EventsΒΆ

An event is an asynchronous notification from the MetaWear board represented in the C++ API by the MblMwEvent struct.

Recording CommandsΒΆ

The board can be programmed to execute MetaWear commands in response to an event firing.

An event can be many things such as a data filter (average the accelerometer signal), a disconnect (the board has disconnected from the Bluetooth link), or even a timer (10 seconds have passed).

To start recording commands, call mbl_mw_event_record_commands. While in a recording state, all MetaWear functions called will instead be recorded on the board and executed when the event is fired.

To stop recording, call mbl_mw_event_end_record. This function is asynchronous and will alert the caller when it is completed via a callback function.

In this example, when an event occurs from the control_signal, the led blinks:

event_handler = FnVoid_VoidP_VoidP_Int(lambda ctx, e, s: event.set())
pattern= LedPattern(pulse_duration_ms=1000, high_time_ms=500, high_intensity=16, low_intensity=16, repeat_count=Const.LED_REPEAT_INDEFINITELY)
libmetawear.mbl_mw_event_record_commands(control_signal)
libmetawear.mbl_mw_led_write_pattern(self.board, byref(pattern), LedColor.BLUE)
libmetawear.mbl_mw_led_play(self.board)
libmetawear.mbl_mw_event_end_record(control_signals[0], None, event_handler)

In this example, we create an event that reads the temperature data signal every time the timer reaches 1000ms:

signal = libmetawear.mbl_mw_multi_chnl_temp_get_temperature_data_signal(d.board, MetaWearRProChannel.ON_BOARD_THERMISTOR)
logger = create_voidp(lambda fn: libmetawear.mbl_mw_datasignal_log(signal, None, fn), resource = "temp_logger", event = e)

timer = create_voidp(lambda fn: libmetawear.mbl_mw_timer_create_indefinite(d.board, 1000, 0, None, fn), resource = "timer", event = e)
libmetawear.mbl_mw_event_record_commands(timer)
libmetawear.mbl_mw_datasignal_read(signal)
create_voidp_int(lambda fn: libmetawear.mbl_mw_event_end_record(timer, None, fn), event = e)

libmetawear.mbl_mw_logging_start(d.board, 0)
libmetawear.mbl_mw_timer_start(timer)