TheAncientOne

In the custom car world this type of paint is called 'Flip Flop'. The thought of a bistable made of paint is rather disturbing, somehow.

I've looked at this some time ago - the I/O is probably the most expensive bit. You need to build an 8 input High audio frequency interface. I reckon that the generators for the outputs could be hardware, or small DCOs, but you still need 8 by audio range A->D systems. It's definitely possible, but it might take quite a lot of work. Due to the nature of the design, you might do it with a Core 32, but a better approach would be to use a dedicated DSP chip, which puts you in a different and frankly difficult realm. The good bit is, that if someone were cool enough to do the firmware, the rest of the project might just be possible. Other thoughts are, that with most modern audio A->D chips and DSPs, you'd have to go surface mount for the project. Once done, it could self tune, and be useful for a whole range of things. Sadly, the flexible display is a long way off and some kind of visual feedback is good. Having had a quick look at his code, it's quite complex, even though Max/MSP takes care of a lot of stuff, and would seem to need quite a lot of computing horsepower to run. There is a quote that there are two kinds of software problem: Trivial - I know how to do this, but I have no idea how long it will take, and complex - I have no idea how to do this. I guess this is in the first category, though it would take a long time, and be quite expensive for a DIY project at the hardware level, (by this I'm considering a firmware based solution, outputting MIDI or better OSC). A few thoughts, anyway.

Thanks Imp - I hadn't seen this one. I've built the ZX80/81 board, and have been looking a doing a 'Jupiter Ace' clone this way, (because I like FORTH). It's kind of pricey, but it looks a solid, totally professional job. Wish I could afford one.

I thought the same - especially having a full set of PC connections into the back of a keyboard based unit. No a reliability enhancer, that's for sure. Silly thing is, to me, an FPGA/SOC realisation of a '64, with some SD card storage could have been built for a lower price, and would have been way more fun, (not to mention the number of games it would re-enable). My other thought is of a re-made SID chip to go with it.... Historically, I have to say that as a games machine, the 64 was the boss of it's era. As a proper computer is was a bad joke, crappy implementation of BASIC, lame OS that had a negligible API, and any serious graphics had to be hand coded. I had, (and still have) BBC micros. Not enough RAM, basic sound, but one of the best BASICs ever written, a decent OS, well documented API, and support for loads of peripherals,(way more than any other device of it era). Oh, and discs that ran at a proper speed.

"No Bids" (Unless they did get their x0xb0x swap....)

American Commodore have announced a remake of the Commodore 64, using an Intel Atom. Seems to have built in '64 emulation, and will also run windows. Bet it hasn't got the SID though. Commodore Website

Just a thought: "don't lower the floor, raise the ceiling" - I had a similar problem on another device. My solution was to put a small spacer inside the knob, making it sit a little higher on the spindle. Of course on your panel it might be aesthetically unacceptable, but it's a possible answer, and a lot less messy than filing.

I agree absolutely, though some MIDIbox builders might be worried about working with the mains side of the power unit. Thing is, though, 78xx series regulators can fail and go 'off the clock' too. Some of the more modern low drop out regs have better fail protection, but where there is a risk of toasting 8 6582 chips, I'm going to be as careful as I can be. In an old 'big iron' minicomputer, the cost of a power supply failure would have been horrendous, especially as it was typical to find a linear supply capable of providing 40Amps or more at 5 Volts, which can burn tracks off a board without going into overload. As an aside, tantalum caps often fail to a dead short; in one old mini I worked on, all I could find of 3 failed tantalums was a black spot on the pcb, the power supply had effectively vaporised them. I agree with you about the power units, a replacement for the Commodore would be a very good idea. My view of the originals is that they were made to a price, (cheaply!), and the electrolytic capacitors in are now well overdue for replacement - except that it's not possible with most of them. I've never felt very happy with the idea of 'stacking' two outputs for 12 Volts, either. Perhaps a PCB could be run up for a better grade MIDIbox power unit. I'd still put an optional protection system on a new supply, if it was for my own use.

Perhaps we need to work up design for a supply 'crowbar' board. For those that haven't heard of one, it's a circuit that triggers a big thyristor connected across the power rails if the voltage exceeds a pre-set limit, with the intention of blowing the supply main secondary fuse. Very common in old computer systems where an over voltage could cause a fire, not to mention the repair bill for all the blown chips. I'd rather fry a PSU than my SID chips. There were off the shelf chips for the job. I'll take a look. I have something similar on my modular, where if one rail fails, the other is shut down too.

