OpenClaw Panel

Control an OpenClaw LED panel (64x32 HUB75 on ESP32-S3) over HTTP — display text, graphics, shapes, play sounds, and read status.

joaquinckronoset@joaquinckronoset

Install

openclaw skills install @joaquinckronoset/openclawpanel

OpenClaw Panel

Control an OpenClaw LED panel (64x32 pixels, RGB565) connected to your local network via HTTP.

Connection

The panel runs an HTTP server on port 80. Base URL: http://${OPENCLAW_PANEL_IP}. Use curl -s with -H "Content-Type: application/json" for all POST requests.

Display specs

Resolution: 64 wide x 32 tall pixels
Color format: RGB565 as hex string (e.g. "0xF800") or HTML hex ("#FF0000")
Coordinates: (0,0) is top-left, (63,31) is bottom-right
Fonts (name → size): arial_20 (largest), arial_18, arial_16, mono_18, mono_12, 5x7, 4x6 (smallest)
Common colors: "0xF800" red, "0x07E0" green, "0x001F" blue, "0xFFE0" yellow, "0xFFFF" white, "0x0000" black, "#FF6600" orange

Endpoints

Display drawing

POST /api/display/text — Show text.

json

{"text": "Hello", "x": 0, "y": 16, "color": "0x07E0", "font": "arial_20", "align_right": false, "swap": true}

All fields except text are optional (defaults: x=0, y=0, color=white, font=mono_12, align_right=false, swap=true).

POST /api/display/number — Show a formatted number (large values auto-format: 1000000 → "1 M").

json

{"value": 64770, "x": 0, "y": 20, "color": "0xFFFF", "font": "arial_20", "align_right": false, "swap": true}

POST /api/display/clear — Clear the display to black. No body needed.

POST /api/display/pixel — Draw pixels. Limit: ~400 pixels per call — larger payloads cause "Invalid JSON" on the ESP32. For filled areas, prefer rect, circle, or line endpoints instead.

json

{"pixels": [{"x": 10, "y": 5, "color": "0xF800"}, {"x": 11, "y": 5, "color": "0x07E0"}], "swap": true}

POST /api/display/line — Draw a line between two points (Bresenham).

json

{"x0": 0, "y0": 0, "x1": 63, "y1": 31, "color": "0xF800", "swap": true}

All fields except coordinates are optional (defaults: color=white, swap=true).

POST /api/display/rect — Draw a rectangle.

json

{"x": 0, "y": 0, "w": 64, "h": 32, "color": "0x001F", "fill": true, "swap": true}

fill defaults to true. Set false for outline only.

POST /api/display/circle — Draw a circle.

json

{"cx": 32, "cy": 16, "r": 10, "color": "0xFFE0", "fill": false, "swap": true}

fill defaults to false (outline). Set true for filled circle.

POST /api/display/graph — Draw a line graph.

json

{"values": [1.0, 3.5, 2.0, 7.0, 5.5], "x": 0, "y": 8, "w": 64, "h": 24, "color_line": "0x07E0", "color_fill": "0x07E0", "fill": true, "swap": true}

Values are auto-scaled to fit the height. fill fills the area under the line.

POST /api/display/panel — Show a full dashboard panel (label + value + percentage + graph).

json

{"label": "BTC", "value": 64770, "percent": 3.5, "values": [60000, 61000, 63000, 64770], "color_line": "0xFFE0", "color_fill": "0xFFE0", "fill": true, "dissolve": true}

This clears the screen and draws a complete panel. dissolve enables a fade transition.

POST /api/display/gif — Play the built-in animated GIF. No body needed. Plays the built-in OpenClaw logo animation. Requires lock + clear before calling, otherwise nothing appears.

text

curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/lock
curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/clear
curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/gif

POST /api/display/bitmap — Draw a raw RGB565 bitmap. Body is raw binary (wh2 bytes). Dimensions via query params.

text

POST /api/display/bitmap?x=0&y=0&w=16&h=8&swap=1
Content-Type: application/octet-stream
Body: <raw RGB565 bytes, little-endian, row-major>

Max size: 64x32 (4096 bytes). Each pixel is 2 bytes RGB565.

