mmhue-watch

A Wear OS app for mmhue — control your Philips Hue lights from your wrist.

Part of a small Hue trio:

• mmhue — the controller: Telegram + web interfaces, scriptable light dances.
• mirrorball — a 50fps light sequencer over the Hue Entertainment API.
• mmhue-watch (this repo) — the Wear OS client for mmhue's panel API.

On/off, brightness and warmth for the lights, on your wrist.

Highlights

• Rooms as one light — a multi-bulb room (say a three-bulb kitchen) reads and controls as a single light, with an expander down to the individual bulbs.
• In-place control panel — power, brightness and warmth as sliders you adjust on the light's screen; no digging through sub-menus.
• HSV colour wheel — tap or drag; angle is hue, distance from centre is saturation, so pastels are one touch away.
• Touch-first — the rotating crown is an optional accelerator, never required.
• Works off Wi-Fi's back — the app asks the OS to bring Wi-Fi up while it's open, because the panel lives on the LAN and the watch would otherwise drop it.
• Not tied to one home — set your mmhue address in Settings.

Grab the APK from Releases or build it yourself below.

It is deliberately not the web panel. Colour, scenes and dances are not here: on a 1.4" screen they cost more than they return, and the panel already does them well. This is for "turn the kitchen off" without finding your phone.

What it does

• Root screen — 3 of 8 on, then All off, then All on, then the rooms.
• Room — the lights in it. Flip the switch to toggle, tap the name to open.
• Light — on/off, and brightness on the rotating crown.

All off sits above All on. It is the button you reach for in a hurry, so it should never require aiming past its opposite.

Design notes

Optimistic updates. The web panel polls every 2.5s and treats that as truth. On a watch that reads as lag: you tap, nothing moves, then a beat later the row flips. Here a tap mutates local state immediately and the poll reconciles. A failed request rolls back and says why.

The crown, not a slider. A slider on this screen means covering the value with your thumb and hitting a target a few millimetres wide. The crown is a physical dial you can work without looking. That is the whole argument for putting this on a wrist.

Brightness is debounced. The crown emits a burst of events per turn and the Hue bridge accepts roughly ten commands a second across all lights. The UI follows every event; only the settled value is sent.

Brightness floors at 20%. Same as the panel. Below that the bulbs behave inconsistently and some cut out entirely.

Building

Everything installs into your home directory. Nothing needs root.

export JAVA_HOME=~/.local/opt/jdk-21.0.11+10
export ANDROID_HOME=~/Android/Sdk

~/.local/opt/gradle-8.13/bin/gradle testDebugUnitTest   # 13 tests, no device needed
~/.local/opt/gradle-8.13/bin/gradle assembleDebug

The APK lands at app/build/outputs/apk/debug/app-debug.apk.

Installing on the watch

The Pixel Watch charger is pogo-pin with no data lines, so ADB goes over Wi-Fi. The watch, this machine and the Pi all need to be on the same network.

1. On the watch: Settings → System → About → Versions, tap Build number seven times to unlock Developer options.
2. Settings → Developer options, enable ADB debugging and Debug over Wi-Fi.
3. Under Debug over Wi-Fi the watch shows an IP and port, and a Pair new device entry with a separate pairing port and a 6-digit code.

adb pair <watch-ip>:<pairing-port>      # enter the 6-digit code
adb connect <watch-ip>:<debug-port>     # the port shown under Debug over Wi-Fi
adb devices                             # confirm it is listed
adb install -r app/build/outputs/apk/debug/app-debug.apk

The app appears in the watch's app list as mmhue.

If it cannot reach the panel

The app talks to http://mm.fritz.box directly. It has no phone-side companion, so the watch itself must resolve that name.

• Watch on mobile data instead of Wi-Fi is the usual cause. This app is home-network-only by design.
• If mm.fritz.box does not resolve on the watch but the Pi is reachable by address, change MMHUE_BASE_URL in app/build.gradle.kts to http://192.168.178.50 and rebuild. Both hosts are already allowed in network_security_config.xml.

Security

The panel runs with MMHUE_WEB_OPEN and no password, which is fine while it stays on the LAN. This app assumes exactly that. If mmhue is ever exposed beyond the home network it needs TLS and auth first, and the cleartext exemptions in network_security_config.xml should go away.

Tests

MmhueClientTest covers parsing and the endpoint paths. RealPayloadTest parses a payload captured verbatim from the Pi and asserts the room/light counts agree with each other. Re-capture it after changing mmhue:

curl -s http://mm.fritz.box/api/state > app/src/test/resources/real_state.json