March 2014 2
Two left hands and no passion nor time for learning piano or guitar? Try out this super simple Arduino Midi-Theremin! This simple Midi Theremin uses a HC-SR04 Ultrasonic Sensor (which is extremly cheap ~2-4€) and produces a MIDI-out signal, analog to the measured distance from an object. Apart from the Senor you only need an Arduino (in this case an Arduino Nano), some wire and some MIDI playing device.
Find the – still alpha – sourcecode here
Choosing the right optocoppler for your midi-in project (e.g. Arduino)
The headlines almost says it all: when building an midi-input device for an µC-project e.g. an Arduino or an Raspberry Pi project, the first thing the MIDI cable “sees” is the optocoupler. And is important to choose the right one.
A lot of ciruits relate to the “4N28”. This is a passive optocoupler and to be frank it causes a lot of problems in the standard setup which mostly are not identified as an electrical problem.
- no midi input at all
- random loss of midi notes
- random playing of other midi notes