MES events

Events and event values are generated in the Message Event Service (MES). Using MES events allows orderly interactions between the micro:bit and external devices. These events are sent to and received from other wireless devices paired with the micro:bit (phone, game pad, etc.).

The event source IDs represent a device feature category. The event values are actions for, or notifications about a device feature.

MES system sources

The MES events are defined in this source file of the microbit-dal:

MESEvents.h

Also, you can see how the message bus works in the DAL core files:

Raised events

Events are generated, or raised, for by the micro:bit for a paired device. These are raised using the raise event function.

control.raiseEvent(
    control.eventSourceId(EventBusSource.MES_REMOTE_CONTROL_ID),
    control.eventValueId(EventBusValue.MES_REMOTE_CONTROL_EVT_VOLUMEUP)
);

Remote control

Events for using the micro:bit as a remote control for audio play.

MES_REMOTE_CONTROL_ID

MES_REMOTE_CONTROL_EVT_PLAY: Play the current track
MES_REMOTE_CONTROL_EVT_PAUSE: Pause the current play in progress
MES_REMOTE_CONTROL_EVT_STOP: Stop playing and reset to the beginning of the current track
MES_REMOTE_CONTROL_EVT_NEXTTRACK: Skip to the next track
MES_REMOTE_CONTROL_EVT_PREVTRACK: Skip to the previous track
MES_REMOTE_CONTROL_EVT_FORWARD: Move forward in the current track
MES_REMOTE_CONTROL_EVT_REWIND: Move backward in the current track
MES_REMOTE_CONTROL_EVT_VOLUMEUP: Increase the play volume (audio)
MES_REMOTE_CONTROL_EVT_VOLUMEDOWN: Decrease the play volume (audio)

Camera

Control camera actions on a paired device.

MES_CAMERA_ID

MES_CAMERA_EVT_LAUNCH_PHOTO_MODE: Turn on or set the camera to photo mode.
MES_CAMERA_EVT_LAUNCH_VIDEO_MODE: Turn on or set the camera to video mode.
MES_CAMERA_EVT_TAKE_PHOTO: Capture the picture in the camera view.
MES_CAMERA_EVT_START_VIDEO_CAPTURE: Begin capturing video (start record)
MES_CAMERA_EVT_STOP_VIDEO_CAPTURE: End capturing video (stop record)
MES_CAMERA_EVT_STOP_PHOTO_MODE: Stop photo mode and return to the default mode
MES_CAMERA_EVT_STOP_VIDEO_MODE: Stop video mode and return to the default mode
MES_CAMERA_EVT_TOGGLE_FRONT_REAR: Switch from the front camera to rear camera or rear to front

Alerts

Trigger standard alert notifications on a device.

MES_ALERTS_ID

MES_ALERT_EVT_DISPLAY_TOAST
MES_ALERT_EVT_VIBRATE
MES_ALERT_EVT_PLAY_SOUND
MES_ALERT_EVT_PLAY_RINGTONE
MES_ALERT_EVT_FIND_MY_PHONE
MES_ALERT_EVT_ALARM1
MES_ALERT_EVT_ALARM2
MES_ALERT_EVT_ALARM3
MES_ALERT_EVT_ALARM4
MES_ALERT_EVT_ALARM5
MES_ALERT_EVT_ALARM6

Received events

Events are received by the micro:bit from a paired device. You capture these in an on event function.

control.onEvent(EventBusSource.MES_DEVICE_INFO_ID, EventBusValue.MES_DEVICE_INCOMING_CALL, () => {

})

Carrier signal strength

Signal strength to the subscribed carrier service.

MES_SIGNAL_STRENGTH_ID

MES_SIGNAL_STRENGTH_EVT_NO_BAR: No service available or very low signal strength
MES_SIGNAL_STRENGTH_EVT_ONE_BAR: Low signal strength
MES_SIGNAL_STRENGTH_EVT_TWO_BAR: Medium signal strength
MES_SIGNAL_STRENGTH_EVT_THREE_BAR: High signal strength
MES_SIGNAL_STRENGTH_EVT_FOUR_BAR: Full signal strength

Device information

Information about the current status of the device

MES_DEVICE_INFO_ID

MES_DEVICE_ORIENTATION_LANDSCAPE: Display orientation is now in landscape
MES_DEVICE_ORIENTATION_PORTRAIT: Display orientation is now in portrait
MES_DEVICE_GESTURE_NONE: No gesture detected for device activation
MES_DEVICE_GESTURE_DEVICE_SHAKEN: The device was shaken
MES_DEVICE_DISPLAY_OFF: Device display is now turned off
MES_DEVICE_DISPLAY_ON: Device display is now turned on
MES_DEVICE_INCOMING_CALL: Currently receiving an incoming call
MES_DEVICE_INCOMING_MESSAGE: A message was received (SMS or other messaging app)

Game pad controller

Button events from a paired game pad.

MES_DPAD_CONTROLLER_ID

MES_DPAD_BUTTON_A_DOWN: Button A pressed
MES_DPAD_BUTTON_A_UP: Button A released
MES_DPAD_BUTTON_B_DOWN: Button B pressed
MES_DPAD_BUTTON_B_UP: Button B released
MES_DPAD_BUTTON_C_DOWN: Button C pressed
MES_DPAD_BUTTON_C_UP: Button C released
MES_DPAD_BUTTON_D_DOWN: Button D pressed
MES_DPAD_BUTTON_D_UP: Button D released
MES_DPAD_BUTTON_1_DOWN: Button 1 pressed
MES_DPAD_BUTTON_1_UP: Button 1 released
MES_DPAD_BUTTON_2_DOWN: Button 2 pressed
MES_DPAD_BUTTON_2_UP: Button 2 released
MES_DPAD_BUTTON_3_DOWN: Button 3 pressed
MES_DPAD_BUTTON_3_UP: Button 3 released
MES_DPAD_BUTTON_4_DOWN: Button 4 pressed
MES_DPAD_BUTTON_4_UP: Button 4 released