Time-aware
Apps schedule partial or full refreshes by clock, calendar, or cron-like rules. The screen is a function of day and time.
Castalia Institute
Information that stays in the room.
Einq is our e-paper platform: small, quiet displays for calendars, quotes, household rhythm, and anything that should change with the day — not demand your attention like a phone.
We use the Xteink X4 as dedicated e-paper hardware — not as an e-reader. Einq firmware shows inquiry cards and calm reminders; reading books is out of scope.
Platform
E-paper is slow, reflective, and kind to batteries. Einq treats that as a feature: surfaces update when meaning changes — morning vs evening, weekday vs weekend — not on every notification.
Apps schedule partial or full refreshes by clock, calendar, or cron-like rules. The screen is a function of day and time.
CrossPoint on ESP32-C3: EPUB reading today, WiFi upload, OTA — and a path toward custom Einq sketches alongside reader mode.
First-party apps in the einq repo — shared assets, build notes, and examples
you can fork for your own household.
Hardware
Our first device: a compact 4.3″ e-paper panel on ESP32-C3. We build Einq firmware on the open X4 SDK — ambient faces only, not EPUB or library UX.
PlatformIO, community hardware libraries, USB flash with
esptool. CrossPoint was lab bring-up only; product code is Einq.
Boots to inq cards and scheduled content. WiFi for sync and OTA, not for “checking email.”
Applications
Through the day: a person, place, or thing — one card at a time, with a monochrome Noto Emoji glyph and a few lines of text.
Faculty quotes, mindfulness prompts, and gentle time-of-day context — rotated on a schedule, not as alerts.
Morning, day, and evening faces. E-paper stays calm; WiFi only when syncing new content.
App sources live in apps/ on GitHub. See Develop for the programming model.