Paul wanted to have gauges instead of idiot lights on the instrument panel of his Jeep. The upgrade was supplied by A Howell’s Auto Wrecking in Ogden. In the photograph above you can see that the odometer is missing — and for good reason. Paul has to rollback the miles to match the odometer that is being replaced.
Why not just switch the odometers? Because the replacement has a trip meter. The odometer has to be rolled back 108,866 miles (256,673.9 minus 147,807.9) and Paul explains how it is to be done.
The odometer is driven by a small unipolar stepper motor. The motor is so small it can be driven directly by the Arduino using the example code found here at Arduino. The four pins on the motor were wired to the Arduino and swapped until the motor started turning.
Unfortunately the odometer’s maximum speed appears to be only 600 mph (10 miles a minute) and so it will take about seven and a half days to rollback to the original mileage.
The trip meter has to be disabled as it will eventually halt all backwards progress.
At the equivalent of driving in reverse at 600 mph it will take 7.5 days to rewind back 108,866 miles.
This video is a little out of focus but you can see the general idea.
Everything is under control, typical of one of Paul’s projects. But he’s forgotten one important event to watch for. What is it?
Update
Paul put together this live odometer streaming video which will rollback to the required mileage (147,807.9) some time on Sunday 24th October 2010. See if you can estimate the time, assuming it is running continuously.
Since last week additional mileage has been driven to bring the mileage to 147,950. The time this was reached was 10:48am on Sunday. Live stream discontinued.
