Any interest in a standard PCB layout for the frontpanel components?

[Doug Wellington]

Interesting to see this thread pop back up.  Everyone I've talked to about it really likes the MB-Seq, but none of them wants to build one unless there's a better control set up...

Now, I've thought about doing a modular sequencer, but after dealing with the MB-808, I'm a big fan of putting everything on as few boards as possible!  I started to design a sequencer with one board, but it seemed limiting, so I split my design in two - the 4x16 matrix and all buttons are on one panel, and the lcds, step leds and encoders are on a second panel, which I'm mounting into a separate box above the main panel.  Preliminary renders are at:

http://www.analognotes.com/mbmatrixseq

I've also been working on a wood case for the MB-808, so I think I'll try making one for this sequencer too...

Stay tuned,

Doug

[sonicwarrior]

I was thinking more of basic version (without the matrix or optional matrix) like

the original TK design.

I'm not sure if I like that splitted design. ???

[kokoon]

wow... i'm also from slovenia (like the guy mentioned in the first post)

i'd love to have a case and front made professionaly!

[nebula]

I've been working on a MB-SEQ  "backplane" PCB.  It has a CORE, 1-3 IIC MIDI modules, banksticks, and a bunch of DIN and DOUT.  It has sockets for some smaller boards to sit on top of it with banks of buttons and encoders.  The LCDs plug right into it too.  The aim is for a MIDIbox SEQ with very few, if any, wires between boards.  As an added benefit, the finished product should be pretty thin as a result of this.

I don't have plans to build an AOUT of any sort into the enclosure, although I will likely add the drum triggers on a DB25 jack.

My design isn't ready for prime time yet, but I could see how others might want to use my layout as a starting point, so I will be sharing.  The cool thing is that uses the least possible amount of space for two displays, the 16 encoders, and the trigger matrix, and you are then free to decide where to put the remaining buttons/LEDs and datawheel.

I expect to be etching this next week.  In the meantime I have temporarily diverted my attention to putting a MIDIbox CV together.  After all, a guy's gotta do something while the JB Weld cures... and his order from Smash is in the mail  ;D

[sonicwarrior]

Ok, so it seems there are currently 2 projects with some results and with different aims.

I'll definately want the AOUT options for my analog synths, but 2 projects seems already

enough and it would take at least a year for me to have something to show.

@nebula:

Do you already have a frontpanel layout or something to get an idea?

[brother303]

Hi all,

Nebulas ideas sounding very good to me,but for my personal needs I would prefer to have a cv/gate-option right on-board. Drum-triggers are also fine in addition to cv/gate outs...

The leds and buttons wich are not on the pcb can be easily put on breadboard or something,but a "basic-pcb" with most parts on it would be fantastic!

Even if a cv-option is not build in it seems to be easy to upgrade with a single aout/aout-lc or aout-ng board...

Greetz

Brother303

:)

[nebula]

Your points are taken... there is likely room for an AOUT. The big board is smaller than the panel will next to be.  All the brains fit behind the displays and under the button matrix, so there will still be space underneath the remaining buttons - an AOUT could easily be put there.  This isn't rocket science, it's just moving some components around!

@Sonicwarrior: all my designs so far are on paper, except my halfway done PCB layouts (which are in AppleWorks drawing). My PCB creation methods are primitive (but effective). I'll see if I can show you a sketch by tonight.

[sonicwarrior]

Thanks.

If you'll include the AOUT option I'm definately interested if the resulting design is not too bad.  ;)

[brother303]

Hi folks,

any news here? Did Nebula send his files to you,Sonic?

Greetz

Brother303

:)

[sonicwarrior]

No, I didn't got any files. I thought nebula would show some pics here.  ???

[brother303]

NEEEEEEEBUUULAAAAAAA, ;D ;D ;D ;D

...can U hear us?

