I am a secondary school student who is participating in my first Hackathon and completely new to Arduino. This hackathon deviates from a typical hackathon as the period of time given to build solutions is 2 weeks and not the typical 24 hours. I've already built my solution with my team and have moved on to the judging process (it lasts for 2 days). Unfortunately, after the judges came to our booth, one of our gas sensors (MQ - 137) fell into water. Is it still usable or is our team goners tomorrow?
You need a 24 (or more) hour "burn in", followed by a sensor test, to know.
jremington: You need a 24 (or more) hour "burn in", followed by a sensor test, to know.
The important question is, do the judges know that? They are school teachers, not electronics engineers, no offence whatsoever intended!
Most gas sensors have built-in heaters. If you run it for the next 24 hours, it may dry itself out and start working again.
Hope you have a spare sensor as I'd be quite reluctant to switch one on while still wet. What should work is rinse it thoroughly in distilled water (most electronics can handle wetness just fine) to get rid of any minerals or other contamination of the water you dropped it in, dry it to the air (an oven at 80°C would be great, or whatever temperature it can safely handle), and switch it back on.
A chemist's way of drying things is rinsing it with acetone, then blowing it dry. That gets things dried very quickly and thoroughly, but I don't know how the part reacts to acetone.
A alternative trick to get moisture out (said to work well with mobile phones dropped in water) is to put it in a bag of uncooked rice, as the grains suck up the moisture.