We can use them to cut things, create laser light shows, and also as a rangefinder.[Ignas] wrote in to tell us about [Berryjam’s] AMAZING write-up on creating an Arduino based laser rangefinder.

The answer for [Owen Schafer] was to build it with parts ... The stepper controller is an Arduino Mega running the Marlaser firmware, though [Owen] admits perhaps a laser cutter-specific driver ...

Building an Arduino speed detector using IR technology to measure the speed of a moving object is much more cost-effective, ...