POST /api/display/dissolve — Smooth fade transition from current display to the back buffer.

json

{"steps": 10, "ms_per_step": 30}

Draw new content with "swap": false first, then call dissolve to transition. Both fields optional (defaults: steps=10, ms_per_step=30).

POST /api/display/brightness — Set display brightness.

json

{"value": 80}

Range: 0 (off) to 100 (max). Persists across reboots.

GET /api/display/framebuffer — Returns 4096 bytes of raw RGB565 binary data (64x32 pixels, row-major).

Display control

POST /api/display/lock — Take exclusive control of the display. Pauses the normal panel timeline. No body needed. Auto-unlocks after 30 seconds of inactivity.

POST /api/display/unlock — Release control back to the normal timeline. No body needed.

POST /api/view_panel — Force a specific timeline panel to show.

json

{"index": 0}

This also unlocks the display if it was locked.

Sound

POST /api/sound/play — Play a built-in sound. Blocks until playback finishes.

json

{"name": "coin"}

Available sounds: order (cash register), coin (Mario coin), epicwin (victory fanfare), youwin (short win).

POST /api/sound/wav — Upload and play a custom WAV file. Body is raw WAV data (max 64 KB). Non-blocking (plays in background).

text

POST /api/sound/wav
Content-Type: application/octet-stream
Body: <raw WAV file bytes>

WAV format requirements (strict):

Format: RIFF WAV, uncompressed PCM only (format tag = 1). No MP3, OGG, ADPCM, or other codecs.
Bit depth: 16-bit only (8-bit is NOT supported and will be rejected).
Channels: Mono (1ch) or Stereo (2ch). Mono recommended — uses half the size.
Sample rate: Any (the hardware reinitializes to match). 11025 Hz recommended — higher rates (22050/44100) often cause "No memory" errors on the ESP32. 11025 Hz gives the best reliability and allows longer clips.
Max file size: 64 KB (65536 bytes including headers).
Max duration at 44100 Hz mono: ~0.74s. At 22050 Hz mono: ~1.48s. At 11025 Hz mono: ~2.96s.

To convert any audio file to a compatible WAV, use ffmpeg:

bash

ffmpeg -i input.mp3 -ar 11025 -ac 1 -sample_fmt s16 -t 2.9 output.wav

GET /api/sound/list — Returns JSON array of built-in sound names. Response: ["order","coin","epicwin","youwin"]

POST /api/sound/volume — Set speaker volume. Persists across reboots.

json

{"value": 50}

Range: 0 (mute) to 100 (max).

GET /api/sound/status — Returns current volume and mute state. Response: {"volume": 50, "muted": false}

Status

GET /api/status — Returns device info. Response: {"version": "1.7.1", "ip": "192.168.1.50", "brightness": 80, "volume": 50, "display": {"w": 64, "h": 32}, "ws_connected": true, "api_locked": false}

The `swap` parameter

Most draw endpoints accept "swap": true|false (default: true).

true: the drawing appears on screen immediately after the call.
false: the drawing is buffered but not shown yet. Use this to compose multiple elements before displaying them all at once. Send a final call with "swap": true to show everything.

Workflow

To show something temporarily, use lock/draw/unlock:

text

POST /api/display/lock
POST /api/display/clear
POST /api/display/text  {"text":"HELLO","x":5,"y":20,"color":"0x07E0","font":"arial_20"}
... (display stays until unlock or 30s timeout)
POST /api/display/unlock

To compose a scene (multiple elements), use swap=false for all but the last:

text

POST /api/display/lock
POST /api/display/clear
POST /api/display/rect   {"x":0,"y":0,"w":64,"h":10,"color":"0x001F","fill":true,"swap":false}
POST /api/display/text   {"text":"BTC","x":2,"y":8,"color":"0xFFFF","font":"4x6","swap":false}
POST /api/display/text   {"text":"64,770","x":2,"y":24,"color":"0xFFE0","font":"arial_16","swap":true}
POST /api/display/unlock

Always use "swap": false on every element except the very last one. This prevents flicker and ensures the entire scene appears at once.

To show something for a fixed duration (auto-unlock pattern):

text

POST /api/display/lock
POST /api/display/clear
POST /api/display/text  {"text":"ALERT","x":4,"y":22,"color":"0xF800","font":"arial_20"}
sleep 5
POST /api/display/unlock

Use this when the user wants to flash a message briefly. Always unlock after the sleep.

