Analog2CV
Posted: Sat Jan 16, 2010 10:43 am
Capacitor and I are working on sending control voltages to hardware synths through normal AC coupled converters such as the A16.
What happens is a scope device is sending a constant waveform similar to a (very primitive) TV signal, when a certain negative value is reached then a trigger pulse sets off timers for 4 sample and hold chips.
the scope device is modulating those parts of the wave with your control signals.
sample and hold chips chips will measure the voltage of the wave at teh appropriate time.
It is looking quite good so far if it all works out i believe it will be able to respond in 1.5 mS to changes (with 689 HZ carrier wave) which is fast enough for all but the snappiest of envelopes. (scope envelopes default to 3mS, but can go as low as 1 on some devices)
Unfortunately I have no CV analog gear any more since i sold the revolution, but i have ordered 10 SEM2044 Chips and i am going to build a filterbank to test it with.
The reason I have provisionally picked that frequency is that it gives 64 samples per wave at 44.1k sampling rate, which should hopefully be enough to get a decent flat part of the waveform to measure.
The hardware consists of an arduino microcontroller board and a few other chips, and possibly an LCD to give feedback of what it is recieving.
I think scope uses a korg like V/HZ rather than volts per octave. hopefully that can be converted in scope with the help of some math genius
Here is the trigger outputs being tested at 1 khz. very stable. Capacitor is doing 8 steps per cycle but i think we can at least use the same scope device to control it.
If it works out, and there is interest (maybe a VST as well?) There are a few options for releasing it. seeedstudio has something called "fusion kit" where you can set up everything through them, or it could just be a bill of parts with the arduino code, with or without custom circuit board.
I do not expect to make any money except recoup the cost of any custom circuit boards i have made.
What happens is a scope device is sending a constant waveform similar to a (very primitive) TV signal, when a certain negative value is reached then a trigger pulse sets off timers for 4 sample and hold chips.
the scope device is modulating those parts of the wave with your control signals.
sample and hold chips chips will measure the voltage of the wave at teh appropriate time.
It is looking quite good so far if it all works out i believe it will be able to respond in 1.5 mS to changes (with 689 HZ carrier wave) which is fast enough for all but the snappiest of envelopes. (scope envelopes default to 3mS, but can go as low as 1 on some devices)
Unfortunately I have no CV analog gear any more since i sold the revolution, but i have ordered 10 SEM2044 Chips and i am going to build a filterbank to test it with.
The reason I have provisionally picked that frequency is that it gives 64 samples per wave at 44.1k sampling rate, which should hopefully be enough to get a decent flat part of the waveform to measure.
The hardware consists of an arduino microcontroller board and a few other chips, and possibly an LCD to give feedback of what it is recieving.
I think scope uses a korg like V/HZ rather than volts per octave. hopefully that can be converted in scope with the help of some math genius
Here is the trigger outputs being tested at 1 khz. very stable. Capacitor is doing 8 steps per cycle but i think we can at least use the same scope device to control it.
If it works out, and there is interest (maybe a VST as well?) There are a few options for releasing it. seeedstudio has something called "fusion kit" where you can set up everything through them, or it could just be a bill of parts with the arduino code, with or without custom circuit board.
I do not expect to make any money except recoup the cost of any custom circuit boards i have made.