SMT156

Note

This is a preliminary profile based on a diagnostic report on GitHub. It covers a genuine OEM, generic-market SMT156 wall panel identified through the owner’s ELC and OEM product evidence, but it has not been validated on hardware available for local testing. Climate support is optional, and USB or vendor root and persistent unlock routes remain untested.

The maker is probably Electron (Shenzhen Electron Technology, ELC), which lists it as the SMT156 on its own site, and its firmware uses the same ZX-SMT…-R… naming as Electron’s WF2489T build. No owner has yet read its ro.product.odm.manufacturer, so this is unconfirmed.

This 15.6 in Android wall panel identifies its firmware as ZX-SMT156 and its exact model and device as rk3566_t. The _t device identifier is the reliable discriminator: generic rk3566 matching would collide with the unrelated TPA10 and S9E.

Also sold as

ZX-SMT156, SMT156, RK3566_T, rk3566_t, generic 15.6 inch SMT156 wall panel (ELC OEM). Firmware ZX-SMT156-R128V1.2B-15.6-GG-J4.79U-20250926.

Profile fingerprint	model and device rk3566_t; reported firmware ZX-SMT156-R128V1.2B-15.6-GG-J4.79U-20250926
SoC	Rockchip rk3566, four cores, rk30board hardware
Android	13 (API 33)
ABI	arm64-v8a, with 32-bit compatibility
Display	1920×1080 at 160 dpi, 15.6 in
RAM and storage	4 GB / 32 GB
Root	no app-accessible su on the reported installation; USB adb root, vendor engineering mode and persistent unlock routes were not tested
RGB LED	app-direct /dev/ledjni, confirmed working
Sensors	binary proximity and ambient light confirmed; GXHT30 climate inputs identified through reporter-supplied adb shell evidence
System WebView	Google WebView 149.0.7827.164 reported; current enough for the Home Assistant frontend
Relays	present in the vendor’s own MQTT implementation according to the reporter, but no Android or sysfs control path has been identified
Released	Not confidently dated; the earliest archived listing found for this OEM product is from January 2025, which confirms it existed by then but not when it first shipped (earliest archived elclcd.com listing, Wayback Machine, January 2025)

Panel app support

The bundled zx-smt156.yaml profile provides the correct identity and explicitly routes the working /dev/ledjni RGB controller. It uses a conservative LED transfer curve until a reporter supplies a measured response. Standard Android brightness, light and proximity sensing, navigation, the Home Assistant entities and the built-in dashboard work without root.

The profile exposes Room temperature and Room humidity as an optional extra, not part of the core support. Reporter evidence shows sun-ths temperature in hundredths of a degree Celsius on ABS_THROTTLE, and sun-hum relative humidity in hundredths of a percent on vendor axis 0x1d. The panel app reads these nodes through its allowlisted root helper. When the helper is unavailable, no room-climate reading is published. A local temperature calibration offset is available, because the panel’s self-heating has not been characterised.

The reported installation had no app-accessible su, but USB adb root, vendor engineering mode and a persistent unlock route are uncharacterised rather than ruled out. Runtime probes decide which routes exist, and each privileged route is checked when used. Until one is established, true backlight-off, reboot and root-only controls need an installed helper; the core ZX-SMT156 support does not require those root-only controls. The profile deliberately declares no relay path, because inventing one from the vendor’s MQTT feature list would risk controlling the wrong sysfs device.

Characterising missing hardware

Diagnostics include a bounded [hardware] block with input device names, bound I²C and IIO names, thermal zone types and likely relay-class entries. That report identified the sun-ths and sun-hum input devices; the relay path remains unknown. The next useful relay evidence is the package name of the vendor’s MQTT service and its narrowly scoped traffic while an attended test toggles one relay.

For the sun-ths and sun-hum input devices, download and run the read-only collector below. Replace <panel-ip> with the panel’s address, then paste the complete line into the same Git Bash, WSL, macOS Terminal or Linux terminal where adb works:

curl -fsSL https://raw.githubusercontent.com/panel-assistant/android/v0.9.11/scripts/collect-panel-hardware.sh -o collect-panel-hardware.sh && bash collect-panel-hardware.sh --serial <panel-ip>:5555 --observe climate

This only reads the two climate input devices and does not change the panel. The live observation is limited to 10 seconds and 32 events per exact sensor name. Review the terminal output before sharing it; if the command reports an error, share that error instead. The 2026-07-17 adb shell report established the input names, axes, and values consistent with hundredths scaling. A reporter comparison of the panel app’s readings against the vendor display or an external thermometer and hygrometer is still needed before calling them hardware-validated. Being readable from an adb shell does not give an ordinary app access; the panel app uses the installed allowlisted helper.

No public firmware source has been found for this model. Preserve a firmware and recovery backup before modifying the vendor installation, and share only hardware metadata, not firmware files, in a public issue.