This video update shows how you use a phone to play the MIDI data coming out of the DigiGurdy.
The soundfont file (.sf2 format) has to have been uploaded onto the phone in advance. I will make this file available soon. All the sounds to be played are stored in this file.
The MIDI player I am using is called FluidSynth and is available free from the Google Play store for Android phones. An Apple version also exists but I have not tried it with the DigiGurdy.
The DigiGurdy outputs data on 5 MIDI channels. In FluidSynth we must assign an instrument or sound to each of these 5 channels for it to work correctly. This is best explained with a video and so the video below shows me setting up Fluidsynth on a phone in this way. FluidSynth has a very basic user interface but it also has very low latency (time between pressing a key and hearing the sound) and so works well with the DigiGurdy.