Circuitbenders Forum
Circuitbenders Forum => Drum machines => Circuitbending discussion => circuitbenders.co.uk CB55 - DIY Boss DR55. => Topic started by: Altitude on April 14, 2015, 08:25:24 PM
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Gents,
I'm looking on designing a control surface board based on mods mentioned here as well as an integrated midi to trigger interface. Have a nice size Hammond enclosure figured out as well but what I could really use (and this is kind of asking a lot) is a board file or some support for locating the headers and patch points so the CS could be attached with vertical SIL jumpers to the individual outs, trigger header, etc.
Thoughts? comments?
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iirc there was a board overview in the building manual, and also dimensions must be somewhere around?
hats off to your passionate enthusiasm, but i would suggest to build the mods as a prototype first before making a dedicated board from this, as sometimes things need to be tweaked or can be optimized, that is a pita on a finished board.
also adding the SIL jumpers is not really easy as some points are quite hard to access, and given their "far apart" spacing they will be very hard to solder into the right spot and are also prone to breaking. possibly it is easier to add them to the bottom layer and turn the board around. mind you also need quite a lot of space for the pots and jacks in the casing. the one i chose for my build is the minimum height for large TS jacks with pots on top.
and then there is the layouting, i think even with a two layer board you will have a hard time to route the signals to the pots (in a sensible order), and also you would have to be very careful not to run certain traces in parallel or too close to each other, it is quite easy to create a feedback loop if the wrong paths come together. (i also had to bend the wires in my build in some special order to minimize feedback whistling in the output, but it was possible to do)
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Next step is to make the mods on protoboard for sure. I have the header thing worked out though, the patch point jumpers are 0.2" apart so you can just take a 3 pin one and pull out the middle pint. Works like a charm. Only place that wont work is in the middle where there are 3 jumpers in close proximity but I think I have that worked out as well.
The daughter board is not an issue, I design high density surface mount boards regularly and build my own euro modules so I have all the parts needed to do this in a right fashion. The case I have is wider than the CB55 board so all the I/O jacks will be PCB mounted 3.5mm Thonkiconn (they match 9mm alpha pots height wise so everything can be mounted to the panel). If there is not enough room on the top, the side panels can be used for more I/O
The slickest midi interface I've found is this: https://obsoletetechnology.wordpress.com/projects/midi-projects/midi-to-trigger-interface/ (https://obsoletetechnology.wordpress.com/projects/midi-projects/midi-to-trigger-interface/) which is like 12 parts and they have the uC in SOIC or SSOP so I am sure i'll be able to fit it somewhere
Case wise, this will be perfect: http://www.hammondmfg.com/pdf/1455J1601.pdf (http://www.hammondmfg.com/pdf/1455J1601.pdf)
I've used these cases for other projects and they are slick and cheap. I just send off the panels that it comes with to CNC which saves some money there as well.
I'll post my progress as I go along here and see where it takes me :)
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That obsolete technology interface has some serious problems with certain midi sources. I built it a couple of times, but when i tried to use it with anything that generated certain midi messages, it kept missing note on and off commands when you sent it more than one note at the same time, or not triggering one output when a certain other one is active, or any amount of other weird unreliability.
I'm not sure what midi messages it has problems with, but trying to run it from any hardware sequencer seems to cause all kinds of issues. If i recall correctly here was some discussion of it on the muff wiggler forum a while back, and nobody could get it to work properly.
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@Altitude Ok sorry then for underestimating... I didn't know what you're up to and in which scale, so i just mentioned the obvious issues one can encounter.
That case looks handy, I must admit that i always stayed away from these as i could not figure from photos that the panel can be slided out... Did not bother to look at the spec/datasheet then.
I posted my midi trigger solution in the CB-55 sub forum, which is based on a arduino compatible "deek robot" board. It comes with headers and can be soldered like a regular DIP integrated circuit, maybe would save some assembly.
Although i must say i run this board on a dedicated drum sequencer that really sends out only note on/off commands, i did not yet hardcore test it with midi clock and MMC/MTC things in the stream, will do that once just if somebody plans to use it differently. The code itself is very simple and runs in a quite short loop, maybe that could help the fast processing/recognition of all incoming data.