;)

[nebula]

OK ... I have made some progress since I last posted here, but my work so far isn't ready to be looked at.  I'm getting much closer, so let me explain where I am right now:

- I am considering NOT laying out the components for a full CORE on the backplane, because I'm only designing a single-sided board, and Smash's CORE module puts all the headers right where I want them without having a routing nightmare. So I think the backplane board may incorporate some SIL/DIL headers to that Smash's CORE can sit on top of like a daughterboard.  I haven't gotten around to laying out the CORE components yet, so don't quote me on that - it's just a consideration.

- The IIC MIDI modules, power rectification/regulation/filtering (including a second 5V regulator dedicated to both display backlights), and all of the DOUT is on the backplane. 

- The backplane has headers for 2 primary daughterboards, each with 8 encoders and 8x4 tactile switches. It would be possible to redesign the daughterboard to include the LEDs for the matrix, but I have decided to only put the switches on the daughterboard while the LEDs will be soldered to the backplane.  My button/encoder daughterboards will have holes drilled in them for the LEDs to poke through.  This is due to my thick panel material being too close to the daughterboard PCB when mounted, leaving not enough room for LEDs.  Still, the backplane is designed with additional headers, so if you wanted to put LEDs on the daughterboards you could (I'd recommend SMT LEDs or illuminated switches for this purpose though).  The DOUTs required for this are on the backplane, while the DINs are on the daughterboards.  When you see this it will make sense.  Each of these daughterboards is measured to precisely line up its control columns with the Optrex 40x2 LCDs recently bulk-ordered.  (And I have more - PM me if you're interested)

- All jacks are mounted to the top of the backplane, to appear at the back panel of the enclosure.  LCD brightness and contrast pots also make an appearance here. 

- There are then headers for the V3 track group, track select, layer and trigger layer buttons on the left, and the remaining general buttons in another 4x8 matrix layout on the right.  The left board hovers above the backplane and uses the same LED method as the matrix board.  For the buttons on the right, the same "LEDs on the board behind the button board" scheme applies.  The LEDs are driven from DOUTs on the main backplane, but the buttons have dedicated DINs.  A very short ribbon cable or two will be required for this.

The main reason why the backplane doesn't go all the way to the right is that I don't have a piece of copper-clad PCB material big enough.  But others who decide to use my design also gain the advantage that they can put the general-purpose and transport buttons wherever they like.

- There will be space to mount an AOUT, AOUT_LC or AOUT_NG board behind the left display.  You will need to run leads from the module to a header at the CORE, and run the outputs to one of two general-purpose PCB-mounted DB25.  I haven't considered AOUT's power supply requirements yet, but I will.

- I'm in the middle of relocating DIN circuitry from the backplane to the daughterboards, where I now believe they should go.  This cleans things up a lot.

- This layout is ideally suited for those interested in etching their own circuit boards.  Everything is single-sided and there are no traces that need to run between pins and the like.  If I was planning to have boards fabricated I'd be using a real PCB design package and I would run micro-thin traces.

I haven't shown my work yet because it needs clean-up.  There are a couple of very obvious oversights and errors I have made that I want to resolve before I show my work-in-progress.  Sadly, I won't get to working on it again until Wednesday night. The fact that people are interested is motivation for me though!

In my experience, when you create something like this, you work from the exterior to the interior, otherwise you end up compromising your device's form factor to accomodate your electronics.  As it is, this is shaping up to have a panel about 7" x 24", including LED tempo display, 4x16 trigger matrix and all internal electronics in a device that will be exactly 1 inch thick (back panel to front panel - protruding knobs and buttons don't count).

[brother303]

Hi Nebula,

lots of information,thank you. Have to read this closely once again... ;)

One idea : Since it isn`t planned to put everything on one single

pcb,wouldn`t it be cool to divide the pcbs into "control-surface" and "base"-pcb,similar to the mb6582?

Greetz

Brother303

[Echopraxia]

this is shaping up to have a panel about 7" x 24", including LED tempo display, 4x16 trigger matrix and all internal electronics in a device that will be exactly 1 inch thick (back panel to front panel - protruding knobs and buttons don't count).

