MIT develops a sensor that can work underwater without a battery and send back data

TechCrunch ^ | August 20, 2019 | Darrell Etherington

[BenLurkin]

This could help set up an underwater Internet of Things, according to MIT, which would allow for real-time sea temperature and marine life monitoring, without requiring regular equipment and power swaps to make it work. Without that requirement, it would even be possible to set up networks of underwater sensors in the seas of distant planets.

The system, devised by MIT researchers, uses a transmitter that sends out sound waves underwater, which then hit sensors with embedded receivers, transmitting a tiny amount of energy in the process. The sensor then either uses that energy to answer back — or doesn’t, which corresponds to either a 1 or a 0, meaning it can effectively communicate in binary. The only energy required for this to work is the power stored in the sound wave sent by the transmitter.

Essentially, the system works by allowing piezoelectric resonators, which have been used in things like microphones for well over 100 years, to either deform in response to a sound wave, or retain their shape and reflect, based on information contained in any kind of sensor you might want to pair with the piezoelectric material. That sends back the binary signal, which can then be collected and interpreted.

[Paal Gulli]

This goes hand-in-glove with a project DARPA is known to be working on to use the ocean’s ambient sounds (snapping shrimp and such) as a low-powered active sonar to detect the passing of stealth vessels.

www.darpa.mil/program/persistent-aquatic-living-sensors

[Delta 21]

Preach it, brother.