How I hacked this technology to not only be an instrument but a light show! PART 2 - UNDER THE HOOD

Hi, my name is Jack St. James and I am one half of the electro pop band Avec Sans. Previously I wrote an introduction on how I hacked the Novation Launchpad to not only be an instrument but a light show. If any of this post sounds confusing then check out part 1 as it covers all the basics.

My intention was to post part 2 a week after part 1, but things rapidly got pretty busy for the band...

Also @thisisbenbrick has been bugging constantly to post again!

>> So, apologies for the delay and here we go! <<

Part 2 will cover exactly how to hack the Launchpad in to displaying a light show.

THE BASIC THEORY
The lights on the launchpad are essentially designed to do one of three things:

1. As a physical and visual representation of the clips in Ableton.
When you are running Ableton in clip view you drag your sounds on to clips, assign the clip a colour and then by clicking on that clip it plays the sound. Since you only have one mouse you can only launch one clip at a time. With the Launchpad it reflects the Ableton screen and allows you to play, stop and record multiple clips in the fly since you have 10 fingers. Simply put, It takes what's on the screen and can turn it in to a playable instrument.

2. As a physical mixer to use while you perform.
This part isn't important to this article to I'll gloss this one over.

3. To give you visual feedback when pressing a button.
If you want the Launchpad to give you visual feedback when you press a button (i.e. to light up as you press it (like in the Tom Hanks movie, Big)) you can use a midi loop to achieve this.

Remember, the Launchpad doesn't do any processing itself - it is merely a controller for Ableton. So in order for a light on the Launchpad to turn on Ableton will need to do the processing. You will need to set up Ableton to receive a midi note from the Launchpad and then send the same midi note back to the Launchpad. This will signal that button to turn on the LED light.

As you can see in the screen grab below I have set the midi channel to receive midi from Launchpad Mk2 Input and then send the midi back out to Launchpad Mk2 Output

And it's this midi feedback loop which unlocks the trick to hacking the Launchpad! Let me explain...

By sending midi back to the Launchpad it turns on a light when you press the button right? So what if you create a midi channel with pre programmed notes in it? Essentially tricking the Launchpad into thinking someone has pressed a button and it should therefore turn on the light! Not only that, but because you are pre-programming the midi notes you can also assign them a velocity value which controls the colour of the light when it turns on.

All you need to do is create a midi channel > set the midi output to the Launchpad > program in some midi notes > press play > watch it light up!

Now, the theory of this is the easy part. All it took was working out to remove the middle man and let the computer send the midi notes. The hard part is actually programming something that looks good! It's very much like having to create an animation, but in binary. If binary consisted of 64 buttons which have 127 colour values. It's a LONG process. These are the midi notes i programmed for one half of a chorus for 1 of my 3 launchpads which I use live for 1 of the 14 songs we can preform live:

It can take 2 weeks per song to program! This is what our setup looks like in Ableton. Note the Yellow channels called Lights. Those clips contain all of the midi I send to the Launchpads.

So that's it in a nutshell. If you got stuck at any point I also made a video tutorial a couple of years ago which takes you through the steps!