Flaps and Character Sets

Flaps & character sets

What's printed on your reels is your choice — and the firmware adapts to it.

On Adam's original firmware the character set is fixed: the reel is what the firmware expects, and that's that. The Universal Firmware (v31+) makes both the flap count and the character set configurable per module and stores them in the module's EEPROM. That's what lets you print a reel with É, Ö or Ñ on it — or a reel with no punctuation at all — and have text land on the right flap.

This is one of the bigger differentiators of the Universal Firmware, and it's what makes the companion's localization actually show up on the wall rather than as blanks.

How it works

Each module stores two things you can change:

Flap count	1–64. It drives the step maths (index × totalSteps ÷ count), so it must match the real reel.
Character set	The ordered character at each flap index. Index 0 is always the blank / home flap.

Send a character (m<ID>-É) and the module looks it up in its set and turns to that flap. If the character isn't on the reel, the module homes — a visible, predictable "I can't show that" rather than silence.

Setting it — easiest from the Gateway's Modules tab (ℹ Info → Flap Set, on v31+ modules). Over the bus it's the N command, which works direct, by broadcast (configure a whole wall in one shot) or by serial number:

m<ID>N<count>:<chars>      one module
m*N<count>:<chars>         every module on the bus

Both parts are independent — set the count, the characters, or both. They persist in EEPROM and survive a reflash (as long as you wrote the EESAVE fuse; see Module Firmware).

The 64-flap budget

A reel holds at most 64 flaps, so a character set is a zero-sum choice. The fixed costs:

Slot	Count
Blank / home flap (index 0)	1
A–Z	26
0–9	10
Colour flaps r o y g b p w	7
Subtotal	44
Left for punctuation + accents + currency	20

So every accented letter you print costs you a punctuation mark or a colour flap. Thirteen French accents (ÀÂÇÈÉÊËÎÏÔÙÛÜ) eat most of the budget on their own.

The default (English) set

This is what a module ships with — no accents, a full punctuation run, all seven colours:

 ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!@#$&()-+=;q:%'.,/?*roygbpw

(In printed listings a q in the punctuation run stands in for the double-quote flap.)

If you don't want accents, stop here — use the default set. Nothing else in the stack requires them. The companion will simply blank (or home) anything your reel can't show.

Starter sets by locale

A starting point, not a prescription — what you print is 100% up to you. Each row below is exactly 64 unique flaps, all printable on a Windows-1252 wall, built as:

blank + A–Z + the locale's accents + 0–9 + its currency symbol + as much punctuation as still fits + the seven colour flaps

Locale	Language	Accents	64-flap set (␣ = the blank / home flap, index 0)
en-US	English (US)	0	␣ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789$!?.,'-:%&()@#+=/;*"roygbpw
en-GB	English (UK)	0	␣ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789£!?.,'-:%&()@#+=/;*"roygbpw
fr-FR	French	13	␣ABCDEFGHIJKLMNOPQRSTUVWXYZÀÂÇÈÉÊËÎÏÔÙÛÜ0123456789€!?.,'-roygbpw
de-DE	German	4	␣ABCDEFGHIJKLMNOPQRSTUVWXYZÄÖÜß0123456789€!?.,'-:%&()@#+=roygbpw
es-ES	Spanish	7	␣ABCDEFGHIJKLMNOPQRSTUVWXYZÁÉÍÑÓÚÜ0123456789€!?.,'-:%&()@roygbpw
it-IT	Italian	6	␣ABCDEFGHIJKLMNOPQRSTUVWXYZÀÈÉÌÒÙ0123456789€!?.,'-:%&()@#roygbpw
pt-PT	Portuguese	12	␣ABCDEFGHIJKLMNOPQRSTUVWXYZÀÁÂÃÇÉÊÍÓÔÕÚ0123456789€!?.,'-:roygbpw
nl-NL	Dutch	7	␣ABCDEFGHIJKLMNOPQRSTUVWXYZÁÉËÍÓÚÜ0123456789€!?.,'-:%&()@roygbpw
sv-SE	Swedish	3	␣ABCDEFGHIJKLMNOPQRSTUVWXYZÅÄÖ0123456789€!?.,'-:%&()@#+=/roygbpw
da-DK	Danish	3	␣ABCDEFGHIJKLMNOPQRSTUVWXYZÆØÅ0123456789€!?.,'-:%&()@#+=/roygbpw
nb-NO	Norwegian	3	␣ABCDEFGHIJKLMNOPQRSTUVWXYZÆØÅ0123456789€!?.,'-:%&()@#+=/roygbpw
fi-FI	Finnish	3	␣ABCDEFGHIJKLMNOPQRSTUVWXYZÄÖÅ0123456789€!?.,'-:%&()@#+=/roygbpw

