For this demo, there are two free iOS apps that you will need to install on your iOS device:
First, you will need to open midimittr on your iPhone or iPad. This app is used to route BLE MIDI messages to MIDI capable iOS apps like Perfect Piano.
Once midimitter has opened, click on the icon on the top left of the screen to show the menu.
Then, select the clients tab.
Next, select the Adafruit Bluefruit LE device from the clients list. If you do not see your UNTZ, you will need to make sure that you have uploaded one of the BLE examples, and that your UNTZ is powered on.
Once your UNTZ is connected, you can now navigate back to the routing tab.
In the routing tab, select the Bluefruit as a source.
Now that we have the Bluefruit connected, we can open up Perfect Piano. This app is a free example of many MIDI capable software synths in the iOS App Store. Each app might have slightly different requirements to use MIDI input, but Perfect Piano makes it easy.
Open up the app to get started, and select the keyboard.
You should now see a full screen keyboard like the one shown below.
You should now be able to press buttons on the UNTZ to trigger sounds in Perfect Piano.
The video below shows basic communication between the UNTZtrument and Perfect Piano on an iPad over Bluetooth LE MIDI.