Did anyone ever come up with a way to do this, i have the same problem and am looking for solutions. The crowbar circuit seems good, but there is a lack of info on how to properly select the components for anything other than 5V on the web.

 

Please do not tack your questions on another's thread. Always start your own.

Can you be more specific as to your problem? But if it's just a concern about accidentaly plugging a 5 VDC circuit into a 120 VAC wall outlet, use a connector that can't be inserted into a 120VAC socket.