[sdiy] analogue guitar type controler thing

[studio271]

I was recently thinking of a way to get a gate off of a signal 
that was Vx (0V < Vx <= 10V, 0V = no note), and thought of a 
circuit that, in my mind, ought to work... First you buffer the 
signal with an op-amp (forgot what to call the config where you 
input to non-inverting and connect inverting to out) then you 
invert the signal (as in 10V -> 0V, 0V -> 10V, 7.5V -> 2.5V, like 
what was in one of the Modulus issues). After that you send both 
the inverted and original signal to the inputs of an OR logic 
gate. That way, whenever the original signal is anywhere above 
ground, the OR gate will kick to on (this might require a 
comparator before the first buffer set to trigger on, say 0.01V, 
or something, so that the inverter would not turn the 0V recieved 
when there is no signal to 10V). Hope this helps or someone can 
possibly clarify what I'm saying or improve it or something...

-Drew

At 09:52 PM 11/20/2002, you wrote:
>In that case I'd use the all analog solution... it would be very 
easy to do.
>The EFM KBD1 module and a handfull of resistors would do it.
remember I'm uber DIY so i don't want to buy any kits. also, I'm 
all the way over in new zealand so the postage and exchange rates 
are hell.

>Or how about a quantized ribbon controller ???
thats a really cool idea, especially if you had quantized and 
unqualtised outputs. quantisation should be fairly simple too... I 
was assuming that you would use it for your step sequencers? 
(rather than having (say) a switch with 12 positions...)

the important part with the tirggers it that I want to be able to 
hold them down, and have velocity, so strings-> follower wouldn't 
work so well could it would be more difficult get the gate, and 
you would have a maxium sustain time too.
 
cheers - Dom
 

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