re: $1,000,000 No, the pulse widths are changing, as is the duty cycle. The prototype keeps track of how long the injector signal is above(below) the threshold and how long in general.
P.S. I like the name OpenGauge
P.P.S. I've done a whirlwind tour of palm development options (it is CRAZY with options, waba, KVM, superwaba, mobilecreator, pocketC, hotpaw, cbaspad, etc, etc,). I am settling on the same one that OBDGauge was written in. It is a 180 meg download from
http://www.accessdevnet.com/ for Garnet (formerly palmOS). I was actually able to modify OBDGauge and run the modified version on my palm III.
I really want to do a comparison with the palm as an option because:
1. They are cheap and plentiful. I got mine for free. They are often on ebay for $10 apiece. With $6 worth of raw circuitry, microchips PIC, max232, voltage reg, misc, not including fancy cables/plugs, it can get the data it needs and be a complete solution.
2. They have a display built in, APA graphics display at that.
3. it is a touch screen, no external buttons to wire up, just add a widget to the screen and press it.
4. mine is backlit.
5. The support for palm programming is immense, the resulting device will be pretty awesome in that it can automatically log your fuel/mileage/date when you hit the refuel widget and hotsynch it to your desktop. Graphical displays will be a snap.
6. the garnet development system is based on eclipse (=awesome). We might even be able to integrate with OBDGague at some point and get more people looking at their mpg.