On Wed, 5 Dec 2007 13:51:27 -0600 "Josh Lawrence" <hardbop200(a)gmail.com> wrote: OK. You've confused me. What sort of knob are you talking about that isn't on a knob box? -- Will J Godfrey http://www.musically.me.uk

On Wed, Dec 05, 2007 at 01:51:27PM -0600, Josh Lawrence wrote: Mmmmmm... knobs... http://www.umop.com/art/kb008.jpg OK, seriously. I have for sale, a PCB with 8 rotary controllers, another PCB with 9 faders, and a third PCB with 8 drum pads and their rubber buttons that go with them, available to anyone who wants to use them for a MIDI or USB controller project. All you need is an Arduino, a soldering iron, and a multimeter, in order to build your own bad-ass controller with knobs. All three boards were salvaged from the M-Audio Axiom 49. AFAICT they all still work (it was the motherboard that died on the Axiom). I can scan pictures of them if you really like. Anyone interested, make me an offer, either for individual boards or for the whole batch. I need the money. I'll find a way to ship anywhere in the world; these things don't weigh much. -ken

On Dec 5, 2007, at 2:51 PM, Josh Lawrence wrote: First, as someone else mentioned, you plug these into a microcontroller. A popular one is Aurdino from the MAKE Magazine people. SparkFun also has some interesting and relatively affordable kits. Or you could use a CPLD or FPGA. This will be harder to a lot of people to use, but it can potentially do more, and they are also fairly affordable. The final choice, which I wouldn't recommend at all, would be to use a bunch of I2C GPIO or ADC chips connected to a USB->I2C adapter. While this may seem easier, I doubt that it really would be easier. Broadly speaking, you have two choices for knobs. You can either get pots or you can get rotary encoders. How you use these is fairly different. From a look and feel perspective, rotary encoders will turn forever, and they feel a little clicky (or very clicky). Pots have a start and end point, but they are completely smooth. From a more technical point of view, rotary knobs are switches. They send a up switch or a down switch signal. They can be hooked to a digital GPI port on a micro-controller or FPGA. Pots are analog and need to be connected to an analog to digital converter of some sort. So, the short of how you would do this would be to hook your buttons, switches, and rotary encoders to your microcontroller's GPI ports, and regular knobs to the ADC ports. Then, you would write a program for the microcontroller to send events out a serial port. Depending on the microcontroller, it maybe possible to configure a UART to be MIDI compatible and actually make it a midi connected device. OTOH, it may be more useful (and simpler) to just issue commands out a regular serial port and then have a program on your host computer that reads the serial port and issues OSC or midi commands in JACK. As for buying parts, check out: mouser.com (general catalog) digikey.com (another general catalog) sparkfun.com (hobbiest kits) or google for aurdino. BTW, while a microcontroller like a Philips LPC may look very nice, sticking to something like an 8-bit AVR may be simpler to get started with. But, that's not what I actually did.