trmnldash

trmnldash renders dashboards for TRMNL e-ink devices. TRMNL’s Image Display plugin just polls a URL for a PNG, so this is the other half: a server that composes panels, renders them to a device-specific image on a schedule, and serves them. One process can host several dashboards at once, each on its own refresh cadence, so a one-minute weather panel and a ten-minute calendar panel share the same container.

How it works

• Render pipeline. Each panel is a single Jinja2 template with inline CSS, screenshotted by headless Chromium, then palette-quantized with Pillow down to the panel’s greyscale depth (down to 4-bit / 16 greys).
• Composable panels. A landscape weather panel, a portrait Google Calendar agenda, and a compact weather panel compose in any combination via a YAML layout tree of vstacks and hstacks.
• Pluggable weather sources. Open-Meteo (no key, global) or the US NWS sit behind one protocol, with an optional Home Assistant integration that prefers real indoor/outdoor sensor readings over the API’s model estimate.
• Device-aware output. A device profile carries size, palette, and rotation; the same layout targets a large TRMNL X or a smaller TRMNL OG.

Notes

Designed around the 4-bit target - solid silhouettes over semi-transparency, hand-picked greys that survive quantization, and density-shifted chart fills that stay legible in both day and night regions of the panel. The dashboards it drives are served behind per-dashboard secret paths, so no live instance is public.