m00dawg
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Texas

Given some of the recent conversations around the ShieldBoy I made (see http://victimcache.com/hardware/shieldboy/), I finally got around to working on an all-in-one solution. That is to say a solution that does not require the Ardunio baseboards but is self contained - you simply pull out the Atmega368 chip off your Uno, stuff it onto the AB Advance and you're off.

Specifically the design goals are:

* Compatible with Atmega386/Arduino (flash chip on Uno, put in AB Advance)
* Streamlined (items not essential to the ArduinoBoy are removed)
* PCB MIDI Jacks or Pin Headers
* PCB Mount D-SUB connector Or pin headers for GameLink Cable
* Supplied by direct +5V (either from a GameBoy or using another stable +5V source on a pin-header or barrel plug)
* Standard form-factor for some hobbyist case (haven't decided which yet)

Where possible, to save space, where there is an option for a PCB mount or header, it may not be possible to use both. For instance, the pin headers will be on top of where a MIDI jack would go, so you have to pick which one you want to use for your needs. That way it caters to folks making their own enclosure (such as in my likely case for a rack) or can be made to fit in what will hopefully be a "standard" enclosure.

On the note of the D-SUB, I picked that because it was different from a DIN connector (to avoid confusing it with MIDI), easy to build the cable-side connector, and parts are pretty easily found and inexpensive. But I'm certainly open to suggestions. The goal is to be able to unplug the Game Link cable easily.

These are just some ideas and I haven't decided on much of anything. I do have a sort of rough draft schematic that is getting close to be complete enough to share (a bit confusing on which crystal oscillator the Arduino Uno schematics are referencing, among a few other things).

Thoughts or suggestions? This is something that, like ShieldBoy, I plan on sharing with the community so your input is fairly important to me!

syn
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It could be better if a pot can be added to control midi cc:)

Timbob
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Also, Dinsync would be nice. big_smile

m00dawg
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Texas

If there is room I could add a header for a pot or two. Curious since I generally only use LSDJ (and occasionally mGB), what are the pots typically for?

In regards to dinsync, I did some Googling and didn't really find a good explanation of why it would be better than standard MIDI for this particular use-case? I did find a project that uses it plus a USB/MIDI bridge chip, which could be useful. But since I am going to include both headers and sockets as an option, you could use an external USB to MIDI bridge (MidiBox now has a few options for making one rather inexpensively - I use the GM5x5x5 for my MIDI stuffs). That could keep things reasonably flexible, although at the cost of not having an all in one solution, I'll admit.

One of my thoughts for my own setup was to setup a rackmount version of a few of these things and then have an internal USB to MIDI bridge. I'm not sure yet what the max current draw is but assuming I can also power it over USB, that's probably what I'll end up doing. So basically I'd have a USB port on the back, some D-Subs on the front for the Game Link cables and I'm good to go.

m00dawg
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Texas

Here is the first board layout I came up with. I lost my damn Mouser paper catalog somewhere so I haven't yet found a case. So I'm sure the layout will change, but the idea is there. Thought about designing a case using Pokono as well.

Those LEDs you see will be bent 90 degrees so that pop out the side where the button is. It's sin pots or Dinsync at least for the moment but working on this board did help me finally figure out what was wrong with my first design (ShieldBoy) - the MIDI Out pins were reversed. Oops. So that's fixed here (as well as in the ShieldBoy build doc).

Still to do is making sure I'm not missing anything important for the micro-controller and probably wiring something up on a breadboard so I know the schematic is sound. I may also put a bigger electrolytic cap (or add more smoothing caps) since there is some room left-over. Probably inconsequential, but I worried about how the GameBoy's sound might be affected by dirty power if using external 5V input.

m00dawg
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Texas

Put some additional time into the design. I have since moved to a more rack-centric solution and so I have swapped the SIL headers for DIL ones as those are easier to make and generally more reliable. I also made what should be a 1U rack friendly control surface for the LEDs and button. The GameLink cable will then connect via DB9 connections on the front of the rack. The board is only a tad larger this way, although I am debating on making a board just for my specific needs (as that would save space and, thus, cost). Anyways here are some pics:

http://victimcache.com/wp-content/uploa … ABA-IO.png
http://victimcache.com/wp-content/uploa … A-v020.png

Design is still untested but I plan on buying parts and putting things together on a project board to see how things go. Mostly just worried about picking the right crystal oscillator - everything else is pretty straightforward pulled right off the Arduino website.

herr_prof
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why does it need a full 1ru? maybe stick it in a 1/2 ru?

