Output Devices

AVR MIDI Controller

my project for this week was building an AVR MIDI Controller.

MIDI is the Musical Instrument Digital Interfaces. It is a serial protocol which enables  communication of digital musical devices such as keyboards, synth modules and mixing consoles. The MIDI connector has 5 pin but only 2 pins are used for the actual data.

I needed to connect the MIDI output pin to the UART input. Theoretically this looked like a simple task but you will see later on that it was not....

Surprisingly eagle auto routed my board very quickly !

First Board gone terribly wrong

I found that I inputed some bad params to the path.py tools, and the path that was created connected one of the resonator pads with another trace. I tried to correct this with an exacto knife and ended up ripping up the trace.

I decided to remake the board, which cost me another half a day.

My Oscillating Synth

How to use an Opto-Isolator to make a MIDI connector

Lesson 3: Read the reference material /  Trying to cheat physics usually fails

MIDI creates current, while the AVR UART needs a voltage difference.

Lesson1: Inspect path_view output Carefully !!!!!

Lesson 2: The Mathematics of knives and late hours

Lesson 4: Always put a serial interface on a complex board -

Flashing LED is not a good

debugging tool