I have bought a nice "emergency-stop-switch" (see pic :) ), which I wanted to use instead of my build in reset button. The problem is, that the switch is an "opening" switch, that means the two wires are connected, and if you press the button, they are not connected. Problem - reset button works other way.

Is there a possibility to have a small wiring that reverses the opening to a closing switch?
Posted on 2004-02-13 10:36:02 by beaster

Add a trigger Schmitt inversor and connect it input to a common joint made from a pull up 1K rezistor connected to the +Vcc source and connect you "normal closed" switch betwwen the resistor/trigger common point and the Ground (GND 0V).

This way your contacts keep the trigger's input at LOW value and the trigger generates an HIGH at output (since its an inversor).

When you will press the BUTTON the contacts will sepparate and let the resistor pull UP the triggers input.
And so the trigger will generate a LOW RESET signal (NRESET) ...

Just a simple inversor will do also but a TriggerS will avoid oscilations because of buttons contacts.
Posted on 2004-02-13 11:02:42 by BogdanOntanu