That sounds awsome! I know your super busy with this so I will leave you alone for now ::) but I did have one question about the size of the board. Would it be impossible to get everything into 19" rack size. I personnaly don't care but I would think that it would be a good option. Anythoughts?

Also are you saying that this pcb will have have everything (douts,dins,iics,8 banksticks) on the backside and all of the encoders and buttons on the front side????

[nILS]

NEEEEEEEBUUULAAAAAAA, ;D

RIIIICOOOOOLAAAAAAAAAAAAA!

[nebula]

Hi Nebula,

lots of information,thank you. Have to read this closely once again... ;)

One idea : Since it isn`t planned to put everything on one single

pcb,wouldn`t it be cool to divide the pcbs into "control-surface" and "base"-pcb,similar to the mb6582?

Greetz

Brother303

No real advantage to that IMHO.  Different people design differently - I am from the school of thought that DINs belong on control surface PCBs.  It drastically reduces the amount of interconnect between the boards.

[bugfight]

... I am from the school of thought that DINs belong on control surface PCBs.  It drastically reduces the amount of interconnect between the boards.

exactamundo...

spaghetti is good, but not for wiring.

[nebula]

I know your super busy with this so I will leave you alone for now ::)

I am unfortunately NOT super busy with this.  I am super busy with other stuff in my life right now, including holidays coming up, and I wish I had more time to spend on this :(

but I did have one question about the size of the board. Would it be impossible to get everything into 19" rack size.

The backplane board would fit into a rack enclosure without modification, but if you wanted to do that you'd just need a longer ribbon for the board with all the action/general purpose buttons, and figure out a place to put it.

Also are you saying that this pcb will have have everything (douts,dins,iics,8 banksticks) on the backside and all of the encoders and buttons on the front side????

No...  There is a big PCB with CORE, IIC modules, power, jacks, banksticks and DOUTS.  It has header sockets for two 40x2 LCD (so no ribbon required, just some long pins).  It has header sockets for front panel boards to be screwed right down on top of it, just like the LCDs.  The front panel boards (which have encoders and buttons) have their own DIN IC's.

Just so y'all know ... this most certainly will not be for everyone, although it's probably a great starting point for certain people - like those interested in etching their own boards, and those interested in a highly integrated, compact SEQ.  I would be flattered if my design ends up being a springboard for somebody working on their own SEQ, so I will happily accept suggestions (i.e. making it possible to fit an AOUT into this whole mess), but I strongly encourage you to not wait for my work.  It may take longer than expected, I keep making changes, and it may not be what you want.

[Echopraxia]

I know your making the 4x16 button matrix.Have you decided on what size tact switches to go with? I have used 12mm x 12mm and have found them to be very nice size for standard seq layout (not 4x16) The 12mm switches also have a much longer life span than 6mm from what I've read.

[nebula]

I'm using the same switches as MB-6582, but changing the footprint would be a snap.  My design uses a plexiglass panel and homemade enclosure.

[Wilba]

No real advantage to that IMHO.  Different people design differently - I am from the school of thought that DINs belong on control surface PCBs.  It drastically reduces the amount of interconnect between the boards.

I agree... don't use MB-6582 as a reference design, it is only by pure luck (and countless hours of rearranging tracks) that I was able to fit it onto two boards that would fit in a PT-10 case. If a control surface is not as compact as MB-6582 then it makes much more sense to put the DIN and DOUT modules on the same PCB as the control surface components.

Then again, I'm probably going to repeat the same mistakes and aim for a 14" wide MB-SEQ control surface PCB and probably have to put the DIN and DOUT on a second PCB.  ;D

[bugfight]

...

Then again, I'm probably going to repeat the same mistakes and aim for a 14" wide MB-SEQ control surface PCB and probably have to put the DIN and DOUT on a second PCB.  ;D

if space is tight, use smd serial registers.  the SOIC chips are not so hard to solder...

plus if you keep the registers close to the controls they support, you need less space for running traces across the pcb.