DIY annunciator panel, current detector

 

 

 

Roll your own, good looking annunciator panels

 

http://www.aeroelectric.com/articles/Roll_your_own_Annunicator_Panel.pdf

This uses a reed switch nd coil in series with a load, to identify lack of current draw

http://www.aeroelectric.com/articles/Failure_Detection_and_Annunciation.pdf