Lasers are some of the coolest devices around. 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 ...

In this fun project an ultrasonic distance sensor is used to detect a “target” (i.e., a person, a cat, a burglar, etc.). The Arduino illuminates (blasts) the target using an inexpensive laser diode ...