Hi, I'm Lucy. I teach STEM to students aged 10+ in Ningbo, China — about a two-hour drive from Shanghai. In my classroom, students don't just learn about underwater robots. They build one, wire it, waterproof it, and dive it. GEN 3 is the third generation of the ROV they build.
Why design our own? A classroom robot has to survive beginners: dropped on the floor, flooded, wired backwards. It has to be affordable enough for a whole class set, and simple enough that a 10-year-old can understand every single part. Two earlier generations of trial and error got us here.
The build
- Frame: 20 mm PVC pipe and standard fittings. Waterproof by nature — and if a piece breaks, you just cut a new one
- Propulsion: three thrusters, two horizontal and one vertical — forward, reverse, turn, up, down
- Tether: 10 m. Power and control stay on the surface, so there's no battery inside the robot to seal
- Controller: handheld, with a real-time voltage display. At 9 V the system cuts power automatically — a rule we built in after watching students run battery packs flat
- Buoyancy: an EPE foam tube on top, trimmed until the robot hangs neutral in the water
Specs
Size 16.5 × 12 × 11.4 cm · Weight 1.5 kg · Max depth 5 m · Power up to 16 V via tether (bench supply or battery pack)
Steal this: the full frame cut list
We publish the exact cut list, so anyone can build the skeleton from hardware-store pipe — all 20 mm OD × 2 mm wall PVC: 3.8 cm ×2, 6.4 cm ×2, 10.2 cm ×2, 11.4 cm ×2, 12 cm ×4, 16.5 cm ×2.
And if you'd rather skip the sawing, we sell the pre-cut set and full kits — that's how our small education initiative funds the next generation.
What's next
The question every student asks is "can we add a camera?" — and I keep saying no: tether, cost and simplicity matter more at this age. Convince me I'm wrong in the comments.
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