Painting with the Novation Launchpad

This is a personal project I started to see if i could use my Novation Launchpad to paint. Basically, to see if i could use the 8x8 grid as an output device, or a very low resolution screen. Also, to try to learn some Max/MSP in the process.

At first I downloaded the Launchpad programmers reference but found it too advanced for my initial purposes. This controller is able to send and receive MIDI data in order to light up the LEDs that are in the matrix. So my initial guess was to just use some sort of matrix interface in Max and map it to the MIDI notes that make them light up. The decimal equivalent for the Launchpad LEDs is this:

From the reference manual

What this means is that if you send a MIDI note with note number 0 and a velocity number as indicated in the following table:

Also from the manual

The top left led in the matrix will light up in the desired color. So far, so good. The problem was that the matrix control in Max doesn't have the same format, it uses column and row number at the output. to convert this into the MIDI note that you want I simply did this:

MIDI Note =  column  + 16*row

So that the LED corresponding to the sixth row and third column then is 2 + 16*5 = 82 (since the first row and column number is 0,0). For the velocity a simple selector between the values 12, 15, 62, 63 and 60 was mapped to the circular buttons on the right of the launchpad, so the color is selected only from those buttons.

The patch has a few bugs still, like you have to go into edit mode and manually select the Launchpad input and output ports. However, you can download it here. I will edit this post later to include some images and videos from the patch working, so that is not so abstract.