Scientists Send Text Message Using Vodka
voanews.com
voanews.com
Interesting, though. Seems like a series of breezes could seriously impact the communication, though, making the whole robots-in-the-sewer system not work quite so well.
Ahem.
https://news.ycombinator.com/item?id=6945800 (theverge.com)
https://news.ycombinator.com/item?id=6948140 (extremetech.com)
https://news.ycombinator.com/item?id=6943036 (laptopmag.com)
https://news.ycombinator.com/item?id=6942179 (sciencedaily.com)
https://news.ycombinator.com/item?id=6939145 (plosone.org)
https://news.ycombinator.com/item?id=6939133 (scienceagogo.com)
https://news.ycombinator.com/item?id=6935903 (arstechnica.com)
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjourna...
They achieved about .3 bits per second.
Components needed to replicate:
* DuroBlast Electronic Spray
* Arduino: https://www.sparkfun.com/products/11021
Alcohol Sensors:
* MQ-303a : http://www.seeedstudio.com/depot/alcohol-sensor-mq303a-p-549...
* MQ-3 : https://www.sparkfun.com/products/8880
* MR513 : http://www.cooking-hacks.com/mr513-alcohol-high-accuracy
So their setup is probably about $100
I might guess something like one bit, every 10 seconds?
Though I'm not sure if this particular example is of much use ;-)
As to smell, that was a stupid way to do it.
We can detect levels of lots of different things. Instead of 1 or 0 over time it would have made a lot more sense to say Ok, I need to be able to encode 140 characters with 37 choices (alpha-numeric + Space).
There is a humidity sensor, a Carbon monoxide sensor, an oxygen sensor, and a Carbon dioxide sensor. All are really cheap.
If you a tube and 37 levels that you release water, carbon monoxide, oxygen, and carbon dioxide to. You now have the ability to send. 4 characters at a time. Since alcohol sensors are cheap, we can use that for "parity" so we know that the message was sent correctly.