Okay, so there are a couple of us on the board with datalogging abilities on our wideband controllers, and we would like to log the CEL signal so we can see knock if we have the CEL-knock sensor feature enabled on our calibrations. So here is the issue we need to resolve. The CEL signal is a ground reference, and we need a voltage signal of 0-5V going to the wideband. So we need to figure out how to somehow use the CEL ground refernce signal to get that voltage signal to the wideband, and it can either be a rising or falling signal, just as long as we can see a change in the signal and know that its knock. And yes I know there are pre-built units out there, but in true TM fashion I dont want to spend $100 on one when I know someone here can come up with a cheap easy way to do it ourselves. Put on your thinking caps and lets see what you've got