MIDIbox

This is the place to come when it comes down to my activity around MIDI and midibox.

Über-nerd from Germany, born Jan 1982. Studying computer science, had professional training in high-frequency analog electronics, audio signal processing and digital circuitry. Heavy EAGLE user. Programmer since the age of 8, starting on Commodore 64. Languages include C/C++, C#, Java, Basic, Python, Perl, PHP, assembly (8085,8086,PIC16, PIC18,AVR), SQL and many more. Beware! I'm an Apple user, but have a comfortable foot in all three worlds (Mac OS, Windows, Linux).

I've been actively involved in the midibox scene since 2007, but had been watching the project since around 2005 before. Since I grew up with the Commodore 64, naturally the SID was my entry point :)

I built an MB-6582 in 2008.

NOTE: Insert photos here!

This is the real-world MIDI project I'm in the process of building right now. It incorporates two 61-key manuals, and a lot of digital and analog controllers. This project is not based on the midibox hardware platform. It uses two ATmega32s and one ATmega2560 instead. The mega32s act as the keyboard matrix scanners and communicate with the mega2560 via USART; the mega2560 handles all the calculations and control surface I/O as well as analog signal handling plus two MIDI in/out pairs.

All controllers as freely assignable to CC, RPN and NRPN signals. Analog controllers include two joystick controllers and a ribbon controller based on flat touch potentiometers (more on this part of the circuit later).

At the moment, I am assembling the chassis, the electronics part is almost finished and programming is well underway. I expect to be done with it in spring 09. I've documented the becoming of this monster with my camera extensively so far, so expect a bunch of photos soon.

This will be using basically the same hardware as the Keyboard, so this is mainly a programming task - and it's in fact the elder project of the two. First stage is developing a 4×4 hardware router using only a single microcontroller, if that works to satisfaction, I plan on expanding to using two, interconnected via SPI for rapid data transfers. The routing table will be easily set up by using a matrix very similar to the one on the mbsid. nILS suggested use of a touch screen, which I think is pretty interchangeable since there is no real difference between switches and phototransistors.

This is in early concept stage, and atm just an idea I tinker with. I like the idea and concept of the midibox sequencer, so maybe I'll decide to abandon this and build a proven solution instead… Anyway, this one is the third “project” based on the mega2560 hardware (if it's ever done). As I said, I like the concept of the MBSEQv3, but I find it quite hard to use from what I've seen and read by now, so I started doodling in aim of a more entry-level friendly UI.

Some random sketches exist. I'm opting for a computer multitouch screen and use that for some musical applications.

What you can do in a big screen, you can do in the small, too… This is a research project regarding the use of FTIR technology to build a small multitouch pad acting as a buttonless control surface for microcontroller circuits. For this, there is no screen involved, and no camera either, like you would use in bigger setups used for computers like the one up the list. Instead, I plan on using LEDs as indicators and phototransistors as “button” replacements which function from the FTIR (frustrated total internal reflection) technology and will allow for “buttonless integrated display and controls”. This is quite cost effectively doable, yet I still need to figure out if it works for small-scale application.

The function principle of the sensing portion is described here: http://files.tachilab.org/intconf1900/tanie198410RVSC.pdf