Error 3300: Microbit extension BluetoothDevice is not set

Hello guys, please help me!

I try to use bluetooth to connect micro bit, but it appear an error. It said 'Error 3300: Error 1 in extension Microbit_Accelerometer: BluetoothDevice is not set'. How can I fix this?

Hello XD SlimGuy, welcome to the forum

Unfortunately, the Micro:Bit library is broken (and a bit old). MIT are working on a new one. In the meantime, you can use Bluetooth functions to communicate.

Some of the micro:bit extension should work, but I did not try lately.
The first question however, did your micro:bit connect ok?
Second question: why do you stop accelerometer updates upon connecting?
Third question: what is the code on your micro:bit?

I have the same problem. Can you help me? This is my code.


Make sure that you have the latest BLE extension and the microbit extension,
see: MIT App Inventor Extensions
Make also sure that Bluetooth is on, on your phone.
In that case you do not need to ask for permissions, it is built-in into the extension.

Then, what is your problem?