only complain: please replace "MIDIBOX" by "MIDIbox"

 

I guess that such a generic CS could also be interesting for MIDIbox NG users.

Therefore it makes sense to layout a frontpanel PCB for the upper part above the encoders (once enough people are satisfied with the available control elements of course).

 

Best Regards, Thorsten.

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Note: The control surface encoder could also have a button which could be used for a "fast" mode.



Updated:

 

midibox-cv-v2-CS-02a.jpg



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.

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For a cheap case I would suggest to make sure that all necessary parts fit on a Ponoko/Formulor P2 format, i.e. 384x384mm. With sneakthief's design this seems to be just about possible, although the total inside height will only be about 31mm - very tight, I guess. Every mm you save in terms of width can be added to the height...

 

Can you explain this to me a little bit more? I was on the Ponoko website and just got lost :P

 

The largest size possible is 31.1 inches by 15.1 inches (790mm x 384mm).

 

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:

 

midibox-cv-v2-CS-02b.jpg

Edited by sneakthief

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Yes, looking very good, sneakthief! :smile:

 

Many greets,

Peter

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The centered CLCD looks even better! :)

But I'm right-handed, and therefore would like to see the main encoder at the right side of the CLCD.

 

In order to get the CLCD still centered, you could move the OLEDs to the left upper corner (the appr. buttons won't be used so often), and the 3x3 button array to the right upper corner (I guess that these buttons will be used very often).

 

Best Regards, Thorsten.

 

P.S.: we could design an alternative PCB for left-handed people! ;-)

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midibox-cv-v2-CS-02b.jpg

 

I actually like this design very much, and also agree completely with TK's remarks; menu encoder on the right, GLCDs on the left.

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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.

 

midibox-cv-v2-CS-04a.jpg

 

 

midibox-cv-v2-CS-04b.jpg

 

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

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Wow this looks perfect, nice work gang! I would vote for a Ponoko type case, ala Sammich devices. If there's a gorup buy for this, I'm in. I'm sure most people who have the Encoder / LED boards would buy into this.....

Maybe the top 3 elements (buttons, LCD, OLEDs) could be split into separate PCBs, then you can order your front panel depending on your preference i.e. left handed or right? Modular designs are always more felxible.

In terms of height of the box, will this attempt to include the AOUT in the same box? I would suggest not. My plan is to put the AOUT behind a panel in my synth, and drive it with the core / front panel controls over a transistor buffer. That means the AOUT can be close to the dual power supply in the modular, and the control panel can be mounted close to the iPad away from all the modular's cables ;)

What would be amazing would be to use this proposed surface as a generic surface to also edit my other devices, MBFM and MBSIDs, all from a central panel :D

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In terms of height of the box, will this attempt to include the AOUT in the same box? I would suggest not. My plan is to put the AOUT behind a panel in my synth, and drive it with the core / front panel controls over a transistor buffer. That means the AOUT can be close to the dual power supply in the modular, and the control panel can be mounted close to the iPad away from all the modular's cables ;)

 

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.

Edited by sneakthief

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Since Sneakthief made it easy for lazy folks like me, i just modified the .psd a little.

Some thoughts:

 

-symmetry makes it southpaw-friendly

-could easily be scaled to builders needs

-only one type of display->lpc17 will suffice

-could be used as 1 OLED, 2 buttons, 2 encoders per CV channel

-could be built without LED-rings, OLEDs could show values


gallery_5257_63_441888.jpg

Edited by Imp
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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

Edited by sneakthief

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I like Sneakthief's layout as it is.

And I like Monokinetic's idea to split the upper elements into 3 parts (which will require 3 PCBs), so that builders can decide by themself, where to position them, and if they need them at all.

 

E.g. if somebody doesn't want to spend the money for the OLEDs, he could replace this element by another GP button array (e.g. 5x3) at the left side.

Or by a 4x2 pot array

 

The SCS (CLCD + 6 buttons + rotary encoders) ensures compatibility to most other MIOS32 based MIDIbox projects, which becomes interesting once you want to try out a new application before planning a special case.

