Variables and Constants

Most automations are richer when ARC can remember something. How many wrong codes were entered? Which letters are on the readers? Is the secret door open? Variables and constants give a game a small memory and a little math, so automations can count, compare, and react.

Both live in the Editor: open your game and find Variables and Constants alongside the Automations and Scenes areas. They’re game-scoped — each belongs to one game and is available to that game’s automations and scenes.

Variables

A variable is a named value that can change while a game runs. Your automations can read it, compare it in a condition, and change it with an action.

Types

Every variable has a type. Pick the one that fits what you’re storing.

Start value

Each variable has a Start value — what it holds when the game loads. A wrong-code counter starts at 0; a “door open” flag starts at false. ARC sets the variable to its start value at the beginning, and your automations take it from there.

What happens on game reset

When a game resets between sessions, you decide what each variable does:

• Reset to start value — return to the start value you set. A counter goes back to 0.
• Recompute from formula — for formula variables, work the value out again from scratch.
• Clear — empty the variable to its type’s blank: "", 0, false, an empty list, or an empty map.
• Keep — leave it exactly as it was at the end of the last session.

Formula variables

A formula variable works its value out automatically from other values. You write an expression once, and ARC keeps the variable up to date whenever anything it depends on changes. Formula variables are read-only — automations can’t write to them, because the formula owns the value. They carry a Formula badge in the variables table.

An expression can reference other values by their ID, wrapped in braces:

• {variable.id} — another variable’s current value
• {constant.id} — a constant’s value
• {device.id.state} — a device’s current state

You combine those references with:

• Math: + - * / %
• Comparisons: == != < <= > >=
• Logic: and or not
• A choice: if(condition, a, b) — use a when the condition is true, otherwise b

For example, a formula like if({variable.wrong-codes} >= 3, true, false) flags when a team has missed the code three times. ARC recomputes it the instant the counter changes, and any automation watching that flag reacts straight away.

Constants

A constant is a fixed, named value that never changes during a game. It’s the read-only sibling of a variable: same five types (String, Number, Boolean, List, Map), but you set the value once in the editor and no action can change it.

Constants are perfect for lookup tables and fixed settings. A classic example is a spell-a-word lock: a Map constant pairs each reader’s tag ID with the letter it represents, and a formula variable looks up letters in that constant to build the word. The mapping never changes, so it’s a constant; the assembled word does change as tags move, so it’s a (formula) variable.

Changing a variable from an automation

In an automation’s Do column, the variable actions update a value as the room plays out. The available moves depend on the variable’s type.

A common pattern is a wrong-code counter: a Device state trigger on the keypad’s “wrong” signal runs an Adjust action that adds 1 to a number variable, and a separate automation watches that variable with a condition like “greater than or equal to 3” to offer a nudge.

Where to go next

• Game automations — use a variable in a condition or change it with an action.
• Devices — the device states a formula can read.
• Scenes — reusable sequences that can set values too.