How does a breathalyser work?

Question

How does a breathalyser work?

Answer 1

When the chemicals in the breathalyser come in contact with alcohol, it changes and tells the machine that there's alcohol present. Of course, with more alcohol, more of it changes.

Not sure about the exact details, but there's some Chromium Oxides in the breathalyser and when it comes in contact with ethanol, the chromium becomes oxidized more and it changes color, signaling that you have a certain amount of alcohol in your breath.

Answer 2

When you drink, It goes into your blood. When you exhale, your lungs are expelling waste. The machine picks up on ethanol in parts per million. So sucking on a penny and c**p like that dosent work.  Its pretty simple.