Nullsleep
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Tucson, AZ

Glad to hear you're working on a rackmount design.  Eurorack option might be nice as well.

m00dawg
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Texas

Actually my full design is going to be to have half of a 1U rack for 2-4 ArduinoBoy Advance's and the other half for the guts of an MBSEQ (Part of the MidiBox project) along with BPM and STEP read-outs. So it's effectively like a half-rack.

I couldn't find any good half-rack options that were reasonably priced. In fact, even full 1U enclosures were expensive for what you get and, at least in the US, seem to be rather non-standardized. As a result, I am using 1U shelving to mount stuff with custom front panels (either sitting in front of the 1U shelf or on a separate control surface panel if a particular synth needs more than 1U of control surface elements).

If all this works out, I'll be happy to share my results! I have other things I need to work on for my live rack, but the ArdunioBoy Advance's will come first so I should know pretty soon how it will all shake out.

If anyone is curious about how I'm planning our whole live rack, just ask! But I thought I would stay on topic. I will say, the rack shelf idea seems to be making lots of things SOO much easier.

herr_prof
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Yea I was going to suggest a rack sized enclosure and a shelf too.

There is also this too:
http://www.rackmount-devices.com/main.h … e=021-1800

Theta_Frost
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Milwaukee, WI

Nullsleeps eurorack suggestion was interesting.  Even if you don't design it for that, I might buy a PCB and stick it in my eurorack.

kitsch
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matt's mind

eurorack.

doing this wink

m00dawg
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Texas

Holy crap, you've made my rackmount dreams come true! I've been looking for just an online store like that for a LONG time! That is going to come in handy - thanks a ton for the link!

As far as a Eurorack design, that's something I'll have to think about. I have some existing gear that might not quite fit in that format so well. Reminds me I need to look into that further for when I build an analog modular rack though (YUM!)

Either way, the board layouts about could be used for something like a Eurorack with minor modifications I think, although I haven't designed anything for a Eurorack yet. I suspect using the main baseboard with some modifications might be the best option.

m00dawg
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Texas

So this sort of escapes the Eurorack concept I bit I think, but here is the smaller header-only version I have made:

http://victimcache.com/wp-content/uploa … ck-030.png

I am using headers for everything because all my MIDI connections to the ArduinoBoy's will be internal to the rack, as will the control surface elements. The GB Link will still be connected via  DB9 mounted on the front (even found DB9 connectors that work just like the crimp-DIL headers so that will make things easy).

The smaller size lowered the cost of having the board made via OSH Park (formally DorkBot) from $30 to $18 so I think that is worth it.

That said, I found an issue with the RESET pin for the old schematics as well - it needs a pull-up resistor to 5V so that would need to be back-ported to the other board layout as a heads up to anyone wanting to use those (if so, let me know and I can fix it or just hand over the Eagle layout and schematics).

m00dawg
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Texas

So perhaps I'm coming around to the Eurorack thing a bit. Still focused on a 1U format but I realized I don't need a 1U shelf for this as the main board can be mounted right behind the control-surface board. Fewer cables this way and everything is still well secured (at least to the front panel) with the only downside I see being that the chips and headers will be vertical and that makes me wonder if a nasty fall might unseat things.

Still working on the boards but I'll share them once they are complete.

m00dawg
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Texas

It's alive! Boards finally came in yesterday so I stayed up late last night putting together my latest version, found below:

http://victimcache.com/wp-content/uploa … Action.jpg
http://victimcache.com/wp-content/uploa … ck-040.png
http://victimcache.com/wp-content/uploa … IO-020.png

After having physically put the thing together, I found a few parts that can/should be flipped to the opposite side of where the silk says to place them. I also was not able to test MIDI OUT since I thought I had an extra DIN connector. Doh. But otherwise it works like a champ!

I don't have a prototype of my panel yet but since this design seems to work, that will be the next step as well as getting some mounting hardware to keep the thing more secure. The board layout has options for MOLEX connectors, but I just use SIL pin headers and will probably just use hot glue to keep the connections secured since crimping MOLEX connector-pins appears to be a rather big pain in the ass.

It's also the first board where I used a power plane in addition to a ground plane. Didn't notice really any difference, other than things working as they should (and using a power plane made routing easier).

Anyways this is what I've come up with. Should work well in a 1U format as well as a Eurorack (maybe with a few small modifications).

I will write an article soon up on our band website about it with the schematics and things, but if you want those sooner, just let me know and I can put them together sooner.