Perhaps second only to the power of flight, mankind has long desired to explore the ocean depths like whales or dolphins. While some humans have honed their diving abilities to the point where they can descend hundreds of feet unaided by equipment, for most of us going much below 10 feet means using air tanks — or even a submarine. Unfortunately, a full-sized sub is out of most people’s budgets, but you could instead make a model RC sub out of a drink pitcher, as shown in the video below.
Control for the device is via a canalized RC submarine, along with a pair of motor driver boards, providing a relatively easy way to actuate its two thrust motors from a distance. A linear actuator is also used to operate a syringe, which sucks in and exhausts water to change the sub’s buoyancy. One would assume that as it gets too deep, control would be lost, but in lake testing it actually performs pretty well after some trial and error — and the wise use of a rescue line.
The sub’s mechanical construction is also quite interesting, starting with its hull built out of a drink pitcher. The pitcher’s top is sealed with pipe tape and hot glue, enabling the attached internals to be easily pulled out to work on, and the fact that its clear should aid in diagnosis. Another important feature is the way the motor shafts were sealed, making very effective use of washers and o-rings to allow power transmission while keeping water out.