With CNC machines, getting the best results depends on knowing how fast your tool is moving relative to the workpiece. But entry-level CNC routers don’t often include a spindle tachometer, forcing the ...

[Jared] sent in this optical tachometer by [Mike Freeman]. The write-up and code requires a free registration, but if you’ve got a use for it, it’s probably worth the hassle. The zip archive includes ...

Tachometry, the measurement of the speed of spin of rotating objects, is a common application. Some of those objects, however, have quirky aspects that make them extra interesting, even scary. One ...