Hemisphere Project - Alang Babega

Hemisphere trash-collector ship prototype — The Hemisphere trash-collector prototype

The problem

A lot of trash in Indonesia ends up in rivers, which will eventually flow into the ocean. We aim to capture them before they pollute the ocean.

What we built

A prototype trash-collector ship, inspired by The Ocean Cleanup’s Interceptor.

Hull/frame: 2020 aluminium extrusions
Collector: a conveyor belt that scoops trash up from the water, plus a slider that moves along a track to position the catch
Electronics:
- ESP8266 hub: connects to Wi-Fi and listens to Supabase Realtime for commands
- Arduino motor controller: receives commands from the hub over serial and drives the conveyor and slider DC motors through L298N motor drivers
- Slider positioning: motor encoder with PID control, homed using a limit switch
Control: a tablet web dashboard (React + Supabase). A change on the tablet updates Supabase, the ESP picks it up instantly, and the Arduino moves the motors.

Remote control dashboard

Ship Controller web app on a tablet, showing dumper and conveyor speed, a conveyor up/down control, a 4-position slider control, and a red DUMP button — The Ship Controller, built to run on a tablet

A web app for driving the ship's collection system from shore. I built it in React and Vite, and Barra added tablet support.

How it works

There's no direct connection between the tablet and the ship. Both sides read and write one row in a Supabase table, and Supabase Realtime pushes changes as they happen.

tablet ──update──▶ Supabase ◀──reads── ship (ESP)
   ▲              (realtime)
   └──── live speeds ◀──┘

Controls

Conveyor: OFF / LOW / HIGH
Slider: 4 preset positions, from start to end
Dump: triggers the dumper
Live readout of dumper and conveyor speed

Build gallery

Fusion360 CAD render of the ship — CAD design process

Power supply being tested for the trash collector ship prototype — Testing power supply

Cable chain links being 3D printed in a Bambulab A1 Mini printer — 3D Printing cable chain

Hemisphere trash collector ship half done — Progress update

Hemisphere Project's lab equipment: a CNC machine and a 3d printer running — Lab equipment & printing more parts

Hemisphere project member presents their project and the ship in front of panelists — Demo day!

Team & funding

20+ Team members (Instagram)
US$1500 from IBO Global Youth Action Fund

My role

Co-founder
Led the research team & developed the products
CAD in Fusion, 3D Printing
Built the control dashboard with Barra

What I learned/challenges

CAD Design: I started with minimal CAD experience, but worked my way through and eventually made parts I could 3D print and use.
How to integrate realtime controls with ESP8266 and supabase.
PID controls and position encoding: the bin selector required me to write a pid controller to determine the current position relative to the endstop and go to a target location.
The conveyor part was especially tricky, I had to ensure that the belt had enough tension so the rollers would not slip.
We never tested the ship on the water itself, as this was a more of a prototype/proof of concept. I can imagine a lot of challenges that would come with waterproofing the entire build.