 

 

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

 

For the MBSEQ project I defined the pin assignments for a 25pin sub-d: http://www.ucapps.de/midibox_seq/mbseq_v4_interconnections_lpc17.pdf

 

The advantage: it can also break-out the SRIO chain, e.g. for the 64 additional gates (which btw. could also be made available for MBCV2, e.g. if somebody would like to trigger drum sounds).

 

But the breakout cable has to be very short!

I noticed instable CV values (or no function at all) with a cable which was longer than 50 cm.

 

Longer distances could be achieved with differential line drivers, e.g. according to the RS-422 standard.

Here an app note which describes this well: http://www.ti.com/lit/an/slyt441/slyt441.pdf

 

Trying this out is still on my TODO list.

Here are some suitable chips which are available at Reichelt:

4-line differential driver http://www.reichelt.de/ICs-M-MN/MC-3487-DIL/3/index.html?&ACTION=3&LA=446&ARTICLE=11346&GROUPID=5474&artnr=MC+3487+DIL&SEARCH=differential+driver

4-line differential receiver http://www.reichelt.de/ICs-M-MN/MC-3486-DIL/3/index.html?&ACTION=3&LA=446&ARTICLE=11345&GROUPID=5474&artnr=MC+3486+DIL&SEARCH=differential+receiver

 

If I've success with this approach, I will change the 25-pin sub-d pinning accordingly (there are enough free & redundant pins available)

 

Best Regards, Thorsten.

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Speaking strictly from a selfish point of view: I built up my MBCV2 with a 128x64 DOG GLCD and an SCS-style panel. I did this because the GLCD fits well in a 2U-wide panel for my 5U-format modular synth, because I wanted to play with one of these LCDs, and because I plan to mostly use the Lemur interface. Hence it would be very useful to me if it were possible for MBCV2 software to use just one GLCD to display both the SCS interface and an oscilloscope. Obviously it would be necessary to somehow switch between these two modes--unless TK wants to be really clever and put the SCS text fields and the oscilloscope on one GLCD. :hyper:

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No problem, I planned to display the first scope at the first GLCD anyhow, and if only one GLCD is configured, the SCS will appear at the two lower lines.

 

Best Regards, Thorsten.

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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:

 

DT_6_SW.jpg

http://www.reichelt.de/Eingabetaster-Digitast-/DT-6-SW/3/index.html?&ACTION=3&LA=2&ARTICLE=7241&GROUPID=3280&artnr=DT+6+SW

Edited by sneakthief

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2. Can I buy an LED encoder ring PCB from someone to try to make the case prototype?

 

If there is nobody else with a spare board, I will send you one of my boards which is already stuffed (I've 5 LRE8x2)

 

 

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:

 

+1 for these buttons, I like them more than the buttons that we are using for Wilba's MBSEQ Frontpanel.

/Edit: unfortunately the cap height doesn't fit with the LCDs!

 

Important: they need 9.5mm in diameter (I checked this with the .fpd files of my MBSEQ V2 and MBFM frontpanel)

Otherwise it will be too difficult to fit them into the holes if they are not 100% accurately soldered (which is the normal case...)

 

Best Regards, Thorsten.

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Some progress: I mounted the frontpanel components on veroboard to check dimensions, the surface feel, and of course to prepare the firmware.

 

First issue that I noticed: unfortunately the ITT Shadow buttons are not the perfect choice, since the button cap height doesn't fit with the LCDs (considered, that a 3mm acryl panel will be on top of the LCD/OLEDs):

mbcv_proto_button_issue.jpg

 

Therefore we've to decide for other buttons (I'm using mini buttons for the prototype just to keep it cheap)

 

On the picture above, you will also notice the second issue: between each OLED there has to be a 100 mil gap, otherwise they won't fit side by side.

 

Next picture shows OLED and SCS PCB together:

mbcv_proto_lcds_aligned.jpg

 

OLEDs and CLCD are aligned! This is the most important message! :smile:

 

But: due to the wider OLED part of the panel, the CLCD won't be centered anymore:

mbcv_proto_with_lre8x2.jpg

 

Therefore the big question: does it make sense to move the SCS to the right side?

mbcv_proto_with_lre8x2_alt.jpg

 

Advantage: this could speed up the menu handling.

E.g. choose a menu page with the left hand, while tweaking parameters with the right hand!

