Currently, Bluetooth MIDI works for iPads and most Mac computers. But you can get Windows computers to utilize a Bluetooth MIDI connection, with a little extra effort.
Windows computers are also Bluetooth MIDI capable using the instructions in this article here: http://newbodyfresher.linclip.com/how-to-use-with-daw.
Watch this video to see how to set up Bluetooth MIDI on a Mac: https://www.youtube.com/watch?v=TuRXxqNGp5o
How to set up Bluetooth on an iPad:
On an iPad, go to your iPad’s settings and scroll all the way down on the left hand side and click on Piano Marvel. Make sure that you choose the setting to allow Piano Marvel to utilize Bluetooth on your device. Make sure your Instrument’s Bluetooth is turned on and connected to your iPad. Then go into Piano Marvel and log into the app. Go to the Menu, Instrument Settings and select your Bluetooth connection from the list there. You should then be able to play a note on your piano and see the blue circle in the middle of the Instrument Settings page flash. You will then be able to use your Bluetooth MIDI connection to receive feedback and grading in Piano Marvel.