electronics for a diy ribbon controller

[Puentstein at aol.com]

Greetings,
After fumbling around with a 2 foot long piece of metal, a bit of vhs tape,
and a 9 volt battery, (for now), this hookup 'seems' to work right (measuring
variable voltage off the tape):
                          
                          + --------------------meter------------------ _     
                tape:    ____________________________  _                      
                            ___________________________    >-----voltage
source                        
         metal bar :   I___________________________I  +   
                               
 ...The tape voltage appears to change "exponentially" as in the higher up the
tape you move your finger the quicker the voltage increases.  Is this the
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?    Sorry I'm all
questions but my objective is to learn something/build a stand alone
controller without frying the innards of an old Moog.
Thanks for any info, Randy