Using Autometer Electric senders to trigger warning lights December 15, 2009, 04:53:40 PM I have both a electronic FP gauge and a pyrometer I would like to monitor. My though is I should be able to T a LED and SCR (perhaps a better idea for a gate?) to trigger a LED if one of the gauges fall below a certain level. i.e. fuel pressure, ideal level is 5-6 volts depending on boost if it drops below 4.8 I want to trigger a LED mounted next to the gauge to turn on. Any Ideas on how to accomplish this? The pyrometer would be a high side gauge so I think I can set this to trigger simply with an LED and a known threshold voltage level. its the below a level and turn on that I am having trouble with.