electronics for a diy ribbon controller

[Paul Maddox]

Randy/Paul

>>Greetings,
>>After fumbling around with a 2 foot long piece of metal, a bit of vhs 
tape,
>
>>correct way to wire one of these things??   Also, how can I get an 
"s-trig"
>>(zero resistance) whenever the tape connects with the metal?  
>
>.......well there is a non-electronic solution possibly.....
>if the whole bottom metal bar were hinged on a spring or resilient 
support
>then you could put a micro switch underneath so that pressing down on 
the
>structure 
>closed a switch contact, giving the requires s-trig
>
>happy hacking from paul perry melbourne australia 


Ok, my daft sugesstion, Assuming you only want an Strig when you 
initially touch the ribbon, why not take the signal from the rod to the 
input of an opamp with a grounding resistor (1M'ish) and have the opamp 
configured as a schmitt trigger, so that when the rod touches the bottom 
of the tape (say .5v) it gives a gate out, and then use this to drive a 
FET (short-to-ground or STrig)? 

Worth a thought?

TTFN

Paul Maddox



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