See build and code details at: [https://www.instructables.com/Digital-Measuring-Wheel/](https://www.instructables.com/Digital-Measuring-Wheel/) 

The digital measuring wheel (DWM) is like a traditional measuring tape, but instead using a tape, it uses a wheel that records the distance traveled as it rotates. The wheel runs around the outer body of the DMW, so to measure something you simply press and roll the DMW across your object.

This is great because it lets you measure in ways that would be tricky or impossible with a normal measuring tape. You can easily measure along curves, around corners, etc. Likewise, since you don't have to deal with a physical tape, you aren't really limited by length. The upper limit on the DMW is 9999.99cm (your average tape measure will do 25ft, or 762cm), which is only due to the screen size limits. At the same time, its minimum measurement is just about 1mm (0.04in), making it more than accurate enough to be useful. You can also instantly convert from cm to inches, displayed as both in decimal form, and rounded to the nearest 1/16" of an inch (configurable in the code).

I've also included a pipe diameter calculation mode, an inside corners mode, and a tachometer/speed mode (for low RPMs).