Request examples for built-in StackChan sensors (LTR553, BMM150, ST25R3916)

[xuruiray]

I am working on a local StackChan firmware build and trying to expose all built-in hardware sensors in a local Web UI. The product page lists LTR-553ALS-WA proximity/ambient light, BMI270+BMM150 9-axis IMU, ST25R3916B RFID/NFC, and INA226 power monitor.

I checked the current BSP examples and found working examples for INA226 and NFC detection, but I could not find examples for the built-in LTR553 proximity/ambient-light sensor or BMM150 magnetometer.

What I found so far:

• StackChan-BSP initializes M5StackChan, touch, IO expander, servos, and INA226.
• StackChan-BSP has an NFC Detect example using M5UnitUnified + UnitNFC on M5.In_I2C.
• The Home Assistant/ESPHome documentation includes LTR-553ALS-WA at I2C address 0x23, but marks BMM150 as not supported yet / WIP.
• M5Unified appears to access BMM150 through the BMI270 AUX bus at address 0x10, not as a direct main I2C device. This is an important detail for native firmware implementations.
• The Arduino StackChan LTR553 docs use the separate LTR5XX library and call light.begin(), setPsMode(), setAlsMode(), then getPsValue()/getAlsValue().

Could you provide or point to the recommended built-in sensor examples/APIs for StackChan, especially:

1. LTR553 proximity and ambient light on the internal I2C bus.
2. BMM150 magnetometer access through BMI270 AUX, including the correct axis mapping for StackChan.
3. ST25R3916B built-in NFC/RFID initialization details for non-Arduino / native ESP-IDF firmware.
4. The expected internal I2C scan result for a healthy StackChan unit.

This would help third-party local firmware projects avoid treating these advertised sensors as unavailable or probing them incorrectly.

[Forairaaaaa]

Hi, for 2 you can refer to the M5Unified IMU example.