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A hopping robotic camera for exploring the sea floor
What Bob does
I take "Bob" along when I go sailing out of Redondo Beach, California, USA. I toss Bob overboard and he sinks to the sea floor. This version of Bob can handle 750 m (2460 feet). Once there, Bob hangs out a while taking pictures and video. Every few minutes, Bob fires his thruster and hops to a slightly new location. After a preset time, he drops his ballast, rises and Bobs on the surface, waiting for me to sail over and pull him aboard.
The goal is to sample the Redondo Canyon, from near shore to the mouth at ~650 m depth. So far, this version of Bob has been down at 3 stations between 540 ft/165 m to 1,150 ft/349m.
10/17/2025 - Future dives are on hold due to a manufacturer's recall of the main instrument housing. I anticipate returning to sea in April 2026.
The Structure
Structure: Aluminum framework from ServoCity and other sources.
Instrument housing - 3" Cylinder from Blue Robotics
Camera Housing - Group B Distribution Benthic 2
Flotation - White syntactic foam rated for 1500 meters.
Ballast (not shown) - A "cattle lick" salt block released by a solenoid controlled drop rack. Salt dissolves in several hours providing a back-up emergency ascent method.
The Equipment
Main processor - Arduino Nano 33 BLE rev2.
Internal compass/magnetometer
Internal accelerometer
Internal pressure sensor
Internal & external temperature sensors
Water intrusion & fault protection
Data storage: SD card
LIDAR - TF Luna
Lighting - Twin CREE XHP70B LEDs run at 30%-75% maximum
Camera - GoPRO Hero 3 Black
Thruster - Blue Robotics' T200 set to 2.2 kg thrust
Power - Four 5000 mAh Li-ion 21700 batteries in series
Pictures
From the most recent 2 dives into the Redondo Canyon.
GOPR7550 - Trim.MP4Video
From the July 2025 dive into the Redondo Canyon.
Light flashes every 10 seconds - more info in FAQ section.
Bob hits the bottom around 03:40.
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