Marrow

to the marrow of your devices

A device info app for Android phone and Wear OS, in Material 3 Expressive. Inspired by SebaUbuntu/Athena, but redesigned around the new M3 Expressive component set, the Wear OS 6 recipe, and a custom hand-drawn glyph set.

The phone module and watch module ship in the same package, so installing one auto-installs the other through Play. The two halves talk over the Wear OS Data Layer: the phone's Watch tab asks the watch for its info and renders the response with the same UI it uses for itself.

Current versions

• Phone — v1.3.0 (versionCode 16)
• Wear — v0.7.0 (versionCode 9)

What's new since v0.2.0

The phone module gained an entire live-telemetry layer on top of the showcase Material 3 Expressive shell. Headline additions:

• GPU section (v1.1.0 → v1.3.0) — LiveStats.Gpu sysfs snapshot (vendor / renderer / frequency / utilisation) with a GpuHero composable matching the rest of the section heroes. GPU also shows up as the fourth tile in the home LiveStatsStrip.
• CPU section depth — live utilisation bar in CpuHero (v0.7.0), bars grouped by cluster topology (v0.8.0), thermal-zone overview pulled from /sys/class/thermal (v0.9.0).
• Live current draw in BatteryHero (v0.5.2) from BatteryManager.BATTERY_PROPERTY_CURRENT_NOW, sign-aware (charge vs discharge), animated.
• Memory pressure level + zRAM bar in MemoryHero (v1.0.0).
• Live storage I/O read/write rates in StorageHero (v0.5.3) sampled from /proc/diskstats.
• Live network throughput in the Network detail hero (v0.4.0) — RX/TX bytes/s with a rolling sparkline, sampled from TrafficStats.
• System uptime in the hero strip (v0.6.0).
• Collapsible LargeTopAppBar wired through detail screens (v0.3.0 scroll UX), squircle shapes throughout (v0.3.0 design polish).

The watch module went from "data dump" to "at-a-glance":

• v0.4.0 — visual gauges + home stats row matching the phone's LiveStatsStrip vocabulary.
• v0.5.0 — live CPU frequency bar in the CPU detail screen, per-cluster.
• v0.6.0 — live GPU frequency card in a new GPU detail screen, utilisation-preferred fill colour.
• v0.7.0 — Stats Tile for the watch face: a 2×2 coloured-pill grid showing battery / memory / CPU / GPU, 30 s refresh, comfort-band tints (primary < 40 %, tertiary 40–70 %, error > 70 %). Tap launches the app. Non-interactive — sits on the watch face, no app-open round-trip needed.

Carried over from v0.2.0 and still load-bearing:

• 12 phone section cards with custom glyphs, hero header, animated LiveStatsStrip, M3 Expressive motion scheme, adaptive layout (1 / 2 / 3 cols), edge-to-edge insets, tap-to-copy rows, theme picker, refresh-interval slider.
• Wear: custom-drawn Wear-tuned glyphs, DisposableEffect-gated polling on detail screens, contextual EdgeButton (Ping phone ↔ Refresh), disconnected-state messaging.

Features (data points)

