How to detect Bluetooth input from an external scanner

Question

I have a problem.

I am trying to integrate a scanner (which acts like an external bluetooth keyboard) into my Android app.

The problem that I cannot understand is how to determine when the keyboard will send a message to my application.

The scanner works and the text is displayed inside any editing text, but I want to make some changes to it.

I tried to find an intent filter to turn on the receiver for an event that fires when a Bluetooth device sends a message, but I cannot find a good one.

Can anyone point me in a direction?

Thanks Arkde