toggle switch to give a pulse?

Question

hello,

im looking for some ideas for taking an output from a switch i.e. always on or always off, and getting a pulse output, but heres the crunch, we need a pulse when the connection is made but also when it is broken, changing the switch isn't really an option and we would like to stay away from PICs.

thanks in advance

ps. its all going to be low voltage stuff, the output we need will go from open to 3.5v to open

Answer 1

use a two input schmitt trigger Ex-Nor gate. one pullup resistor from +VDD to one of the inputs, one resistor between two inputs and a capacitor at other input and gnd.Place a SPST switch between first input and gnd.
So final circuit is +VDD > R1 > first input & switch & R2 >
R2 & second input & capacitor > switch & vapacitor & gnd.
you have to choose R1, R2 and C or trial and error for desired pulse width.

Good luck!