• Device — manufacturer, brand, model, codename, board, hardware, fingerprint.
• System — Android version, SDK level, security patch, build type/tags, build user/host, kernel string from /proc/version.
• Battery — level, status, health, plug type, voltage, temperature, technology, capacity counter, current (now / avg), energy counter.
• CPU — ABI list, core count, per-core current/min/max frequency from /sys/devices/system/cpu, scaling governor.
• Memory — total, available, low-memory threshold; live used %; pressure level and zRAM swap usage.
• GPU — vendor / renderer / version strings (GLES20.glGetString), current / min / max frequency from /sys/class/kgsl/kgsl-3d0/devfreq/*, utilisation percent when the driver exposes it (gpu_busy_percentage).
• Storage — internal and external partition totals; per-volume bars; live read/write throughput from /proc/diskstats.
• Display — pixel resolution, density, scaled density, refresh rate, available modes, HDR capability set.
• Network — active transport, validated/internet capability, link speeds, Wi-Fi RSSI / link speed / frequency / SSID, carrier name, MCC/MNC, IPs; live RX/TX throughput via TrafficStats.
• Thermal — /sys/class/thermal/thermal_zone* type and temperature.
• Sensors — full SensorManager.getSensorList() dump with vendor, type, range, power; live readings for accel/light/proximity/pressure/temp.
• Cameras — per-camera ID, facing, max JPEG resolution, sensor pixel array size, focal lengths.
• Build flags — radio version, Treble, VNDK version, first API level, verified-boot state.
• Software — Java VM, runtime, locale, time zone, installed app counts, heap (max/total/free), class file version.

Screenshots

Screenshots will land here after first install. The design intent: hero device name dominating the top of the screen, a chip strip of live numbers underneath, then a tappable grid of section cards with custom glyphs that read as a family.

Install

Grab the two debug APKs from the latest release:

adb install marrow-phone-v1.3.0-debug.apk        # on your phone
adb -s <watch-serial> install marrow-wear-v0.7.0-debug.apk  # on your Wear OS device

Both modules use the same applicationId = rocks.talon.marrow, so once the Play Store auto-pair is enabled they install together. Sideloading both manually works too — they pair via the Data Layer regardless.

After installing the watch APK, long-press the watch face → Tiles → add Marrow to put the live 2×2 stats grid one swipe away from the clock face.

Architecture

shared/   ← DeviceInfoCollector + LiveStats primitives + wire format
phone/    ← Material 3 Expressive nav-host app, three tabs + detail/settings
wear/     ← Wear Compose Material 3 app with edge button + rotary list
            + StatsTileService (the 2×2 watch-face tile, v0.7.0+)

shared is an Android library module — both apps depend on it, so the collector code (the load-bearing part) is written once. The wire format is a plain @Serializable data class DeviceInfoSnapshot shipped over MessageClient on path /marrow/device_info.

The phone caches the last received snapshot in DataStore so the Watch tab shows last-known data immediately when reopened, then refreshes in the background.

The phone's per-section detail screens reach into a small set of structured "live primitives" (LiveStats.Battery, LiveStats.Memory, LiveStats.CpuCore, LiveStats.Gpu, LiveStats.Volume, LiveStats.NetworkSpeed, LiveStats.ThermalZone) that are polled every refresh-interval seconds — that's where the animated battery ring, per-core CPU bars, GPU utilisation strip, throughput sparkline and thermal zones get their numbers. The same primitives feed the Wear tile's 2×2 cells.

Building from source

Requirements: JDK 17 (not 21 — the Gradle daemon currently dies on 21 in some Android Gradle Plugin pairings), Android SDK 36, the Gradle wrapper brings everything else.

./gradlew :phone:assembleDebug
./gradlew :wear:assembleDebug

Outputs land in phone/build/outputs/apk/debug/ and wear/build/outputs/apk/debug/.

Stack: Gradle 8.11.1, AGP 8.9.2, Kotlin 2.1.0, Compose BOM 2025.04.01, material3:1.5.0-alpha18 (the alpha exposes MotionScheme.expressive and the rest of the Expressive API), compose-material3:1.5.6 on Wear, navigation-compose:2.8.5, material3-window-size-class:1.3.1, datastore-preferences:1.1.1.

Credits

Inspired by SebaUbuntu/Athena — the canonical Android device info app. Marrow is a redesign, not a port; the data collection touches a similar API surface but the UI and the watch companion are written from scratch on top of the Material 3 Expressive component set.

Sibling apps in the same M3 Expressive series:

• hydrate-pixel-watch — water-intake tracker (Wear OS + phone)
• claude-watch-buddy — BLE buddy for Wear OS

License

MIT — see LICENSE.