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.
This is in DIY territory but I'm trying to keep everything LittleBits-related in one thread to make it easier for someone to track down later.
I'm just planning a design to make using LittleBits better in the AE environment. I'm not going to address the triggering issue yet, as I think that will take more than my rudimentary knowledge of electronics.
The problem I want to address is the way LittleBits connectors carry both signal and power. As I've probably said before, every time you re-patch something, you hear a loud WHUMP! from the speakers - not a good look when playing live. Also, re-patching stuff is mechanically clumsy at the moment because you have to take the module out of the mounting board in order to access the connectors. On top of that, the LittleBits patch wires and connectors take up a lot of space and make it hard to patch in or out to other AE modules in the system.
I had noticed that I was not using my LittleBits at all in my patches, just because it's all a bit tedious compared to the ease of patching everything else. I tend to leave them all together as one separate normalised synth with just a CV input. Scr3w that! Time for a change.
So.... I have a cunning plan ...
Luckily, LittleBits sell the magnetic connector thingies (Bitsnaps™) separately and their terminal pins are standard pitch (I forget the size, but breadboard and stripboard etc) so I'm making something with stripboard and standard female headers to replace the ones that came with it. No pics yet, but the idea is to leave them plugged into the mounting board (the white ones and yellow 3D print one in the picture) and have the VCC and GND semi-permanently wired in with solid core copper wire to it's neater and more secure than patch cable.
Then the signal could be patched directly to and from the regular AE modules without any form of translation and without disconnecting and reconnecting power to any of the LittleBits modules.
The LittleBits Keyboard and Sequencer modules would not be directly usable with other AE modules, because of the cv/triggering issues discussed earlier, but the Oscillator (nice 70s Korg square and saw), Filter (MS10 style with CV for Freq), Delay, Envelope (AD with VCA combined), Mixer (2in 1out), Speaker, as well as all the sensors, microphone, motors, servos, fans, LEDs etc. would all be fine.