Basic specs - does this make sense?

5 posts in this topic

Okay. I'm pretty sure I've got my head around how this should work.

This is my first, and probably only, MBHP SEQ build. I've got a handful of basic boards on hand, and a couple of almost-complete parts orders (recently moved, so I had to throw all of my resources at that). This is going to be my winter project. Initially, I was thinking of doing something more custom as far as a layout goes, doing crazy stuff like a harmonic keyboard and such, but now I've scaled it back a bit and am focusing on function over form.

Using WIlba's frontpanel as the control surface. I've got a fair amount of MIDI gear I'll want to control, so I'm going for the maximum MIDI ports I can - from what I can tell, that's a total of 12 outs, and 4 ins. There's also some custom DIY synths that I'd like to control, so 8x CV outs and 8x Gates would also be nice. I'm also looking to do weird clock division stuff with some Korg Volcas (total of 8) and to use the BLM16x16+X as an extended control surface later on.

So here's what I'm thinking will be required for modules:

  • CORE_STM32F4 running MIOS32. 
  • WIlba's Frontpanel taking up the first modules on the DOUT/DIN chains (J8 and J9, respectively)
  • Four additional DOUT modules after the frontpanel on J8 for an additional 16 SRs - 8 for analog synth gates, 8 for the clocks to the Volcas
  • A single AOUT module on J19 for CV outputs
  • 2x MIDI_IO Modules on J11E for a total of 4 INs and 4 OUTs.
  • 2x Quad MIDI_IIC modules chained on J4A for 8 dedicated MIDI outs (bringing the total to 4 IN and 12 OUT)
  • Two LCD displays on J15A/B
  • TPD Module on J1

Does this all make sense and fit within the specs of the platform? 

I'm so pumped to get this together...

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Welcome Mr Hubbard. I'm not going to comment on whether that all fits within specs, someone more knowledgeable can do that. It kinda looks ok me. Nice to see you're pumped but I will say the usual disclaimer. Midibox building is a journey, it takes time and patience but is very satisfying. There's lots of hints and tips on the forum (check the build threads in Hints and Tips) to get you round all the little intracicies you'll encounter during the build as part choices come and go and forum posts stay frozen in time. Here's some tips;


  • Read everything you can in recent build threads
  • Research part choices carefully. One forum post may sing the praises of something then 2 months later there's a gotcha. (e.g. Encoder choices, buttons etc)
  • Beware of feature creep. Some tiny little mod later in your design can have huge impacts and set you back weeks.
  • Cases are expensive. This can easily be 50% of your time.
  • Oled's are great but expensive and don't like heat (talking from experience).
  • Muse on Plancks length and solve problems quicker than Watson[IBM] while soldering.

Have fun!

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Sounds good!

Minimal comments:

* you probably only need a single DOUTx4 board for 16 digital outputs.
* best to put the TPD at the end of the SRIO chain, as it has an uneven amount of shift registers.
* you might need to change the firmware for 8 IIC MIDI ports (imho only 4 supported in the standard firmware, allowing an already plenty 4+4 out ports)
* start with the smallest possible setup (no aout, no digital out, no tpd), then extend... this allows for quick endorphin release (not necessary to solder up everything) and to test early :)

Have fun building it! :)

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Looking good. For the TPD, be aware that this will require some smd soldering - however, this is not a big deal, the parts are reasonably easy to solder anyway. Just make sure you follow the instructions in the Wiki.

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@mongrol - Thanks! I've been digging through build threads and the wiki for a few months now, just getting my head around what a full build will entail. Trying to plan a limit on features now so I don't get carried away later, and so I have a roadmap as I go.

@Hawkeye - Well, a single DOUT would definitely make my build much easier. :) I had been planning on doing everything procedurally, on a module-by-module basis, to make sure I don't throw something in there that borks up the entire build. And thanks for the tip about the TPD, I'm sure I would have done it earlier in the chain and made a mess with later additions.

Regarding the firmware rewrite for the QUAD_IIC boards - I'm looking at the board that @smashtv has on his site, and it looks like that's a stack of four 16F88 PICs, which leads me to believe they can each be configured as the OUT-only version of the IIC board. (Also just realized, these can't be chained, so I'll have to use J4A and J4B, with the QUAD_IIC board on J4A wired up for the 16x16+X BLM).

@ilmenator - I'm pretty comfortable with SMD, done a few low-grade projects in the past. There's also going to be a solid amount of SMD soldering involved with the BLM build I'm interested in, so by the time I'm done, I'll be a veteran. :)

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