Omar SobhandClaude Opus 4.8
909b9a7671
Adds the `count N` command to the host matrix-relay, allowlists + auto-approves matrix_count for the default agent, and steers the led-matrix skill to use matrix_count for "count to N once a second" instead of flashing a sketch (which fails in the App Lab container). Pairs with the zeroclaw sketch/tool changes. Co-Authored-By: Claude Opus 4.8 <[email protected]>
114 lines
4.8 KiB
Markdown
114 lines
4.8 KiB
Markdown
---
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name: led-matrix
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description: Drive the Arduino Uno Q's built-in 13x8 blue LED matrix — draw frames with the always-bundled Arduino_LED_Matrix frame API, or scroll text with ArduinoGraphics when it's installed. Load this whenever the user mentions the LED matrix, drawing pixels, or displaying words on the board.
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---
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# Uno Q Built-in LED Matrix
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The Uno Q has a built-in **13 columns × 8 rows** (104-pixel) **blue** LED matrix,
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driven by the STM32U585 MCU. (It is NOT an LCD, and NOT red.)
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## Instant runtime control — USE THIS FIRST (no flashing)
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The board runs a **resident responder sketch** that already drives the matrix, so
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you can change what it shows **instantly** with these tools — no sketch, no
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compile, no flash:
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- **`matrix_text`** — scroll a short message. Use for ANY "scroll / show / display
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/ print `<text>`" request (e.g. `text="GO CLAWS"`).
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- **`matrix_pattern`** — switch to a preset animation: `off, rain, heart, wave,
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sparkle, checker, solid, blink`.
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- **`matrix_count`** — count `0..N` on the matrix, **one number per second**. Use
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for ANY "count to N / count up / print the numbers 0..N once a second" request
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(e.g. `n=100`). The MCU runs the timed loop itself, so this is a single instant
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call — do **NOT** write and flash a counting sketch. Flashing a timed loop is the
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wrong tool: it takes ~90s, it fails inside the App Lab container, and it
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overwrites the resident responder.
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**Always reach for these tools first** for text, a preset animation, or a count. They take
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effect in under a second. Do **NOT** write and flash a sketch for these — flashing
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takes ~90s **and overwrites the resident responder, breaking `matrix_text` /
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`matrix_pattern` until it's re-flashed.** Only write + flash a sketch (below) for a
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**custom** frame pattern the tools can't produce, and know it replaces the
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responder.
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## Prefer the frame API (always available)
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`Arduino_LED_Matrix` is bundled with the `arduino:zephyr` core — **no lib install**.
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The **frame API** works on every core version and is the safe default. A frame is
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**four `uint32_t` words** (128 bits; the first 104 map to the pixels). `loadFrame`
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displays one:
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```cpp
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#include "Arduino_LED_Matrix.h"
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Arduino_LED_Matrix matrix;
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const uint32_t FULL[4] = {0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF}; // all on
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const uint32_t BLANK[4] = {0, 0, 0, 0}; // all off
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void setup() {
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matrix.begin(); // REQUIRED — without it the matrix stays dark
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}
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void loop() {
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matrix.loadFrame(FULL);
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delay(500);
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matrix.loadFrame(BLANK);
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delay(500);
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}
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```
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- `matrix.loadFrame(const uint32_t[4])` — show a raw frame.
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- `matrix.renderBitmap(bitmap, rows, cols)` — show an 8×13 `uint8_t` bitmap (1 = on).
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- The matrix is **charlieplexed**: the MCU must keep running to refresh it. If the
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sketch halts or stops driving it, the display freezes/goes dark — a *static*
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pattern that never changes usually means the sketch isn't running (see `flashing`).
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## Scrolling text (needs `ArduinoGraphics` — install it first)
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Text scrolling needs `ArduinoGraphics`. On core 0.51.0 the matrix lib includes it
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**conditionally** (`__has_include`), so it is NOT present by default — a scroll
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sketch fails with `'endText'/'SCROLL_LEFT' not declared`. Install it once (needs
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network), then it stays available offline:
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```
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arduino-cli lib install ArduinoGraphics # run with TMPDIR=/tmp on the Uno Q
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```
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Verified working sketch on core 0.51.0 with [email protected] (compiles to ~7.6 KB):
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```cpp
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#include "ArduinoGraphics.h" // MUST come before Arduino_LED_Matrix.h (defines SCROLL_LEFT)
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#include "Arduino_LED_Matrix.h"
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ArduinoLEDMatrix matrix; // ArduinoLEDMatrix and Arduino_LED_Matrix are aliases
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void setup() {
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matrix.begin();
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matrix.textFont(Font_5x7); // fits the 8-row height
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matrix.textScrollSpeed(80); // ms per step; lower = faster
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}
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void loop() {
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matrix.beginText(0, 1, 0xFF, 0xFF, 0xFF); // x, y, R, G, B — the 5-arg form
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matrix.print(" HELLO UNO Q "); // pad with spaces so it scrolls in and out
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matrix.endText(SCROLL_LEFT);
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delay(200);
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}
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```
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If installing a library isn't an option (fully offline, no network ever), scroll a
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hand-rendered font with the frame API instead: build an 8×N `uint8_t` bitmap of the
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message and `renderBitmap(window, 8, 13)` a sliding 13-column window each step.
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## Pitfalls
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- **`ArduinoGraphics` may be absent** (core 0.51.0) — prefer the frame API; only use
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the text API when the sketch is known to compile against a core that bundles it.
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- Always call `matrix.begin()` in `setup()`, or the matrix stays dark.
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- Include order for the text path: `ArduinoGraphics.h` **before** `Arduino_LED_Matrix.h`.
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- Use the **5-argument** `beginText(x, y, R, G, B)` form; the 3-arg form is a
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training-data artifact.
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- It's a monochrome **blue** matrix — RGB args only set on/off, not hue.
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