The on-board flash memory can also be used to store MetaWear commands instead of sensor data.

A good example of this feature is to change the name of a device permanently so that is does not advertise as MetaWear.

Recorded commands can be executed any time after being programmed with the functions in macro.h header file.

Recording Commands

To record commands:

  1. Call mbl_mw_macro_record to put the API in macro mode

  2. Use the MetaWear commands that you want programmed

  3. Exit macro mode with mbl_mw_macro_end_record

    MetaWear.mbl_mw_macro_record(device.board, 1)
    MetaWear.mbl_mw_macro_end_record(device.board, ref.NULL, callback);

Macros can be set to run on boot by setting the exec_on_boot parameter with a non-zero value.

MetaWear.mbl_mw_macro_record(board, 1); // ON BOOT
MetaWear.mbl_mw_macro_record(board, 0); // NOT ON BOOT

In this example, the LED will blink blue on boot:

// Start recording macro
MetaWear.mbl_mw_macro_record(device.board, 1)

// COMMAND - Create LED pattern
var pattern = new MetaWear.LedPattern();
MetaWear.mbl_mw_led_load_preset_pattern(pattern.ref(), MetaWear.LedPreset.BLINK);
MetaWear.mbl_mw_led_write_pattern(device.board, pattern.ref(), MetaWear.LedColor.GREEN);

// End recording macro
var promise = new Promise((resolve, reject) => {
  var macro = MetaWear.mbl_mw_macro_end_record(device.board, ref.NULL, MetaWear.FnVoid_VoidP_Int.toPointer(function onSignal(context, rec) {
    console.log('Macro created');
var rec = await promise;

Erasing Macros

Erasing macros is done with the mbl_mw_macro_erase_all method. The erase operation will not occur until you disconnect from the board.