The DG was intended to work with the free FluidSynth app, running on an Android phone.
Some have tried it with an iPad for example running Bismarck bs-16i. This seems to work OK most of the time but there are some bugs.
The main one is that when you stop cranking, sometimes a note can get stuck in the ON state and you have to unplug and plug the DG in again to the iPad to restart it. Am working on a software upgrade to try and fix it but even if I send a MIDI command to turn off every single note if crank has stopped turning for >1 second, the issue still happens sometimes which makes me wonder if it is an issue with bs-16i. Working on it !