Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Any interest in developing an open source fuel economy gauge/computer?

jim-frank · 05-06-2008, 01:37 PM

This thread excites me, as well. However, I haven't the time to learn another language, nor the money for anything more involved than a few logic chips. I just finished a VB program to interface a couple of different geiger counters to my PC and laptop via a standard serial port, so naturally that route comes to mind.

I think a pair of (really cheap) comparator chips to obtain and clean up the pulses from an injector and the VSS, a rising/falling edge detector, and then using the cleaned pulses to toggle the DSR, RI, and DTR pins on an RS232 port might work OK.

I haven't read any comments on the retro analog approach, either. Something similar to an old tachometer circuit, using a bridge to balance injector pulsewidth against vehicle speed, maybe.

I'll probably play with one or both of these approaches, myself...

This forum is really excellent.

05-06-2008, 01:37 PM	#152 (permalink)
jim-frank EcoModding Lurker Join Date: May 2008 Location: western Colorado Posts: 59 ScabbySentra - '93 Nissan Sentra SE 90 day: 44.37 mpg (US) Thanks: 2 Thanked 7 Times in 6 Posts	This thread excites me, as well. However, I haven't the time to learn another language, nor the money for anything more involved than a few logic chips. I just finished a VB program to interface a couple of different geiger counters to my PC and laptop via a standard serial port, so naturally that route comes to mind. I think a pair of (really cheap) comparator chips to obtain and clean up the pulses from an injector and the VSS, a rising/falling edge detector, and then using the cleaned pulses to toggle the DSR, RI, and DTR pins on an RS232 port might work OK. I haven't read any comments on the retro analog approach, either. Something similar to an old tachometer circuit, using a bridge to balance injector pulsewidth against vehicle speed, maybe. I'll probably play with one or both of these approaches, myself... This forum is really excellent.