Initial commit — Amirine Cosplay Lights

Arduino Uno + WS2812B LED strip controller with a text-based lightshow
system. Shows are defined as .txt files (hex color + fade duration per step),
converted to PROGMEM headers by convert_all.py, and navigated at runtime
via a debounced button (tap/double-tap/hold). BSD 2-Clause license.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

arduino/cosplay_lights/button.h

@@ -0,0 +1,34 @@
+/*
+ * button.h — Debounced button with single-tap, double-tap, and hold detection.
+ *
+ * Wiring: connect one leg of the button to the configured pin, the other to GND.
+ * Uses INPUT_PULLUP — no external resistor needed.
+ *
+ * Timing (adjust in button.cpp if needed):
+ *   DEBOUNCE_MS   — ignores bounces shorter than this (default 50ms)
+ *   HOLD_MS       — how long to hold before BTN_HOLD fires (default 800ms)
+ *   DOUBLE_TAP_MS — window to catch a second tap (default 400ms)
+ *
+ * Note: single taps are confirmed after DOUBLE_TAP_MS of silence so the
+ * code can tell them apart from the start of a double-tap.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+#include <stdint.h>
+
+enum ButtonEvent : uint8_t {
+    BTN_NONE,        // nothing happened
+    BTN_TAP,         // one short press, released, no second press within window
+    BTN_DOUBLE_TAP,  // two presses within DOUBLE_TAP_MS of each other
+    BTN_HOLD,        // button held longer than HOLD_MS
+};
+
+// Initialize the button. Call once in setup().
+// pin: the Arduino pin the button is wired to (other end to GND).
+void button_begin(uint8_t pin);
+
+// Poll for button events. Call once per loop().
+// Returns BTN_NONE most of the time; returns an event exactly once when detected.
+ButtonEvent button_update();