How do I use MIDI library to send a 5V trigger pulse on NoteOn message?

Hi. My name is Steve. I am currently building a standalone analogue synth unit using an SN-Voice PCB from Magic Smoke/SMS Audio. The device generates PWM square waves, triangle wave and noise and is calibrated to 1V/Oct. I have built a small step sequencer to use with it but would like to make it sensitive to Midi so have been experimenting with THE 4192 DAC and a sketch by Mr.Book to control a Gakken synth via MIDI. I am interested in using the MIDI library to basically generate a voltage trigger pulse from a note on message to connect to the Gate in of the SN voice and a CV for the pitch connected to the 1v/oct input. I have had some success with generating pitches from the keyboard to the snvoice but it is unstable. Could anyone here help with this? Thanks, Steve (London.)

I have worked my way around the code for the Midivox CV sketch. I can now trigger the gate input of my SNVoice box from pin 5 of the Arduino and play midi notes from the M-audio midi keyboard! It just involved connecting the pins of the 4192 DAC to the right arduino pins as in the Midivox schematic, setting up the MIDI-IN part of the circuit and uploading the sketch. Its quite well tuned as well which came as a surprise.