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Hasselhoff Submarine
The Hasselhoff Bot is a small submarine inspired by David Hasselhoff’s cameo in the 2004 SpongeBob Movie. In the movie, SpongeBob and Patrick explore the ocean in search of King Neptune’s crown to cover his shiny, bald head and David Hasselhoff is the last “vehicle” that propels the two friends back to Bikini Bottom, where they return the crown to King Neptune. In a similar fashion, the Hasselhoff Bot is a small, user-steerable submarine that allows the user 99 seconds to explore an underwater environment in search of an IR Beam, mounted on the bottom of the tank.
Hasselhoff Submarine (left) and remote control (right)
User Experience
In its welcome state, the submarine spins in place and the remote flashes LEDs waiting for user interaction. When the user interacts with the joystick, the sub is set into drive mode and the user has 99 seconds to reach the target. The user may use the throttle, steering joysticks to control planar motion as well as the target depth knob to control the sub's depth. Once over the target, a blue light illuminates allowing the user to "land" onto the target. The user is scored on how fast they can maneuver to the goal. Once the landing is done, the sub resurfaces and resumes its welcome state
Submarine and Remote design explained by the team
Design Methodology
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The sub is powered by four waterproof thrusters powered by BLDC motors arranged radially. Two thrusters are used to provide planar control and two for ballast control. The motors are powered by a 4s1p 5000 mAh 21700 battery pack. All communications are executed via SPI. Processing, both on the submarine and remote is done using an STM32 microcontroller. The submarine is fitted with a depth sensor as well as an IR receiver. Waterproofing is done using gaskets and bolts arranged circumferentially. Electrical connections are passed via Deutsch and MPT connectors to prevent water leaks
Submarine CAD (external and internal schematics)
State Machine Logic​
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The submarine, remote and communications all operate on state machines where events are handled by linked lists. The remote uses a non-preemptive scheduler to add events to the linked list. Every command generated by the remote is sent to the submarine via SPI. Each SPI message is acknowledged by the submarine with an 8 bit submarine state which includes flags for target detection, land completion and sub status.
Submarine State machine
Testing​
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The submarine was found to be waterproof when submerged in a 50 gal water tank. Within this small tub of water, the submarine was able to run through its states and demo the full user experience. However, due to access limitations, the submarine has not yet been tested in a large body of water. However,
The submarine being driven around in a 50 gal tub. The sub was commanded to spin in a circle by providing only a steering input
Source Code​​