A quite beautiful sequencer, and I really like the panel design, very modern and clean. In the analogue synth world I have a pet hate of all those modulars that just have to look like a 1970's Moog, (or a 1970's Hi Fi system). Your design looks like a piece of up market test equipment, and I can tell from the layout that you put some serious thought into the way it would work for you. Great work.

The LM 3915 outputs will drive solid state relays. We once built some 3 metre tall VU meters for a night club, using mains bulbs. Later version added lamp pre-heat, (basically a small dimmer feeding a little current into each lamp to warm the filaments, and reduce fatigue failure). On the same tack, using filament heating transformers, you can build 7 segment displays from fluorescent tubes. 4 metre high digital clock, anyone?

If anyone can think of a better place to post this, please feel free to move it. I've had quite a long lay off from my music projects, and have started to do a bit of, (very lightweight), programming, again. I was looking at notes for some other real time work, when I found that the safety and style notes for the Joint Strike Fighter project were now in the public domain. OK no-one is likely to die as a result of a MIDIbox programming error, (though a crash on stage might make you wish were at least somewhere else), but I thought that there might be some good relevant info in it for us. Programming style is a very personal thing, but anything that I can find to make my real time work more robust sounds like a good idea for me JSF++, C++ Programming Standards Hope it's of interest.

I just spotted the Flip-Flop circuit with annotation "may use actual sandal instead".

Brilliant Idea! Just noticed the 'Arena' module - complete with diodes: "Two enter, but only one can leave". Randall Monroe is a genius. There is a 'Bunny' Cartoon about him too: Bunny on XKCD

I guess this is either circuit bending, or something from the audiophile world, (note the "expensive chip").

For those with an interest in ready made/commercial sequencers, Colin is on the launch pad with the successor to the legendary P3. Cirklon The P3 was originally offered as a kit/DIY, then became a commercial product, but proving, as with many other things like this, a rather expensive proposition to make. He also does a well respected MIDI interface for 303's, which allows, (at last!), MIDI control of the filter cutoff, as well as pattern download,and the usual MIDI control of the synth itself. I have no commercial connection with Colin, apart from the fact that he kindly sold me one of his last sets of boards then I could build a P3, (which I couldn't afford to buy). He'd probably be a bit horrified by my 'temporary' MDF front panel.

Another vote for the IsoPropanol here. Start off with pure IPA to loosen the flux, (an old toothbrush works well), then wash over with a mix of IPA and water, with an optional drop of washing up liquid. Rinse with pure water and dry with a hair dryer. This is similar to what some commercial PCB cleaning systems use, only they usually have solvent recycling built in. Acetone can easily dissolve the solder resist coating on some boards, and it can kill some plastic components. Polystyrene caps are especially vulnerable, (and expensive!). I wouldn't ever use it neat on a board myself.

That is so totally "Mad Max" - I love it. Cyberpunk engineering at it's very best. Please do video soon.

I've built two these, though I used veroboard. I thought, from the group, that the last PCB run was some time ago - could you link the URL you bought from? Was it a kit, or a built up version? Not a bad gadget. Details and Yahoo group here: One Bit Groovebox Another great 1 chip synth is the Fractal PIC synth: Fractal PIC synth thread and links here

Renoise back up after a hack attack.

If you are using the SmashTV DOUT board, it is laid out so that you can fit on of the ULN series Darlington driver chips in place of the output resistors, slightly more costly than individual transistors, but way easier to fit. SmashTV DOUT Page Smash captions it a relay driver, but it will happily drive the ground end of the LED's too. I've not checked my boards in detail, but Allegro and ST make High side/low driver chips that match in pinout, as I recall. ULN2981 High side (source) driver ULN2903 Low side (sink) driver Hope this helps

I found this today - how to make a rotary encoder from and old disc drive stepper motor. Too big and complex for use in (say) a sequencer, when you need a lot, but very good for uses like parameter setting, jog wheels and possibly DJ 'scratch' controllers. Good stepper motors would last forever in this mode, and have nice ball bearing mounted spindles, too. Rotary Encoder Using Old Stepper

Thanks Nils - never seen that utility site before - very useful. Hope Renoise hasn't died. Update - they now have a temp page up citing server problems; I'll just have to wait then.