# Nifty - OBD-II based Mileage Tracking



## Null (Oct 6, 2015)

I've been using TripLog for mileage. Mostly to just manually enter Odo readings and have a neat 'heatmap' of where I've been with the GPS.

They have a feature that allows you to pair the app with a Bluetooth OBD-II scanner. I never investigated it in the app until recently. Turns out I already had a compatible scanner http://www.amazon.com/dp/B00H9S71LW/?tag=ubne0c-20 (There are cheaper options that work just as well, see BAFX)

The OBD-II integration is neat. Most cars have a counter that indicates "Miles since DTCs (Diagnostic Trouble Codes) cleared" - This is a rolling counter that merely counts up miles since the computer's codes were last reset. The app makes use of this value to interpret mileage. You essentially tell the app what your Odo reading is on your display, and it associates that with the current value of the counter. From that point forward the app knows what your odometer readings are at all times. You will need to recalibrate (Tell app what your odo reading is) if you ever clear codes from your car... but this shouldn't be a common occurrence.

I've used it for the last week and it's been 100% spot on since calibration. All I do to track mileage now is start the car and plug in my phone to USB power. I then classify my trips end of the day at home. The rest is automagic.

AND! This solves the part about most trackers; the IRS doesn't care what your GPS says you drove. They want the Odo reading. Now this is automatic.


----------

