The flex sensors can provide an input to simple op amp circuit, where the
changing resistance changes the output of the op amp; (you'll need to view
the diagram below with a monospaced font in order to see it correctly.)
R1 | |
/ | |- |
+V <-\/\/\/\-+----| -- |
/ * | -- |
I in | -- ----+------- V Out
GND --------------| --
R1 is the flex sensor, R2 is the feedback for the op amp. (R1 could be any
variable resistor, BTW.) This is a classic example of a trasimpedance
amplifier where an changing input current (provided through R1) is
amplified and output by the op amp.
The gain of the circuit is -R2, so if R2 is 1000 Ohms, the gain is -1000.
The current at the point marked "*I in" is what is being amplified.
Remember that the output is not linear, but exponential because of Ohm's
Law: I = V/R, i.e., I (current) will grow exponentially as R (resistance)
For more help with this stuff, try the Radio Shack "Engineer's
Mini-Notebook - Op Amp IC Circuits" for examples and diagrams. Catalog #
276-5011. Please note that all scientific discoveries up to and including
quantum physics are covered by these little books you can purcahse at Radio
And now, we return to our regular program...
Mark Coniglio, Artistic Co-Director | firstname.lastname@example.org
Troika Ranch Dance Theater | http://www.art.net/~troika