arduino and midi input

i’ve been using the arduino for midi input and output for a while now, mainly using kuk’s input method, output is easy enough though. midi input had me stumped for a while, but he found adding 100k resistor to the base of the phototransistor of the optoisolator created a stable response which sorted it out.

theres alot you can do with variations of his code, and many people have used the circuit to build midi>cv convertors for analogue synths, but at the moment i’m mostly interested in building a clock source for analouge/digital sequencers so i can run them straight from the output of my HR-16 or tr-505 without the need for a computer based midi sequencer. the basic idea is to receive a midi clock byte and advance the count of a 4 bit binary output from the arduino to advance the steps of a multiplexer ic based sequencer.

midi clocks output 24 pulses per quarter note, so this needs dividing down to get the step response you need. the ever useful and highly inspiring code from littlescale comes in handy here!

more soon.