What I want to do
Some people don't drink water from the hot tap, because its sat in pipes and has more heavy metals. But could we use the 555-based <$5 Coqui sensor?
My attempt and results
First we had to let them equalize in temperature because that'll affect conductivity. Then we made a more durable version of the Coqui soldered on a perforated circuit board instead of a breadboard.
Questions and next steps
How much is temperature a factor? Can the Coqui compensate for temperature?
Why I'm interested
This'd be a great first thing people could do with such a sensor... A Hello World, and one which would have real environmental health repercussions for anyone drinking their tap water.