Open science hardware is amazing. You download some instructions off the internet, buy a bunch of components and build an actual scientific instrument. Now you not only know exactly how it works because you put it together yourself, but also how to modify it if necessary.

I love open science hardware. Over the past decade I've designed an open-source syringe pump, a hydroponics controller and an outdoor air quality monitor. I even wrote an academic article on open-source hardware for medical devices. I've also built open-source designs made by other folks, like this colorimeter designed by IO Rodeo: