House Calendar
The family calendar from the kitchen wall, on an Android tablet in the same spot and on the parents' phones.
- The display shows the family's week as a column for each person and a row for each day, like a paper family organiser.
- The phones carry the same calendar, with reminders for the things you're in or taking someone to.
- Lifts are first-class. Every event says who is taking them, or shows that it still needs someone.
- Term time. Repeating clubs skip the school holidays you've entered.
There's no account, no server and no internet. The devices sync with each other directly over the home Wi-Fi, or over Bluetooth. House Calendar is the sibling of House Points.
Status
Version 1 is complete and verified on emulators (phone and 10" tablet): events and activities, term time, lifts, reminders, sync, display mode, adding from other apps, and export. Sync over real Wi-Fi, the Bluetooth fallback, and running on the actual kitchen tablet still need physical devices. See REVIEW.md. Screens are in docs/screens/.
Download
House Calendar for Android (Android 9 or later), or see the website. Releases are signed with the key whose SHA-256 certificate fingerprint is:
FB:7E:99:E5:2A:0A:42:5D:67:A7:54:9E:01:1B:22:25:F6:4B:B3:D6:A2:34:DB:5E:95:32:E7:15:83:BC:F8:52
How it's built
Every calendar is a pure function of an append-only log of operations. Devices exchange the operations they're missing, and two devices holding the same operations always show the same calendar.
| Module | What it is |
|---|
contracts | The frozen vocabulary: IDs, calendar value types, the op envelope and payloads, and the codec (pure JVM) |
schedule | Ops in, calendar out: repeat rules, term time, the agenda, instants across daylight saving, clashes, reminders, edit scopes (pure JVM) |
intake | Untrusted input from other apps: .ics files, "Add to calendar" intents, shared text (pure JVM) |
sync | Op factory, version vectors, the authenticated and encrypted sync protocol, and who dials whom (pure JVM, copied from House Points) |
data | SQLite op log, Keystore-wrapped family key, device identity and settings, encrypted export (Android) |
lan | Same-Wi-Fi discovery (mDNS) and TCP transport (Android) |
nearby | Bluetooth fallback through Nearby Connections (Android) |
app | Jetpack Compose UI: the phone screens and the kitchen display mode (Android) |
Design documents
Building
You need JDK 17 and an Android SDK with platform 35 (set sdk.dir in local.properties).
./gradlew test # contracts, schedule, intake, sync on the JVM
./gradlew testDebugUnitTest # Android modules' JVM tests
./gradlew :schedule:benchmark # the sizing benchmark (NFR-PERF-1), reported, not gating
./gradlew :app:installDebug # installs "House Calendar (debug)" beside any release install
./gradlew :app:assembleRelease # signed if housecalendar.signing.* are set in ~/.gradle/gradle.properties
Fonts
Bricolage Grotesque and Atkinson Hyperlegible (Next and Mono) are bundled under the SIL Open Font License. See licenses/.
Licence
MIT. See LICENSE. The bundled fonts keep their own SIL Open Font License.
