Midi Light Show using Arduino

For a class, my teammate and I decided to develop a MIDI based system that has a responsive light for each note played.  For example, if you plug our little setup to a keyboard, pending on which note you press, you’ll get a specific color.  You’ll need a list of several items, but the reward is quite nice!  Plus, there are a lot of possible improvements and developments from the original idea, so please take the liberty to expand on this concept once you’ve put everything together.

Step 2: Putting It All Together

The main format of this schematic is that each pin of the LED is connected to a different pin on the Midi Shield.  note the lower voltage for the red leg of our LED. The cathode goes to ground.  The midi shield connects on top of the Arduino, which is why extended headers are necessary for the function of our lights. This is an extremely simple and straightforward build, but it provides a lot of room for expansion as well.

Step 3: Midi Concepts…

To program with Midi, you must understand a few key concepts that determine how the information is read.

Midi sends information with 3 bytes of information at a baud rate of 31250. The first byte determines whether a note is turned on, the next byte determines what pitch is played, and the third byte determines the volume of the note.  It is important to note the order of the information as if you don’t set the code to read in this order for only 3 bytes, funny things start happening. Trust us.

Consider the following code:

//reads the serial port to see if there is any incoming information
boolean check_midi()
{
   while (Serial.available() >= 3)//when three bytes available
   {
     if (Serial.available())
     {
       digitalWrite(3,HIGH);    
       location_byte = Serial.read();//read first byte
       in_note = Serial.read();//read next byte
       in_volume = Serial.read();//read final byte
       return true;
     }
   }
}

For more detail: Midi Light Show using Arduino