Measurement tools, like calipers and micrometers, are just as important as your soldering iron and side cutters. But if you’re still using a measuring tape for long parts, you are subjecting yourself to unnecessary frustration. Digital measuring wheels let you easily measure almost infinite lengths by rolling the device along. There are wheels like these on the consumer market, but you can also follow AGBarber’s Instructables tutorial to create your own.

In addition to distance measurements, this wheel has two other functions. You can roll it around the circumference of a round object, like a pipe, and the device will automatically calculate the diameter. You can also spin the wheel and it will tell you the RPM. We’re not quite sure what the RPM function’s application would be, but we’re sure that someone has a use for it. The unit is about the size of a typical measuring tape and has a big battery for portable use.

The BoM for this project is extensive, because it uses a custom PCB. But most of those components are simple resistors and capacitors. The standout parts are an Arduino board, a 0.96″ OLED screen, a LiPo battery, a TP4056 LiPo charging board, and a computer mouse scroll wheel encoder. That encoder attaches to a gear which the device’s outer wheel spins. It tracks rotations and gives an accurate distance measurement. The body of the tool, the outer wheel, and the gear are all 3D-printable.

If you want a fun project and a convenient way to take measurements, this is the gadget for you.