About 6 months ago, there was an Indiegogo drive for a Wireless Midi interface. It got funded in June.
“Let your old but good digital piano shine again by connecting your iPhone or iPad via Bluetooth wireless MIDI interface.”
Basically, it takes the voltage that is being transmitted on the midi ports and uses that to convert it to Bluetooth Low Energy (BLE). Which means this little $45 thing you plug in will allow you to talk to your iPad, iPhone, Mac or anything that supports Bluetooth Low Energy (Bluetooth 4).
So, how does this work with an EWI?