praabjerg

If my countrymen can launch a big rocket on a low budget, then surely I can at least build a MIDIbox SID. There's also a "Pilot's POV" video http://www.youtube.com/watch?v=-rASHRBo9Rg. Short version: I'm sorry that MIDIbox can't take the first place, but this is likely the coolest hobby project I have ever seen. Long version, with some more background for the curious: Last thursday, apart from making a first post here about building a MIDIbox SID for a digital accordion, I was also eagerly anticipating the second attempt at a test launch of Tycho Brahe/HEAT-1X the following day. Tycho Brahe/HEAT-1X is the capsule/booster combination of Copenhagen Suborbitals. The Tycho Brahe capsule sits on top of HEAT-1X and is designed to hold a human being, shooting the prospective astronaut, Peter Madsen, into space and bringing him safely back down again. This was the first unmanned test launch, and there will be more of them in the coming years (scheduled for June each year), where they will be ironing out various problems and faults with the systems. You can see some of the problems in the videos. The two greatest so far: The rocket veers off course for a lack of steering, and the rocket engine still suffers from a certain amount of oscillations. This was anticipated, and there's already ongoing work to fix those. The reason the parachutes are basically ripped to pieces seems to be that the rocket veers off to retain a ballistic trajectory and never slows down enough for the parachutes to come out in one piece. Did I forget to mention: The seagoing MLP (Mobile Launch Platform) 'Sputnik' was custom-built pretty much from scratch, just like the rocket and capsule. And while I could forgive you for thinking it, this is not just a very elaborate joke by a bunch of insane Danish people :) They are seriously aiming for Denmark to become the 4th nation to shoot a human into space, after... Russia, USA and China. If they succeed eventually (and I have great confidence that if anyone can do this, they will), it would mark the first manned space launch in history by a non-profit, non-governmental organisation. These are literally mostly a bunch of craftsmen doing this in their spare time. Only three of them work at it full time. The rest of the team assemble in the HAB (Horizontal Assembly Building) after working hours and in weekends. The entire thing works very much like an open source/hobby project. They are very open about all the gritty details of it, and encourage input from the public, though much of that takes places on their Danish blog. But you can also find many of the interesting details on their homepage. The only cursory involvement by government money is the ships the Danish navy provides for assisting the launch operation each year. The entire thing is primarily financed through donations and through the support organisation, which currently has 400 members, each giving 100DKK a month. By doing that, we currently pay rent for the HAB, and for a number of the tools and materials they need. The above videos were, for instance, recorded by HD cameras partly paid for by me (and all the other members). And I love every minute of it. They should be an inspiration to hobbyists around the world.

Don't be too impatient. I'll do what I can, but it's likely going to take a while. I'm a computer scientist by vocation and have done very little in electronics the past many years. And what I have done was mostly digital circuits. I find those easier to understand :) I am also not a great accordionist yet. I only took it up again recently, after having been without accordion for about 15 years. But I'll get better, I'm sure. I'm just a little afraid that by connecting a digital accordion and a MIDIbox SID, I will inadvertently concentrate so much awesome in one place that it collapses into a black hole and destroys the world. But it's a risk worth taking, I think. Anyway, I'm still evaluating my options: On the VCA suggestion, I found some additional information here: http://www.mhennessy.f9.co.uk/preamp/analogue_research.htm So a digital potentiometer could perhaps also work. But for this part, I think I would still prefer some kind of boxed, premade solution, even if that's going to be somewhat expensive. We'll see. I know it's possible now, so I'll just have to build the midibox with an AOUT module and take it from there. On the MIDIbox SID itself (I'm going from this, mostly: http://www.ucapps.de/midibox_sid_manual_hw.html ): The sammichSID is likely out of the question, as it doesn't seem to have an AOUT module. The MB-6582 looks interesting, but also a bit overkill-ish. I don't need 8 SIDs for this purpose. 2 should be sufficient. There seems to be a number of extra modules involved in building the complete control surface, so I'll start with the minimal one, since I really just need the ability to set up two "SID instruments" for the accordion. Theoretically, I can just extend the control surface later if I want, by adding modules, and drilling more holes in the front panel ;) But the C64 case might turn out to be too small or constrained in the end. At least if I start extending with more modules. But I have a SparcClassic case which should be big enough for it, and future extensions (I am steadily cranking up the old-&-obscure-hardware-o-meter now). So it looks like it will be a modular setup, starting out with the following: 1 Core module. 2 SID modules. (For bass and treble instruments from the accordion) 1 AOUT module. (For bellows pressure indication to some external amplifier. Alternatively, for a digital potentiometer maybe a DOUT module could do the job. But I don't think anything prevents me from having both, really.) A minimal control unit/surface (DINX2 module and various other stuff) This would put the two SID modules in a "stereo" configuration on the same core, even though they wont really be used like that. But I am getting the sense that this simply makes the use of the two SIDs more flexible. It also saves me from having to build two cores :) Yees.. I think I can do this.

