How Does a Breathalyzer Really Work?

Ever wonder how a breathalyzer works?

We all know how simple they are to operate, but I'm talking about how they really work. You know, the circuits and diodes and microcontrollers and such. 

Turns out, the curious man behind the Applied Science YouTube channel, Ben Krasnow, posted a video recently where he takes a deep dive into the innards of a BACtrack Keychain Breathalyzer to see what makes it tick.

Fascinating video--especially for those of us living in the breathalyzer world.