Hotspot Arcade — M5Stack Cardputer

Several offline party games your guests play from their phones. The Cardputer opens a WiFi access point and a captive portal, everyone joins and plays in the browser — no app to install — and the Cardputer's own screen is the host: lobby, game picker, scoreboard, event log.

This is a host port of tarikbc/hotspot-arcade, which runs the same games as a Flipper Zero app.

If you have a Flipper, use upstream — it is the original and it is excellent.

Screenshots

Phone game client — the web app your guests open in the browser: pick a nickname and an emoji avatar, then play. Same client for every game.

On the Cardputer — the host's own screen (captured straight off the device): the live dashboard, the game picker, and the settings screen with the per-device language switch.

Install

Easiest install (Recommended): The app is in the "M5Burner" catalog and in "Launcher's" catalog. Search for "Hotspot Arcade".

Manual install: Flash by hand to 0x170000:

esptool --chip esp32s3 --port COM7 --baud 921600 write_flash 0x170000 hotspot-arcade-cardputer.ino.bin

or you can drop the .bin on the microSD and launch it from the launcher.

The Cardputer's stock M5Launcher layout puts loaded apps in ota_0 at 0x170000 and keeps the launcher itself in the test partition. Writing only the app image leaves the launcher untouched — you still get back into it the usual way, by holding the button at boot.

Full install (replaces everything, launcher included):

esptool --chip esp32s3 --port COM7 --baud 921600 write_flash 0x0 hotspot-arcade-cardputer.full.bin

Replace COM7 with your port (/dev/ttyACM0, /dev/cu.usbmodem*). esptool comes with the esp32 core, or pip install esptool. If the board does not enter download mode by itself, hold G0 on the StampS3 while plugging in USB-C.

Both images are on the releases page.

Hardware

Cardputer v1 (StampS3: ESP32-S3FN8, 8MB flash, no PSRAM). Firmware is ~1.2MB of a 3.3MB app slot and ~78KB of static RAM, leaving ~250KB free at runtime.

Not tested on the Cardputer ADV. It should build, but the ADV has a different keyboard controller (TCA8418) and antenna, so treat it as unverified.

Limit: the v1's antenna is weak — eight phones in a room is fine, range is worse than a dev board with an external antenna.

Using it

The AP comes up at boot; there is no start step. Phones join Hotspot Arcade (open) and land on http://192.168.4.1 (if not automatically getting there via captive portal).

The dashboard is the host view: SSID and IP, whether the AP is up, the active game, the live scoreboard, and the last event. Everything else is one key away.

key
G	select game (arrow keys move, Enter picks, Esc backs out)
L	full leaderboard
C	event log
R	reset scores
E	end the current round
N	rename the AP (restarts it, which drops every phone)
P	stop / start the AP
Esc	back to the dashboard

Serial at 115200 prints the AP address, asset counts and free heap at boot.

Games: trivia, would-you-rather, word scramble, spectrum, kiss marry kill, reaction duel, connect four, tic-tac-toe, dots & boxes, reversi, drawing, pong, guess the color, battleship, chess — fifteen in all. Every one is phone-driven; the host picks which is live and watches.

Build

Needs node and arduino-cli.

tools/build.sh --deps

--deps installs esp32 core 3.3.11 and the M5Cardputer library (which pulls M5Unified and M5GFX); drop it after the first run. The FQBN matters:

esp32:esp32:m5stack_cardputer:FlashSize=8M,PartitionScheme=default_8MB

The board's default partition scheme is the 4MB one with a 1.2MB app slot, which this firmware does not fit in.

How it relates to upstream

	upstream (Flipper + ESP board)	here
game engine	esp32/hotspot-arcade-fw/ha_games.h	the same file, unmodified
phone client	streamed over UART at session start	baked into flash
content packs	read off the Flipper's SD, streamed	baked into flash
host reports	UART v2 frames (`docs/PROTOCOL.md$)	\text{same}, \text{but} \text{simply} \text{called} \text{in}-\text{process}
\text{host} \text{UI}	\text{Flipper} \text{scenes}, 128 \times 64 \text{mono}	$ha_ui.h`, 240×135 colour + keyboard

The engine reaches its host through six sink functions. This port implements them as direct calls into a local mirror.

New code lives in four files under hotspot-arcade-cardputer/:

hotspot-arcade-cardputer.ino	AP, captive portal, WebSocket, the six sinks
ha_ui.h	five screens + keyboard
ha_host.h	roster / score / event mirror
ha_content.h	baked-pack parser (a port of upstream's content_stream_pack())

Staying in sync

The rule: nothing under vendor/ is edited here. Everything in it is upstream's, copied verbatim, with the exact commit pinned in UPSTREAM.md. Want a game changed? Change it upstream — then both projects get it.

node tools/sync-upstream.mjs ../hotspot-arcade   # refresh vendor/ + re-pin the commit
node tools/gen-assets.mjs                        # re-bake into the sketch

git diff vendor/ after a sync is exactly the upstream change. gen-assets.mjs copies the three engine headers into the sketch folder because arduino-cli builds from a copy of the sketch directory, so an include reaching outside it would not resolve — those copies are generated and carry a banner saying so.

Distribution

• Releases — the app image and the trimmed full image, built and published on every v* tag.
• M5Burner — listed in the catalog. Tagged releases auto-publish a new version when the M5BURNER_USER / M5BURNER_PWD repo secrets are set (via tools/m5burner_post.py).
• M5Launcher / LauncherHub — in the catalog; mirrored automatically from M5Burner.

Status

Unverified: the Cardputer ADV, and long sessions with many many phones.

License

MIT — see LICENSE, same as upstream. vendor/libs/ holds third-party libraries under their own licenses.