Bluetooth Connection Events¶
Introduction¶
Two MicroBitEvent types are available for tracking changes in the state of Bluetooth connections between remote devices and the micro:bit.
MICROBIT_BLE_EVT_CONNECTED¶
This event is produced when a remote peer device connects to the micro:bit over Bluetooth.
To listen for this event:
uBit.messageBus.listen(MICROBIT_ID_BLE, MICROBIT_BLE_EVT_CONNECTED, onConnected);
MICROBIT_BLE_EVT_DISCONNECTED¶
This event is produced when a remote Bluetooth device disconnects from the micro:bit.
To listen for this event:
uBit.messageBus.listen(MICROBIT_ID_BLE, MICROBIT_BLE_EVT_DISCONNECTED, onDisconnected);
Example micro:bit application - Keeping track of connection state¶
Connected | Disconnected |
---|---|
#include "MicroBit.h"
#include "MicroBitSamples.h"
MicroBit uBit;
int connected = 0;
void onConnected(MicroBitEvent e)
{
uBit.display.print("C");
connected = 1;
}
void onDisconnected(MicroBitEvent e)
{
uBit.display.print("D");
connected = 0;
}
int main()
{
// Initialise the micro:bit runtime.
uBit.init();
// listen for Bluetooth connection state changes
uBit.messageBus.listen(MICROBIT_ID_BLE, MICROBIT_BLE_EVT_CONNECTED, onConnected);
uBit.messageBus.listen(MICROBIT_ID_BLE, MICROBIT_BLE_EVT_DISCONNECTED, onDisconnected);
uBit.display.scroll("READY");
// If main exits, there may still be other fibers running or registered event handlers etc.
// Simply release this fiber, which will mean we enter the scheduler. Worse case, we then
// sit in the idle task forever, in a power efficient sleep.
release_fiber();
}