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Well crap re:midi to trigger. I'll keep looking, there should be something out there that is simple, any 8 bit uC should be able to do it but the last programming language I took was Fortran so I'll have to rely on adapting other peoples projects. I want to stay away from any type of dev board/ardunio etc. Maybe I should look at the 9090 circuit, that would also add velocity->accent
The cases work well. I used that case for a Beat707 and a Benjolin. Dont think you can do better for less than $20
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Here's another candidate: http://www.bartonmusicalcircuits.com/M2G/documentation.pdf (http://www.bartonmusicalcircuits.com/M2G/documentation.pdf)
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Just curious, why are you opposed to Arduino? That's what I'll be using for sure, as it seems ideally suited for a task like this. More than happy to upload my code once I get everything working.
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Just curious, why are you opposed to Arduino? That's what I'll be using for sure, as it seems ideally suited for a task like this. More than happy to upload my code once I get everything working.
Too big. I want no more than 2-3 chips and supporting parts that will go right on the control surface pcb
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I'm not sure what is involved in porting code between Arduino/arduino-compatible boards, but you might look into a Nano/Teensy. I think they take the same space as a standard DIP IC.
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standard DIP IC is too big. I need SOIC or smaller
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Isn't the ucontroller on the Barton circuits a DIP? I don't really understand, are you going to recreate that circuit from scratch with a smaller set of equivalent chips?
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its available in a smaller size, I was planning on contacting him about the firmware/getting permission etc. I have another source I am tapping to for this as well. Either way it will be SMD and included on the control surface board and will use a 3.5mm to midi DIN cable for the connections
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That sounds really sweet. Definitely keep us updated in that case, sounds like it could make for a very tiny and professional package. I'll be interested to hear how it all turns out; if you get a working solution before I have my arduino code ready, I may want to borrow your design ;)
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smd, no arduino... ok, maybe not my cup of tea then
imho there should be a lot of space, but i can relate to your plans to have things done as SMD. if i could solder SMD i would also use it all the time, for now it remains a mystery to me. especially i cannot understand what there is to like about it, unless you want to build a laptop ;)
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smd, no arduino... ok, maybe not my cup of tea then
imho there should be a lot of space, but i can relate to your plans to have things done as SMD. if i could solder SMD i would also use it all the time, for now it remains a mystery to me. especially i cannot understand what there is to like about it, unless you want to build a laptop ;)
Try it. I find it easier, faster, cheaper than through hole not to mention there are 100x more parts available. All you need is a fine tip, some solder flux, and tweezers. I have no idea why people have such an aversion to SMD, there is no magic to it and anyone who says you need an oven, masks, etc has never tried it themselves. There are only a couple types of parts that have to be soldered in an oven (BGA for instance), everything else can be done by hand. Hell, we do 0402 parts by hand under a microscope at work for prototypes. Everyone seems terrified of it until they try it then it's "oh, why haven't I done this before"
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so here's my board with the board to board jumpers installed
(http://misw.us/CB55pcb.jpg)
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So I have a new midi interface ready with kind support from Pete @ Midisizer:
Specs:
6 x trigger outputs, positive or negative going pulses (polarity configurable per trigger) with width 1 to 5 or 10ms
6 x trigger switches, momentary short to ground
8 level common accent output driven by note velocity
Learn switch: channel, trigger notes, reset to defaults after 10 secs
MIDI IN and MIDI THRU ports
2 x LEDs (MIDI IN, Triggers)
Persistent settings with auto save
Firmware update via sysex
Based on a ATmega328 with a bare minimum of parts (12 to be precise). I have it on bread board now and will be testing this weekend. After that, back to work on the CS board!
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Is that a custom thing, a thing you can buy, or is it a DIY thing on the net somewhere?
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custom but I'll get his blessing and release it here..
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So the prototype midi interface is built on breadboard and works perfectly. Very slick and simple to use, the learn function in particular is great, you simply hit the learn button and press 6 keys that you want to trigger the voices, that's it.
I has some debugging to do on my voice board (no noise, HH, and tone seems broken since it only increases background noise)
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custom but I'll get his blessing and release it here..
This would be awesome !
Do you still intend to release your midi interface someday ?
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Yeah, someday. Midi interface is done and tested but other projects have my attention right now