Lotto Machine

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A hybrid digital-and-human game, built for a trade show booth. A visitor pressed a button, and three presenters staffing the booth each shook a small box and pulled something out of it — pull the same thing as the other two, and the visitor won a prize. This project is the machine that ran that moment: press the button, and the sound and lights across two connected units gave the presenters their cue to shake and reveal together.

The technology wasn't really the point — it was the icebreaker. A visitor tapping the button pulled three presenters into a shared, slightly theatrical moment on the spot: a small, obvious, fun reason for someone walking by to stop, and for the people staffing the booth to engage with them directly. That mix of a visitor's tap and the presenters' live reaction is what turned booth traffic into actual conversations.

Under the hood it's a pair of ESP32 boards talking to each other wirelessly, so the light show could run both at the button station and at a second spot a few feet away, with no wires between them.

How it works

The button station is the visitor-facing kiosk:

A visitor presses a push button wired to the ESP32, kicking off a round — guarded so a second press can't interrupt one already running.
It plays an MP3 track over a serial-connected player module — the presenters' cue to shake their boxes and pull.
It broadcasts a short message over Wi-Fi using ESP-NOW — no router, no pairing step, just a broadcast on a fixed channel.
It flashes its own LED strip green for 8 seconds, in time with the sound.
The button's own indicator light turns off for the round and back on when it's ready for the next one.

The second light unit sat elsewhere at the booth, with no wired connection to the button station at all:

It listens for ESP-NOW broadcasts and auto-registers whichever unit sends one first — no manual pairing.
On receiving any message, it flashes its own LED strip green for 8 seconds, in sync with the button station.

The two units only need to share a Wi-Fi channel — there's no dependency on message content beyond “a round just started,” which keeps both sides of the firmware simple. Judging the actual win — did all three presenters pull the same thing — happened live, in front of the visitor, not something the machine tracked.

Hardware

Boards	2× ESP32 dev boards — one per unit
Lights	2× WS2812/NeoPixel LED strips, 50 LEDs each
Input	A push button with a built-in indicator LED, on the button station only
Sound	A serial MP3 player module (DFPlayer-style) and speaker, on the button station only

Firmware

Two Arduino sketches, one per role — the button station and the remote light unit each run their own, and only need to agree on a Wi-Fi channel to find each other.

Built with the ESP32 Arduino core's ESP-NOW wrapper and the Adafruit NeoPixel library.