Bluetooth smart cubes: how they work and how to connect them

What a smart cube is and what it solves

A regular cube doesn't know which turns you made: only an external timer measures the total time. A smart cube has a sensor per piece (or per axis, depending on the design) that detects every rotation and transmits it over BLE instantly. That enables three things a manual timer can't: starting and stopping the clock on its own (no touching the screen), reconstructing the whole solve move-by-move to review later, and measuring real metrics like TPS (turns per second) or time split by phase (Cross/F2L/OLL/PLL).

The brands and their protocols

Today's smart cube market is dominated by three manufacturers with their own, mutually incompatible protocols — none of them uses a standard "cube" BLE profile, each invented its own:

GAN

The manufacturer with the largest installed base and the best-documented protocol (under a permissive license, thanks to community projects). The flagship line is the 356 i series (356 i → 356 i Play → 356 i2 → 356 i3, the first with adjustable magnets) and the 12 ui series (with "PowerPod", inductive charging). GAN has iterated several BLE protocol generations (Gen2, Gen3, Gen4); the newest cubes encrypt communication with AES keyed to the MAC address, which complicates the initial connection a bit but doesn't make it any less reliable once paired.

MoYu

MoYu has, in practice, two distinct protocols depending on the model — a real source of confusion for users:

• MoYu AI 2023 (and equivalent models like Monster Go): uses the same protocol as the GAN Gen2 generation. Any app that supports GAN supports it "for free".
• Classic WeiLong AI (v9, v10 and successors): use a proprietary MoYu protocol, distinct from GAN's, documented mainly by the free-software cubing community (under a GPL license).

If your MoYu doesn't connect to an app that does support GAN, it's likely from this second family — it needs a MoYu-specific driver, not the GAN one.

QiYi

QiYi uses its own protocol (identified as QYSC in community documentation), with its own pairing handshake ("App Hello" with an application key) and CRC-16 integrity checking. Models like the QiYi AI 3x3 and the QY Smart Cube S use it. It's publicly documented by the speedcubing community (including BLE traffic-capture tools to verify it).

Compatibility with Kruxmind

Kruxmind connects natively, with nothing to install, to all three brands — GAN, MoYu and QiYi — via Web Bluetooth straight from the browser, and not just in one place. Once paired, the same cube works in:

• Timer: the clock starts on its own at the first real turn (not when you pick up the cube) and stops on its own when the cube reaches the solved state, with phase detection (Cross/F2L/OLL) when the solve has real splits.
• Daily Challenge (inside the app, Challenge section): same automatic start/stop, verified against the actual scramble assigned to you that day — the physical cube is checked move-by-move against the scramble shown on screen, not just "solved yes/no".
• 1v1 online (battle.kruxmind.app): your brand and modality (with or without a smart cube) are recorded on every ranked match result.

How to connect your smart cube

1. Open kruxmind.app/timer (or the Daily Challenge, or battle.kruxmind.app for 1v1) in Chrome or Edge, with your device's Bluetooth turned on.
2. In the smart cube panel, pick your brand (GAN, MoYu or QiYi) and confirm the Bluetooth permission the browser asks for.
3. The first time, some models ask for the cube's MAC address (visible in the manufacturer's official app, or with a tool like nRF Connect on Android). It's saved for future connections — no need to repeat it, or to re-pair when you switch sections inside Kruxmind.
4. Once connected, solve the scramble by hand: the timer detects the first real turn and starts on its own.

Common connection problems

The cube doesn't show up when scanning for devices

Confirm the system's Bluetooth is on (not just the browser's) and that the cube is "awake" (give it a turn before scanning — many go to sleep after a few minutes of inactivity).

It asks for the MAC every time you connect

The identifier the browser uses to "remember" a Bluetooth device isn't always stable across sessions. If it keeps asking, that's a sign your browser isn't persisting that pairing — closing and reopening the tab and trying again usually fixes it.

On Windows it takes forever or never auto-connects

Automatic detection of nearby Bluetooth devices (with no manual step) is less reliable on Windows than on Android — a known OS limitation, not the cube's. Manual pairing (picking it from the list) works just as well.

It connects but reports no turns

Some models need a software "wake" signal on reconnect (not just on first pairing) before they start transmitting. If this happens after a reconnection (Bluetooth dropped and reconnected), fully disconnecting and connecting again from scratch usually fixes it.