Hi !
I have recently bough an old rythm box, the Roland Tr77, and of course, there's no midi input (it's from 1972 !!!).
I have also this little interface : Circuitbenders - FR8L TR77 trigger interface DIY PCB
Do you think that an arduino is able to trig this card with a midi input from a keybaord ?
keyboard midi out > Arduino midi in > Arduino outputs to trig the circuitbenders card
The Tr77 needs 13 triggers inputs, do you think it's possible ?
thanks for help !
Yes, sounds straightforward. An Uno might do it, although I'm not sure it would have quite enough pins. A Mega would certainly be OK, or any other 5V Arduino with enough GPIO. You'd need the usual MIDI IN opto driving the Arduino serial Rx, and the outputs connected directly to the TRig board.
you could make them oscillate really fast by using the pwm outputs which can also be used as a trigger for modular synthesizers, and that would be great to sample. you could make different tempo programs where the pwm rate is similar to say 120 bpm , and select the programmed tempos in sequence with a physical button and digital input. that could serve as a drum sequencer not for notes but for osc sounds and rolls and the program you write would determine the drum machines output complexity. something like that you could make drum rudiments and patterns with some programming. I would suggest trying to use pduino and interface this to puredata that is where you can do the midi processing, in puredata and pduino that even though reasonably complicated might be easier than the optoisolator soldering job, (and would free up space on your arduino although I think pduino takes the firmata library and I do not know how big that is) and might be easier on the programming also - that would give you a direct connection to a computer rather than a hardware midi in jack. Puredata has oscillator objects that go beyond the typical pwm squarewave that is frequently complained about. Puredata would provide a better user interface for a gui for any arduino project anyway. if you wanted to make complex drum patterns with both arduino and puredata programming you would have the user interface for as complex a drum sequencer as you want to make. you could make note modes that trigger clusters like two sixteenths and a triplet when a midi trigger is recieved and output more complex data including pwm.