 

 

Some additional words to the button array PCB: I'm using 3x4 buttons now, there will be enough DIN inputs free

 

 

Some words to the OLEDs:

in order to use them in parallel to a CLCD, they can't be connected to J15 anymore. Not only because of the different interface, but also because they have to be supplied at 3.3V, but the CLCD has to be supplied at 5V

 

I spent some thoughts about this IO conflict, and finally came to following conclusion:

1) OLEDs will be connected to J5A and J28

2) the gates will only be available at DOUT shift registers, and not at J5/J28 anymore

 

This might sound like a big drawback (additional hardware required for the gates) -> wrong!

Because gate outputs have to be buffered and protected with 220 Ohm resistors anyhow, see also this circuit from MBSEQ: http://www.ucapps.de/mbhp/mbhp_core_lpc17_output_buffers.pdf

 

So: instead of taking a 74HCT541 for buffering parallel outputs, a 74HC595 can be used for exactly the same purpose with the only difference, that it's loaded from a serial chain -> J8/J9

 

Therefore I think that this will be an acceptable solution.

It also prevents, that somebody is trying to connect his synths directly to J5/J28 without protection, e.g. because he missed to read an important detail in the documentation, or just isn't aware about the dangers.

 

Best Regards, Thorsten.

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TK, here's another pushbutton option that is similar to the ones you were using. They are two piece and roughly the same price. The cap has a slightly smaller diameter but they are taller. The footprint looks to be the same and the behind the panel is the same. They are made by the same manufacturer as well. 
 

http://www.digikey.com/product-detail/en/KS-03Q-01/EG4794-ND/2116273

http://www.digikey.com/product-detail/en/ACC-C17-2/EG4804-ND/2116283

 

 

Some progress: I mounted the frontpanel components on veroboard to check dimensions, the surface feel, and of course to prepare the firmware.

 

First issue that I noticed: unfortunately the ITT Shadow buttons are not the perfect choice, since the button cap height doesn't fit with the LCDs (considered, that a 3mm acryl panel will be on top of the LCD/OLEDs):

Edited by gpmacklin

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Thanks for the hint! I like the shape of this button, but Digikey is no option for me :-/

We should open a separate button decision thread, because the choice will affect many projects which get use of the SCS (Standard Control Surface with CLCD, encoder and 6 buttons)

 

Background: In Germany we usually prefer to purchase components from Reichelt. Prices are cheap and delivery is superfast. Therefore I've preferences which might look strange to you US guys. On the other hand, Mouser enhanced their business in Europe, so that it's much easier to order parts from this distributor. This has to be considered. I tend to propose Mouser as the preferred supplier in future... but this is another topic ;)

 

News from the frontpanel side: the experiment to control OLEDs from J5 & J28 pins in parallel to a CLCD connected to J15 was successful:

mbcv_proto_parallel_lcd_output.jpg

 

Next step: a proper integration into MIOS32 to make the GLCD type configurable and not application dependent (this will be a challenge!), because I'm sure that MIDIbox NG users will be interested on this option as well!

 

Best Regards, Thorsten.

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Crazy!!!
That looks fantastic. There is nearly no progress in two years and then this!!!! Incredible job from all of you. 
I really like the CS design. Well done...
Here are my thoughts.
- My experiences with the lemur control surface where similar to Thorsten. It is nice but not intuitive enough. And in the end it distracts you from tweaking. 
- the main fun for me is the physical separation from iPad and midibox cv (wifi router).
- the second main fun with lemur are the bouncing balls, the x/y pad (I did implement them in the lemur program), the motion sensor (i wanted to implement but got distracted), and of course the graphical envelope/Lfo. Drawing on the iPad is fun, turning knobs not. 
- one thing I don't like with the lemur and I think it is implemented that way. When changing cv channels the display is not updating. 
 
But I'm sure that people would also like to have dedicated buttons for
- a "fast" button (for the encoders)
- encoder bank +/- (for the case that they don't have inbuilt switches)
- patch +/- buttons
- Start/Stop sequencer (and arpeggiator)
- store button to save the current patch
- change directly to certain menu pages
 

- definitely buttons for the 8 cv channels. 

