Submarines and submersibles (small subs) provide their operators with some capacity to interact with the outside world. However, you run into problems when scientists want to add a new outside tool that they can operate while safely inside. Just drilling control wire holes in the hull does not work – given humans’ pesky need to breath and the crushing pressure of deep water.
The students of CSU Monterey Bay Professor Steve Moore’s robotics class came up with a solution, and in so doing created “Squid Disco.”
CSUMB’s mascot, the aptly named Monty Rey, is displaying proof of concept. Here, the otter peers through the window of a submersible. Light waves are able to travel through the material, even as the submersible’s window holds against tremendous pressure differences.
Students in Professor Moore’s class asked: If this is true for visible light, shouldn’t it work for infrared light as well? Fortunately, most households have an infrared device close at hand – the TV remote.
Students Josh Ambrose, Jessica Schulz, Katie Beck, and Daniel Gossard built the “Squid Disco” device that takes these remote infrared commands and processes them to send back a series of light signals.
Understanding how a device should work and proving that it does work are two very different things. The light wavelengths used by TV remotes are strongly absorbed by water, much like visible light traveling through dark coffee. For infrared to control “Squid Disco” on the outside of submersible, the light waves need to reach the device while still carrying the commands.
Another real world challenge is that the self-contained electronic device needs to function properly in electrically conductive salt water under incredible pressure.
Testing “Squid Disco” requires two things: a large body of salt water and a submersible. The first is rather easy in California, given the 840-mile Pacific Ocean coastline. The second takes the help of the Ocean Gate Foundation and its submersible, Antipodes.
On October 22, Ambrose sends the infrared commands to the device during a 60-foot dive aboard the Antipodes. “Squid Disco” works perfectly. The device responds to remote commands with the appropriate light signals.
The crew confirms the results at a depth of 932 feet, proving that the device casing – filled with non-conductive, non-compressible mineral oil – is able to withstand the enormous pressure.
Squid miss the party, but a large sea nettle jellyfish (Chrysaora fuscescens) gets its groove on.
Note: video, additional photos and more information about the CSUMB underwater light show are available here.