BICYCLE COMPUTER for easy EOC
 

I installed a SIGMA bike computer (ca. USD 49.-) with a magnetic sensor attached to the left front wheel for accurate speed and distance reading. The bike computer (operates on one CR2032 battery!) not only accurately displays speeds up to 199,5 km/h or 124 mph but also the exact distance driven (of course the circumference of that wheel has to be properly measured and inserted into the bike computer!).
During EOC with ignition in intermediate position, your car odometer will not add mileage which means your car might achieve a better resale value. I currently do 10-15% EOC -but- depending on the vehicle (stickshift subcompact with easy technology!) this value can be pushed to 40%plus by expert hypermilers...

Welcome to EcoModder.com :)
This is a good idea, since most new cars have tons of electronics, instead of the good old mechanical odometer.
My advice would be to attach to a rear wheel. The front wheels usually go a longer distance because of turning and slipping.
Calibrating a bike speedo is easy with a GPS:
First, set your wheel circumference (usually in millimeters) to what you estimate is right. Drive around with a GPS and then compare the distance with the speedo. If the speedometer is x% lower than the GPS, then input a circumference x% larger. The farther you go, the more accurate the calibration.

BIKE COMPUTER to record EOC
 

I have chosen the left front wheel in order to have the shortest cable length from sensor to bike computer (the computer is mounted in the forward left corner of the dashboard). After measuring the wheel circumference I calibrated the unit on the autobahn on a 25 mile stretch with highly accurate distance readings on the meridian. GPS, of course is a good calibrating option, too.
The front wheel (drive) slip is neglectible while hypermiling (except for icy surfaces!).

Great idea!

Welcome to the forum.

Good to see the Swiss expertise with instrumentation is still alive and well.