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.

Unleash Your Inner Maker with Our Upgraded Sensor Modules Kit - Packed with 37 essential components for your arduino projects! Say Goodbye to Useless Modules - Our ...

With a sprinkling of hardware and software, he was able to get these cheap laser particle sensors working on his Raspberry Pi, and his work was ultimately incorporated upstream into Mycodo.