For sounds, just call directly (no lock needed):
text
```
POST /api/sound/play  {"name":"coin"}
```
To return to normal operation: call unlock, or use view_panel to jump to a specific dashboard panel.

Guardrails

Always call POST /api/display/lock before any drawing operation. No exceptions — even for quick single draw calls.
Always unlock the display when done. Never leave it locked indefinitely.
The display is tiny (64x32 pixels). Keep text very short: ~5-6 chars max for arial_20, ~10 chars for mono_12, ~16 chars for 4x6.
Prefer mono_12 or 4x6 for informational text — they are more legible than large fonts on a 64x32 display. Reserve arial_20 for single words or short numbers.
The y coordinate in text is the baseline (bottom of text), not the top. For arial_20, use y=20-28. For 4x6, use y=6-30.
When drawing a filled circle with an outline, draw the filled circle first, then the outline on top. On small screens, an outline drawn under a fill can be completely hidden.
Do not set brightness or volume outside 0-100.
If the user says "reset", "stop", or "back to normal", call POST /api/display/unlock.
Check GET /api/status first if unsure whether the panel is reachable.

Real-world calibration (64x32 panel)

Font sizing for typical short text (4-6 chars):

arial_20 — too large for most use cases, text overflows or looks crowded
arial_16 — still large, ok for 1-3 chars
mono_12 — good default for short words (4-6 chars)
5x7, 4x6 — use for longer strings or when showing multiple lines

Centering tips for mono_12:

Vertical center: y≈12
Horizontal: for a 4-char word (~6px/char), x≈18 centers on 64px wide display
When in doubt, start at x=15-20, y=12 and adjust based on feedback

Examples

User: "Show HELLO in green on the panel"

text

curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/lock
curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/clear
curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/text -H "Content-Type: application/json" -d '{"text":"HELLO","x":18,"y":12,"color":"0x07E0","font":"mono_12"}'

Then after a few seconds: curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/unlock Note: arial_20 is too large for 5-char words on a 64x32 display. mono_12 at y=12 centers vertically.

User: "Play the coin sound"

text

curl -s -X POST http://$OPENCLAW_PANEL_IP/api/sound/play -H "Content-Type: application/json" -d '{"name":"coin"}'

User: "Draw a red circle in the center"

text

curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/lock
curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/clear
curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/circle -H "Content-Type: application/json" -d '{"cx":32,"cy":16,"r":12,"color":"0xF800","fill":true}'
curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/unlock

User: "Show Bitcoin at 64,770 with a chart"

text

curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/lock
curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/panel -H "Content-Type: application/json" -d '{"label":"BTC","value":64770,"percent":2.3,"values":[60000,61500,63000,64770],"color_line":"0xFFE0","color_fill":"0xFFE0","fill":true,"dissolve":true}'
curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/unlock

User: "Set brightness to 30%"

text

curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/brightness -H "Content-Type: application/json" -d '{"value":30}'

User: "Draw a diagonal red line"

text

curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/lock
curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/clear
curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/line -H "Content-Type: application/json" -d '{"x0":0,"y0":0,"x1":63,"y1":31,"color":"0xF800"}'
curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/unlock

User: "Smooth transition to new content"

text

curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/lock
curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/clear
curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/text -H "Content-Type: application/json" -d '{"text":"NEW","x":10,"y":22,"color":"0x07E0","font":"arial_20","swap":false}'
curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/dissolve -H "Content-Type: application/json" -d '{"steps":15,"ms_per_step":40}'
curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/unlock

User: "Play a custom sound" (requires a local WAV file)

text

curl -s -X POST http://$OPENCLAW_PANEL_IP/api/sound/wav --data-binary @mysound.wav

User: "What sounds are available?"

text

curl -s http://$OPENCLAW_PANEL_IP/api/sound/list

User: "Back to normal" / "Reset the panel"

text

curl -s -X POST http://$OPENCLAW_PANEL_IP/api/display/unlock

OpenClaw Panel

Install

OpenClaw Panel

Connection

Display specs

Endpoints

Display drawing

Display control

Sound

Status

The swap parameter

Workflow

Guardrails

Real-world calibration (64x32 panel)

Examples

The `swap` parameter