I did wonder if the 'crackling bug' would be a problem. A fix for that might be to simply use an 8580 or 6582 chip (where that bug was mostly fixed, as I recall. To the great annoyance of many). I could probably get my hands on one of those. And 4 bit resolution could maybe work, but yeah, it would certainly be noticeable. I'm not actually that much of a musician or hi-fi guy, so I just had to look up what a VCA was :) Certainly sounds like a much better solution. I'll have a look at getting one when I've finished the MIDIbox. Do you have any good suggestions? If it's just somewhere below $400, I don't mind so much. But I may get queasy if it goes far above that. Alternatively, it sounds like something that could be DIY built for simple functionality. Thanks. I'll probably try this with the volume, just to hear for myself if it really sounds that bad. But the prospect of affecting other parameters is interesting... It certainly sounds exactly like what I want :) Well. Then there's "just" the practical stuff left. I was considering a sammichSID kit, but if these only exist in limited supply, it's probably best to leave them to someone else. I should be able to handle the building of a MIDIbox, and I'd prefer to have the complete control surface anyway. I even have a non-functioning C64 that I have no problem cannibalising for a case. For me, the greatest issue seems to be how to make the front panel. It doesn't seem possible to order them finished. And working in metal or plastic doesn't appeal much to me. But maybe a plain wooden panel would work? And then I could simply burn the labels into the wood by hand... This might even end up looking quite nice, if a little primitive. But hey. SID _is_ technology from the eighties, so... I'll start by finding most of the necessary components/kits, and do some more reading. Then at the end of july, I'll be at a summer camp for a week with likeminded geeks, and likely access to better equipment. With any luck, I can at least get a core module with LCD running then. Many thanks. I'll be back later, complaining about all the problems I will surely have!

No, you read the title right :) So, I have one of these Roland Virtual Accordions. An fr-3x, to be specific. It's basically a keyboard with a bellows attached, bass buttons and integrated sound system. It also has MIDI output. All in all, it's an abomination on all that is good and holy about accordions. And I was wondering how I might make it play SID sounds, and considered briefly making sound sets to load into its registers. But this seems to be a strangely underdocumented feature. It would also be a terribly inflexible way of doing it. Then I thought "with all the crazy stuff people are still doing with C64 hardware, surely someone has built a MIDI syntheziser with the SID chip". And here I am. For this purpose, I want to build either a fairly simple MIDIbox with one or two SID modules, or maybe simply a sammichSID (assuming there are more kits available). I just have a few questions before I start hunting for parts/kits (please forgive me if you've seen some of them before, or if they seem stupid): 1. One of the points of the digital accordion is that by default, volume is affected directly by bellows pressure. And in the MIDI signal, bellows pressure is expressed through the CC11 (control change 11) channel. With a MIDIbox SID, how hard would it be to make CC11 affect volume for instance? (Or other properties of the waveform, come to think of it). Are these kinds of mappings a standard feature of the available software? In case it's not, could I do such tricks by modifying it, or writing my own software? 2. I still haven't understood the MIDIbox SID completely: The SID chip has three channels. How does this work in connection with MIDI input? Are MIDI instruments just mapped to SID channels? And what happens then if you send multiple notes on a channel simultaneously (i.e., try to play a chord)? Does it play only one note, or can it do some clever switching to make it sound like all the notes are played at once? 3. Somewhat related to 2: The treble keys and bass keys of the accordion are treated as two different MIDI instruments. Would it make sense to have two SID modules, and dedicate each to one instrument. If simultaneous notes can't be played on a single SID channel, this would in theory make it possible to play chords for instance, by using the three channels on each chip. Alternatively, maybe all three channels could be mixed to create more interesting sounds for the instruments? I'm most curious about the first question. It would feel somewhat pointless to hook up a digital accordion if I can't at least affect the volume with bellows pressure.