[sdiy] complex gesture control ?

[Bluebear]

> A- Time based gate:
> If there is no change in CV after a preset waiting time, it goes
> low. Then, open the gate whenever
> any change in CV is detected. Close the gate again when no
> activity is detected for the w. time, and
> so on. (A comparator is not enough because you need to sense
> motion at any position=any CV)
>
> B- "velocity" + trigger:
> If you change CV fast enough, a trigger is sent, and also a CV
> proportional to how fast the
> CV changed (as in PAiA Theremax, see notes at Theremax pages)
>
> How could we implement this two ideas using comparators, gate
> delays... circuits we already have.
> Or build simple circuits... any idea wise men?

You need to look at op-amp integrator circuits - they produce an output
voltage proportional to the change in input voltage. With no change, they
output zero volts.

For your case A, you'd take the output from the integrator, rectify it (to
allow for positive or negative movements) and then into a comparator with
some low threshold. This would be your gate output, the CV would be the
joystick output (probably buffered).

For case B, you could do pretty much the same with the CV this time coming
from the integrator output (could go + or -) or the rectifier output.

Other alternatives would be to replace the rectifier/comparator with a
"window" type of function possibly.


--
       Jezz Brookes
http://www.bluebear.org.uk