diy mpg gauge

[itjstagame]

This is really awesome, finally some paved ground for a meter on my non-obd car. Can you think of a way that you'd use a serial or parralell port to capture the signals instead? Because I'd like to get more signals then just those two. Namely RPM because then I can show instantaneous HP and TQ and well and log and throw into StreetDyno.

Also one other nice thing that I'll add to this when I get it all working is an automatic crr and cid recording. I'm thinking choose a 'stop' MPH (like 20MPH entered through a text box) and then have a start button. I cruise to 70MPH, hit start and slip into neutral and let the vehicle slow to whatever the 'stop' MPH is. BAM, I know now exactly how long it takes me to slow down different thresholds, in fact instead of just 5 numbers at different speeds I have a full curve! Not exactly sure how to automate something to solve the crr cid equation based on this curve, but I'll certainly figure it out.

Do you think you could sample from the microphone jack AND line in at the same time? That might be easier than serial/parallel.