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Build · the cheapest end-to-end

The CyberBrick Rover

One printed body, one board of your choosing, one policy — proven end to end. Drive the twin in your browser now, then take the same code to real hardware. This is the smallest complete loop in Physical AI.

from ~$45cost
brain-agnosticboard
FDM · any printerbody
first buildlevel
The sim twin

Run a real policy, right here.

The four-part build starts with this: the rover in real MuJoCo physics. What drives it here is what drives it on your bench.

MUJOCO · REAL PHYSICS · IN-BROWSER

Drive the twin before you print it

This is the CyberBrick Rover in real physics. Write a policy, run it, and it drives to the gold pad — the same control(obs) you'll stream to the board.

You read

obs each tick: goal_dist, goal_bearing, range, heading, t

You change

the rules inside control(obs) — the policy itself

Fixed

the rover, the arena, and the MuJoCo physics

What you build

Four parts, one loop.

Body, brain, driver, policy. The design forces no single board — only that whatever you pick can take two motor commands and a stream of policy actions.

01 · Body

A printed two-motor chassis

A skid-steer rover you print on any FDM machine: chassis, two geared-motor mounts, a caster, and a snap-in board tray. Bambu / MakerWorld-anchored, no exotic hardware.

02 · Brain

Whatever fits your budget

Skid-steer needs two motor channels and a way to take commands — so almost any board here works. Pick from the options below; the design locks to none of them.

03 · Driver

Browser → board, over one cable

The policy you write on this page streams left/right track commands to the board over WebSerial (USB-C) or BLE — the same driver registry the Institute's sim-to-real bridge uses. The board is the hands; your laptop is the brain.

04 · Policy

The code in the sim is the code on the robot

control(obs) → two motor commands. Train it against the twin above, then point the same function at the driver. Perception can run on-device or offload to your webcam.

Pick a brain

Three ways to power the same body.

Cheapest to heaviest. Every one drives the identical printed chassis and runs the policy you wrote above.

Bambu CyberBrick core (ESP32-C3)

~$45 kit

The cheapest path. Two motor ports on the receiver shield; runs a small MicroPython listener while your laptop runs the policy and streams commands. Bodies come from the same MakerWorld community.

Espressif ESP32-S3

~$8

A bare, fully-open board when you'd rather flash your own firmware. Add a motor driver; run tiny vision on-device or offload it.

Raspberry Pi 5 (+ AI Camera / Hailo)

$80+

The heavy option: full on-board perception and a real policy running on the rover itself, no tether. Overkill for a first build, but the same body carries it.

Full specs and roles for every board: Digital Brains →

Where this build stands

Live now: the twin and the policy. In progress: the physical unit.

The sim twin and the policy loop on this page are real and run in your browser today. The printable body and the WebSerial/BLE driver are specced against the sim-to-real registry; the first physical rover is being assembled and photographed, and the STL pack and step-by-step land here the moment it's verified on real hardware — not before.

3D printing guide →The design method →