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Old 08-28-2008, 03:24 PM   #553 (permalink)
jmilk
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CANBus

Ok, I've been reading many of the pages on here. I like the idea -- I had a similar one before even reading this thread, and had the arduino in mind as well. My initial thought was to tap into my car's "trip computer" as that necessarily has all the fuel-usage and vehicle speed info available. The thing it's missing is the "immediate" mpg display -- it only has avg mpg, which gets to be relatively useless about half-way through a tank. I would also REALLY like to log average mpg per driver.

So I cracked open the overhead console and found that the trip computer has all of four connectors -- power supply and two for data. I'm 95% certain that it's the car's CANbus interface, which broadcasts vss, fuel, throttle position, etc.

Considering that CANbus (and some variations) are avaiable on the OBDII connector, why don't we just tap into that interface? The values are calibrated and should prove sufficiently accurate. Additionally, there's a line of AVR chips with build-in CANbus interfaces out there, and the prices are within the range of the ATmega168.

Any takers?
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