The cool part for us is that, not only do LittleBits use 0-5v for all their control and signals, they also worked with Korg to incorporate the classic MS20-style oscillators and filters plus envelope, mixer and a few other handy synth modules.
Although LittleBits do make a few converter and prototyping modules, as well as CV and MIDI modules, to connect straight to AE modules, we need to make some adaptors. So, this really becomes a DIY thread from here...
Unfortunatley, LittleBits send and respond to triggers/gates in a way that is not 100% compatible with AE because the triggers are carried by the control voltages by briefly dropping to zero at the end of a note
I think it's worth to find a solution for this CV/gate thing; should work also without a microcontroller. But what I don't understand: How is a gate sent here when CV is 0 volts?
Probably all pitches in the LittleBits environment involve some positive voltage. But that "trigger = 0V" thing is definitely some sort of Korg holdover, seems like, given that the MS-20 (and other Korg and analog Yamaha synths) uses a negative gate/trigger, sort of like the ancient Moog "S-trig" but without the annoying voltage sag problems that method had.
Maybe the solution would be some sort of comparator...when input voltage equals the same as the GND reference, then the comparator can fire a gate and/or trigger pulse...?
... the solution would be some sort of comparator...when input voltage equals the same as the GND reference, then the comparator can fire a gate and/or trigger pulse...?
Exactly like this! Quite easy thing to build. But it requires that "valid" CVs are always above 0V.
I have a couple of ATtiny85 around, so I thought I would use it to filter out 0v and just hold the last non-zero voltage and write that to the output as PWM and filter it in circuitry at the other end.
If I don't use the LittleBits sequencer or keyboard, the rest should be fine. I think the envelope module (envelope and VCA combined) will still trigger from a normal gate, as long as the signal goes low at some point in its cycle?
I was playing around with the LittleBits modules last night in preparation for some live gigs in a couple of weeks. They do sound very nice. Very much th eMS20 sound, as I remember it.
the CV-bits converter is github.com/littlebits/w18-CV which looks like it has a Freescale M26M6V (from squinting at the tiny circuit board with a magnifying glass- so I could be way wrong about that) to do some processing.
As I said, I'll probably use an AVR to filter out the 0v part and separate the gates, but it would be nice if there is a way to use proper electronics to do it.