Speaker Detection Module

The Buddie earphones have a built-in gyroscope sensor that implements voice activity detection by analyzing z-axis vibration data.

File locations:

1. lis2de12.c
2. lis2de12.h
3. lis2de12_driver.c
4. lis2de12_driver.h

Below we will briefly introduce this module according to the order of earphone operation

Function Entry	Function Description	File Location
bone_task_init()	SPI peripheral initialization, and register vad_task and callback function	apps\earphone\app_main.c
bone_task_timer_cb()	Read sensor data	apps\common\device\gSensor\lis2de12.c
vad_task()	Execute trigger task	apps\common\device\gSensor\lis2de12.c

1 Entry Function and Task List

File location: apps\earphone\app_main.c -> app_main() -> bone_task_init() This function will execute the following steps:

1. Register SPI peripheral and start the sensor peripheral.
2. Create "vad_task" task. (Note: the vad_task needs to be manually registered in task_info task_info_table[] before compilation)
3. Add timer task and callback function to collect z-axis data

2 vad_task()

File location: apps\common\device\gSensor\lis2de12.c This function will execute the following steps:

1. Perform FFT operation on the phone's z-axis data to obtain frequency domain data
2. Analyze the frequency domain data to obtain voice trigger threshold