Electronic – Resettable mechanical switch


I'm looking for a mechanical on/off rocker or toggle switch that can be reset to a default state and position upon the removal of power.

The application is in a vehicle where I want the switch to return to a default position once the ignition is turned off.

I know how to make such a switch using some digital logic and a momentary action, but the application requires better tactile feedback (and the ability to operate the switch without looking at it).

Does such a mechanical switch exist?

I found: Resettable latching switches
and http://en.wikipedia.org/wiki/Relay#Latching_relay, which are close, but do not physically put the switch back in the original position.

EDIT: To clarify, the switch is to control a GPS tracker. I want the tracker to be "on" whenever the vehicle is powered up, but the operator needs the option to toggle the GPS unit on/off while they're moving around. I don't want someone to accidentally leave the switch in the "off" position and have the next operator forget to activate it. It's vehicle-voltage (24V in this case), low current (10's of mA).

Best Answer

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Maybe try one of these. You could have a cap charged to 5V, a depletion-mode fet that is held off when your power is on and dumps the 5V charge through the coil when power is off? This would allow the switch to manually be reset even if power was lost and not purposefully reset.

edit: If it just needs to pop "ON" when the car turns on, have "ON" be the reset position. When the car turns on, have a circuit that momentarily 'resets' the switch to the "ON" position and then the switch will be toggleable.