Dropcams are small camera units that can, as the name implies, be dropped off the side of a boat, floating to the sea floor below to take sensor readings and video. They can then float back to the surface automatically, all without the restriction of an inconvenient physical tether to the surface.
As spotted on Reddit, normally this type of equipment is much too expensive for the amateur sea explorer, but during an internship with Blue Robotics this summer, YouTuber WorkshopScience was able to construct a consumer-level model that can reach 1,000 meters in depth to take video in 360°.
The system consists of three basic parts: a float on top; a main unit containing lighting, a camera, batteries, and electronics; and a weight on the bottom. After a set amount of time, an Arduino Pro Mini triggers the device to burn through a section of nichrome wire, releasing the weight and allowing it to float to the surface. Video, temperature, and pressure readings that it took can be examined.
Whether Blue Robotics will end up selling a version of this dropcam remains to be seen, but it could certainly provide inspiration for similar DIY projects! An explanation of how everything works can be found in the first video below, while 360° footage from this rig is shown in the second.