Adds end-to-end support for driving USB-connected Adalight / AmbiLED
LED controllers from Android TV boxes. Android's security model blocks
direct USB access from Python, so writes route through a Kotlin
UsbSerialBridge singleton via Chaquopy.
Python side:
- New SerialTransport Protocol (serial_transport.py) with open / write /
flush / close. Desktop uses PySerialTransport (wraps pyserial),
Android uses AndroidSerialTransport (wraps the Kotlin bridge).
- list_serial_ports() factory returns desktop COM ports on desktop,
USB devices on Android — callers don't branch.
- URL scheme extended: existing COM3[:baud] and /dev/ttyUSB0[:baud]
unchanged; new usb:VID:PID[:serial][@baud] for Android (@ is the
baud separator since : is already used between VID and PID).
- AdalightClient and SerialDeviceProvider refactored to go through
the transport — no more direct pyserial imports in hot paths.
- 17 new unit tests cover URL parsing, PySerial transport, factory
selection, platform-branching discovery. Full suite 750 passing.
Kotlin side:
- UsbSerialBridge.kt singleton uses com.hoho.android.usbserial (mik3y)
which ships drivers for CH340, CP2102, FTDI, Prolific, and CDC-ACM
(Arduino). Exposes listDevices, open, write, close via @JvmStatic
for Chaquopy. First open() attempt without permission triggers the
system USB permission dialog; next call succeeds once user grants.
- usb-serial-for-android is distributed via JitPack — added that repo
in settings.gradle.kts and the dependency in app/build.gradle.kts.
- AndroidManifest declares uses-feature android.hardware.usb.host
(required=false so non-USB-host phones still install).
- LedGrabApp.onCreate calls UsbSerialBridge.init(this) so the bridge
resolves the UsbManager without needing an Activity ref.
Verified: ./gradlew compileDebugKotlin succeeds; off-Android import
of android_serial_transport works. Real-hardware smoke test on a
TV box with a CH340/CP2102/FTDI adapter still pending.
ESP-NOW (espnow_client / espnow_provider) still imports pyserial
directly because it needs bidirectional reads — separate refactor
to extend the transport with read() if that path ever needs Android
USB support.
