can window comparator work here?

Thread Starter


Joined Aug 9, 2006
Good day people.

I've got some problem doing one of my project.

And here goes,

I am building a touch base input device for my project. And basically i came up with this idea of using a window comparator for the application.

The list of component used:
- touchpad (is basically a copper tracing which is a open circuit at first, refer to figure 1)
- LM741 op-amp x 2pcs
- 1kohm resistor x 2pcs
- zener diode x 2pcs
- 7408 AND GATE x 1pcs

The result i wanted was that once i touch the touchpad, the output from the AND GATE must be a logic 1 and once i let go, it ouput must be a logic 0. (im comparing 6v and 1v respectively n' not 5v and 1v)

And i tried quite a number of method to no avail.

Am really quite stuck down by it.

Any help would be grately appreciated

figure 1: the touchpad
figure 2: before implementing the touchpad to the window comparator
figure 3: added in the touchpad to the comparator circuit