AVB2 / AV-B2

AV Brain :: Assembly gallery

This gallery documents the process of creating the very first AV-BRAIN (shown above). It was created to expand capabilities of my first live AV setup not including a computer (click here)

Feature list included:
- Following MIDI clock
- Recording and playback of 40 note long MIDI sequence
- Sending custom strings of MIDI messages in sync with MIDI clock including:
- CC information to fade video on Edirol V4 (synced to PAL)
- CC information to fade output on Edirol V4 (synced to PAL)
- CC information to fade video layers on Korg Kaptivator (synced to PAL)
- NoteOn data to trigger light flashes via MIDI-DMX converter
- Triggering audio loops on Korg ESX1 so they could be longer than the pattern played on ESX
- Triggering AR and Filter envelopes on Sherman Filterbank
- OneKnob functionality extending Korg ESX1's ability to only control one part at time. With AV-Brain you could learn a NRPN message, assign it to a knob and use independently of device's state.
- Fade up or down relative volume of all the channels on ESX1 - Filtering MIDI messages
- All sequencer tracks can be synced to 1/16, 1/8, 1/4, 1/2, 1, 2, 4, 8, 16 or 32 beats
- All sequencer tracks can be re-synced manually and still follow the tempo (to compensate for video delay)

All of the functionality has been present at some point, either in the prototype or in the final unit, however unfortunately only about 60% is present in the version of software available for download, some of it has fallen off during the transition from the prototype with its signifficant interface changes.

After deciding on the general layout I run into first trouble. DIN5 PCB mount sockets I bought had too thick legs to fit into the matrixboard I got. I had to make the holes a bit bigger.

Same as with prototype, I started by soldering in a transoptor for MIDI and few little bits it needs

On this picture you can see connections going from the Serial in Parallel out shift register, through resistors to the LEDs. Also, there are four buttons below, bnot yet connected to the Parrel in Serial out shift register

Second batch of buttons soldered in

More buttons and how they looked from the side

First jumper - I've decided to color-code all the conections, red means +5V power source....

... whereas blue is used for buttons and LEDs

Obviously soon there was more of them...

...and more...

...then the next layer was CLOCK and DATA sginals, represented by orange and green....

... so soon it all started to look quite....

... colorful

Finally female header pins were added so the board could be easily connected to Arduino

One bunch of cables is used to drive the LCD display while the other carries UART/Serial from and to MIDI, interface serial data, out, strobe and clock.

Of course there was a bit (couple of weeks) of coding involved. The code is not finished but it might be an interesting read for someone interested in building his own device like that. I had all the planned functionality written into the prototype but because the interface has changed a lot (more buttons instead of rotary encoders as were planned originally) I had to rewrite a lot of the code and before I finished I came to a conclusion that I am going to use RM1x as my sequencer for the time being so I don't know when will I be able to release a final one, so for the meantime: download version 0.18 (may 2010).

I was lucky to realize that all the circuitry fits nicely into a small lunchbox

Click here to see how it was supposed to sit in the setup.

You may also be interested in checking out The Harmonic Clock and its its build gallery, or the prototype build