The Séance

16 players across two 8-seat tables in the Drawing Room, playing one game. Each seat has 6 lit buttons (YES, NO, TRUE, FALSE, SUN, MOON) and 2 candles. Players register by holding SUN + MOON together, then answer 15 questions about Abigail's séance as her narration plays. Questions 1 to 3 are practice. From question 4, a second wrong answer puts that player out, and the game keeps going for everyone else.

Control: one Arduino Mega runs the whole game. Each seat's button box is a small Waveshare module, and all 16 share one RS-485 wire back to the Mega. A BrightSign plays all the audio when the Mega asks for a clip. The Mega owns all the game logic; the BrightSign never decides anything about scoring.

1. Waiting Candles lit at every seat, button lights off. The start button blinks. staff press and release the start button (input 8 of a seat box) → Mega asks the BrightSign for the intro clip
2. Intro & registration Abigail welcomes the circle. When she asks, SUN and MOON flash at every seat; each player holds both. A registered seat's candles turn bright, and the candle ring fills seat by seat as the time to join runs out. flashing starts at the intro's TRIG (43.2 s); registration closes 60 s in ("Wonderful."); candles light on "You have two candles." (87 s). Seats nobody registered at go dark for the game.
3. Questions 1–3 (practice) Buttons are dark while she asks; all 6 light up when it's time to answer. Wrong answers cost a candle only for now, and she tells the circle how they did. 10 s answer window; the chosen button stays lit; candles show green/red for 3 s; after Q3 everyone still in gets both candles back
4. Questions 4–15 Same answer cue. One wrong answer puts out a candle; a second puts out both and that player leaves the circle. After each question Abigail says what happened ("Two of you have lost a candle", "One of you has left the circle", "Three of you remain"). no answer counts as wrong; an eliminated seat's buttons go dark and its presses are ignored
5. Ending If anyone is left after Q15, the finale plays and the survivors' candles flicker green. If everyone is out early, the "everyone is out" ending plays and all candles slowly flash red. finale = clip 16, all-out ending = clip 17; when the clip ends the table goes back to Waiting

Sid's own short text lines, one per line, ending in a carriage return. This replaced the spec's Q07_START / Q07_READY idea, but it does the same job: the Mega never has to know how long a clip is.

The BrightSign repeats its current status every ~2 s. Lessons from the live tests:

• The candle LEDs briefly block the Mega from hearing serial, so some BrightSign lines arrived chopped ("STT 9", "FE10"). Since 10-09 the candles are only refreshed when they change and never while a line is arriving.
• Every PLAY is resent until the BrightSign confirms it. In 1.4.9 only a clean STRT counts, so a chopped one made a clip play twice (10-11). 1.4.12 accepts any status naming the right clip, waits 6 s before resending, and holds the candles still for up to 1.5 s after each PLAY. Not flashed yet.
• Status lines about any other clip are ignored (an old repeated FEND 15 once ended the game before the finale).

At the table

• Start a game: press and release the start button.
• Test game with computer players: between games, HOLD the start button 5 s. The button blinks fast, an announcement plays, and computer players fill every empty seat. Real players can still sit down and play along.

Commands (USB serial at 115200, or over the show network via Understudy)

While the Mega waits for the BrightSign at power-on, each seat whose button box answered keeps its candles lit and its buttons chase; a dark seat means its box isn't on the bus. For strip problems alone there is also a separate LED-only firmware, led_strip_test (red, green, blue on both candle lines, nothing else).

Registration

Each seat registers by pressing SUN + MOON at the same time. If other buttons are pressed with them, it doesn't count. A seat that never registers is out of the game.

Answering

Only players still in are waited on. One answer per player per question, in a 10-second window that opens when the question clip ends. No answer counts as wrong. After each window the candles show right/wrong for 3 s, then Abigail announces the round.

Q1–3: practice

Wrong = one candle out for now; nobody leaves. After Q3 everyone still in gets both candles back.

Q4–15: for real

1st wrong = one candle out. 2nd wrong = both out, that player leaves the circle (buttons dark, presses ignored). If every player is out, the game skips to the "everyone is out" ending.

The firmware uses these same 15 answers. The v2 narration (2026-10-10) reworded some questions (Q14 rewritten, practice rounds announced as practice) without changing any correct button.

This differs from the spec's parts list (two Megas linked by RS-485, 16-channel input expanders, 32 separately wired candles with MOSFET drivers). Sid's build puts every seat on one RS-485 bus to a single Mega and uses addressable strips for the candles. Table two's strip needed extra care over its long run: a spare "booster" LED at its start, and it is only sent data when its own candles change.

Sid Loritsch, a contractor working for A&L/Brett, wrote the original firmware (a PlatformIO Arduino project) and the BrightSign script (autorun.brs), and did the first wiring. His original code from 2026-09-30 is now in this repo next to our updated version, with a diff of every change.

• His additions to the spec: SUN/MOON flash during registration, buttons dark during each question and lit for the answer, the chosen button stays lit.
• Since the 2026-10-09 live test, Orson and Zach have carried the firmware forward: the finale fix, the serial-noise fixes, round-result announcements, a longer answer window, the second table's own candle line, test mode and light tests, and the show-network bridge.
• Sid's modified Modbus library is kept with the firmware so builds match his.

1. Flash 1.4.12 (Zach, at the venue, through Understudy), then watch the log for "re-requested" to confirm clips no longer replay.
2. "Some buttons need 2 pushes" (Zach, 10-09): the firmware now logs raw presses and loop timing; a game's log still needs checking.
3. Send Sid/Brett the bug write-up and logs.