This is how to add velocity sensitive midi to the Roland TR-77 drum machine using Tubbutec Unipulse.
Installation is very strait forward, you just need to solder some wires and drill holes for the Midi socket and learn button. To get a sound over midi, the machine needs to be started and no pattern selected.
This manual is just a brief description of how to install the uniPulse, for further information please check out the uniPulse page.
Trigger points are shown for all 13 instruments including Maracas:
This is where to get the supply voltage for the uniPulse:
And this is how the installed uniPulse board looks like: