Quote Originally Posted by angrysmileyface View Post
I am currently working on a project to add a second odometer to my vehicle. At this present time I believe it to be a series of pulses, however I do not know the number outputted per mile. Is it possible have the pic determine (perhaps count) these pulses initially so that I may use this number for my project? I don't believe there is a clock signal involved, and do not know the period. Any help provided is greatly appreciated. (And no this isnt a highschool or college project, I just want a second odometer for my car)

Thanks

SR
I assume you're talking about the digital odometers and not the old cable driven types.
On most of the dash panels I've seen, on the back, like right under the connector (a few times on the front), there's usually some writing saying something to the effect of "1320 PULSES PER MILE" ('88 Chevy Sprint). I don't remember the numbers for my other cars.

As far as calibrating (if needed), 2 methods come to mind.

-Drive 60mph, press a button, PIC counts for X amount of time or one minute, which would be perfect at 60mph since you'll also have travelled a mile, now you also have pulses per mile.

-Drive X mph, press a button when you pass a mile marker, press the button again when you press the next mile marker. Now you know how many pulses per mile (give or take). Maybe do ten miles so the 'give or take' will average out a bit.