- standard scenario for me: do the setup and all the routings (Lfo -> envelope etc..) and save it. then play around with levels of the various function generators. 
- so the lemur is good for setup and as a performing tool with the motion sensor and the big X/Y pad. 
- the CS Box is good for tweaking and fine control of the levels. And we have visual feedback of the outputs via the graphical displays. The Aout needs to be close or inbuilt to the CS. 
- Does anybody know of a small wifi - router to be build in the CS Box? 
- CV in and Gate/Pulse in would be a nice enhancement. To sync lfo´s or trigger Envelopes from extern. CV in could be used to quantize voltages... I need to test this with an cv to midi interface...
- And the last: Patch Morph? 
 
Might these thoughts be helpful for someone. 
Christoph. 

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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?

 

midibox-cv-v2-CS-05.jpg

 

 

The Aout needs to be close or inbuilt to the CS. 

 

 

 

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.

Edited by sneakthief

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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:

 

midibox-cv-v2-CS-05b.jpg

Edited by sneakthief

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...

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.

 

I'll chime in here since I've designed quite a few plexi cases at this stage:

 

1: Decide on a clearance between the case and boards and work around that. 11mm is what I start at, most parts will clear 14mm easily and it gives you a bit more breathing room for displays

 

2: Decide if you want windows for displays.  I personally dont like the displays exposed and always put a window in front.  This also means that you need a fair amount of space between the panel and PCB, a cutout, or a thin display.  In this case, going to a 20x2 OLED seems to make the most sense to match the little ones..

 

3: Case colors: Personally, I dont like the clear/tint plexi since it just gets covered in finger prints instantly.  The matte black is my go to but you really have to fill in the engraving which can be tricky.  There are a couple of threads about the techniques people use to do it.  

 

4: with matte black, dealing with the LED rings can be done in two different ways imo: cut holes for all the LEDs and just stick them through the top panel or you can just make a clear round piece that snaps in like a display window with a hole in the middle for the encoder shaft (or a u shaped on for that matter, keep the middle black)

 

100% agree on the CV/gate jacks not being on the "brain", a D connector to a breakout box is the way to do it even if it's only a foot of cable connecting the two.

 

One other thing I dont think anyone has touched upon is the real estate that the core, aout, and any other related boards will take up behind the CS.  

Edited by Altitude

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@Chriss: thanks for the valuable input! I'm planning to setup a new webpage for the project which summarizes the facts and wishes, so that we know where we are :smile:

 

 

- one thing I don't like with the lemur and I think it is implemented that way. When changing cv channels the display is not updating. 

 

it should update automatically on CV channel changes.

Are you using the MIDI or OSC option?

Could you please try the latest .jzml file in the SVN repository? I adapted it to the latest Lemur version, the old one wasn't 100% compatible.

 

 

- Does anybody know of a small wifi - router to be build in the CS Box? 

 

There are several mini-router available at Reichelt for around 25..30 EUR

To people who want to use the (preferred) MBHP_CORE_STM32F4: it won't provide an ethernet port anymore.

 

@Sneakthief

 

- The OLED/CLCD pcb layer looks to be about 15mm high, right?

 

Yes, correct, it's ca. 15 mm measured from PCB bottom to OLED top

 

- My guess is that the MIDIbox LPC/STM32F4 is 22mm including the solder protrusions on the bottom. Can somebody verify this?

 

I would calculate 30 mm

 

For STM32F4 I can't confirm yet, but it will be ca. 30 mm as well

Here btw. a preview of the PCBs - they have a different format compared to MBHP_CORE_LPC17!

 

MBHP_CORE_STM32F4: 120x88 mm

mbhp_core_stm32f4_v0.png

 

 

MBHP_MIDI_IO: 103x44 mm

mbhp_midi_io_v0_rotated.png

(two MBHP_MIDI_IO boards can be chained for 4 MIDI INs and 4 MIDI OUTs)

 

Best Regards, Thorsten.

 



TK: What's the height or your CLCD and where did you buy it? I don't recognize it from Reichelt, Conrad or Pollin.

 

I bought it from Ebay for 5 EUR

But the height is very similar to all 2x20 CLCDs that I know. You can calculate the same height like for the OLEDs

 

 

Also, the middle buttons should be moved over to the right as much as possible so the OLED's can go further right:

 

Of course, no problem for me if you adjust the alignments. 

 

Best Regards, Thorsten.

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