An awful lot of hackers and Pi enthusiasts have banded together to create an deep water monitoring system that takes pictures and records video. At a depth of 50m (and a maximum tolerance of 100m), this is easily one of the coolest Raspberry Pi projects ever.

For an overview of the project, head over to the Raspberry Pi Foundation website where Clive Beale has written an extensive piece. For details of how the devices were deployed, take a look on the Chagos Trust website.