Homebuilt ROV - Part 1
What I’m starting with
My previous homebuilt ROV (remotely operated underwater vehicle) was a simple PVC pipe construction, with a camera, light, and three thrusters. A pair of outdoor Cat 5 cables served as the tether, through which power for each thruster, power for the lights and camera, and video signal from the camera was passed. A control box at the surface consisting of non-proportional on-off-on switches controlled power and direction to the thrusters, and a small screen received the video feed through an RCA cable.
This system technically worked, but the clunky non proportional control made maneuvering extremely awkward, the frame frequently became entangled in sea life and underwater material, and the inflexible tether often dragged the ROV around and made it difficult to move.
Project Outline
This project seeks to build a new ROV with a compact hull, improved tether management, and a more sophisticated control system. Unfortunately, for this project, money is a major factor determining scope of features. I will attempt to use mainly materials I already have on hand and cheap off the shelf parts. In the future, if budget allows, I intend to pursue more advanced ROV projects with systems such as ArduSub autopilots, and sophisticated features such as companion computers, additional cameras, and better tethers (surprisingly expensive for long lengths).
As it stands, this project occupies a space of complexity and capability between the previous entirely analog system and an advanced system with onboard autopilot and computers running software such as ArduSub. The goal of the present project is to create a reliable remote vehicle capable of observing ocean life from marinas and shorelines, with a limited budget and mostly using materials I have.
The current prototypical design, modeled in Fusion
Cutaway view
Two of the three thrusters provide forward and backward thrust and yaw control (the only free rotational axis). The third thruster moves the ROV up and down, and is centrally located to reduce pitching moment. A microcontroller to and motor controllers to drive the motors is planned to be placed in an aft electronics box, filled with mineral oil, petroleum jelly, or wax to prevent crushing.
The next step will be to temporarily assemble the electrical system and test tether connection and control programming. When that is validated the hull can be finalized and the project finished.
