An Affordable FPV Submarine You Can Build to Explore the Depths
Max Imagination’s ESP-DIVE is a remote FPV submarine you can build for just $125 to explore the depths of your local pond.
It wasn’t long ago that underwater ROVs (Remotely Operated Vehicles) were tremendously expensive — the sort of thing that only militaries, universities, and famous film directors could afford. But technology has come a long way and now it is possible to explore the depths on a very modest budget, so long as you don’t need to go too deep. It won’t reach RMS Titanic depths, but Max Imagination’s ESP-DIVE submarine only costs about $125 to build and that includes FPV video capabilities.
ESP-DIVE is affordable because it uses low-cost off-the-shelf electronic components and mostly 3D-printed mechanical parts. Radio waves are famously shy about penetrating water, so this design follows standard practice and has tether going to a buoy for communication. Users can operate the submarine via a smartphone interface, which also displays a live FPV video feed from a camera in the nose. The interface allows for control over the thrust, rudders, ballast adjustment, and even illumination. Because the hull is sealed to be watertight, there are wireless charging coils to top off the lithium batteries.
The most important component is a Seeed Studio XIAO ESP32S3 Sense development board, which includes a camera module. Assembly also requires a custom driver board PCB designed by Max.
Most of the sub’s design is conventional, but there are a couple of interesting traits worth mentioning. The hull contains several iron wheel weights acting as ballast to reduce overall buoyancy, but there are also two syringe-based pistons for drawing in and pushing out water to fine-tune buoyancy on demand. Then there are clever magnetic couplings for the rudders and propeller, so the motors can stay dry within the watertight hull.
The control system is also quite interesting. Unlike with a traditional RC vehicle, all piloting commands are digital and sent over Wi-Fi. The XIAO development board actually hosts its own web interface with all of the controls, which the user accesses by visiting that IP address in their browser after connecting to the Wi-Fi network. The web interface also contains settings for configuring the sub’s functions, which eliminates the need for a hardcoded configuration in the firmware.
If you’ve ever dreamed of seeing what lies at the bottom of your local pond, this might just be the most cost-effective way to find out.