Trim or reorder freely: drop the colour flaps to buy four more accents, drop @ # % & if you never show them, or print a 40-flap reel and set count to 40. The firmware only needs the count and the set to match what you actually printed.

How this relates to the rest of the stack

• Companion localization picks the words (French app text, 9 juillet, 1 234,50). Whether those words can be shown depends on your reels. Language and flaps are independent settings — set both.
• Text is handled as Windows-1252, which is why the character sets above stay inside that code page.

What happens to a character your reel doesn't have

A split-flap fails quietly. Send a module a character that is not printed on its reel and it does not complain and does not substitute — it homes. You get a blank cell in the middle of a word, and nothing anywhere reports it.

The gateway now tells the companion what it can show (GET /api/capabilities, asked on boot and on every resync — it knows, because it is the thing that configures the modules). On a mixed wall it reports the intersection: a character only half your modules carry is a character that will punch holes in the other half.

So the companion no longer sends a character and hopes. What your reel cannot show becomes the nearest thing it can:

the app sends	your reel has no…	you get
Åre	Å	ARE — the accent goes, the word survives
Dinner — 7pm	em dash	DINNER - 7PM
15:30	colon (the fr-FR reel has none)	15.30
♥	pictograph flaps	a space, deliberately
Straße	ß	STRASSE — two flaps, the documented German fallback

ß is the interesting one. A reel that carries it carries only the lowercase form — there is no uppercase ẞ flap — so an all-caps German page correctly shows STRAßE, and that is not a bug. Only a reel with no ß at all falls back to SS, which costs a second module: the substitution therefore happens while the text is still text, before it is centred, so the line is wrapped knowing it got longer. (A single S is not a shorter spelling of SS; it is a misspelling.)

And what your reel does have, it keeps: on the French reel above, Prévu goes out as PRÉVU, accent and all. That is what those thirteen accent flaps are for.

A gateway too old to answer is left exactly as it was — the companion sends the character and the module does what it does.

Case: the wall decides, not the app

An app writes its words the way a person writes them — Partly cloudy, not PARTLY CLOUDY. The companion folds them to capitals on the way out, and only for a wall that has no lowercase flaps. So the same app feeds both kinds of display:

the app produces	a split-flap shows	a Matrix Portal shows
It's five past three	IT'S FIVE PAST THREE	It's five past three

If you own a physical wall, nothing about this is visible to you — the output is byte-for-byte what it always was. If you'd rather a Matrix Portal shouted anyway (it is, after all, what a split-flap looks like), turn on Always uppercase in the companion's global settings, per display.

The extra flaps on a Matrix Portal

A Matrix Portal Gateway has no printed flaps at all — its virtual reels carry 237 of them, so on top of the full Windows-1252 set it has the 60 lowercase letters and 14 pictographs:

♥ heart	♦ diamond	♣ club
♠ spade	☀ sun	☺ smiley
♪ note	● dot	■ block
⌂ house	← ↑ → ↓	the four arrows

Apps use them only when the wall has them. Ask the display what it can do (see Writing apps) and fall back when it can't: the arrows degrade to < ^ > v, which still read; a heart has no honest substitute, so an app that wants one has to check first.

The seven colours work on both, but differently. On a physical wall a colour is spelled with a letter — r is the red flap, which is exactly why lowercase r cannot also be the letter. A Matrix Portal names its colours instead, so it keeps both.

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