Home Studio Build #2 / by Music Orange

In my perfect world of composition desks, I would have an LED light indicator above each MIDI key that I could turn on and off, preferably with a choice of color. Writing for choir and need to keep track of vocal ranges? Just mark the lower and upper limits of each group with it’s own color (e.g. red for bass, orange for alto, etc.) Want to keep track of a handful of drum or string articulations while programming a part? Just mark each key as needed. As I mentioned in Part 1, Kontakt’s Komplete Kontrol keyboards do this to some degree but not in an easily configurable and customizable way. So, as long as I am already building a new desk I thought now would be the time to solve the problem. The solution I decided on is plain brute force - make a panel of 88 toggle switches that line up below each key, each of which can turn on a single LED above each key on the keyboard in two different colors. It’s a little extreme, but it makes for the quickest most direct route from wanting to keep track of a key and actually doing it. Plus, I do like the look of lots of toggle switches. I decided on the Doepfer LMK4+ keyboard because of it’s very nice weighted keyboard and because it comes without a case.

doepfer-lmk4-keyboard.jpg

I contacted them directly and they graciously supplied me with a to-scale drawing that I could open in Illustrator to measure and line up the switches and LEDs with each key. I decided it would be much easier to mount all the switches and LEDs on two metal panels which would attach to the desk instead of trying to mount them directly in the wood itself, so I created two panels in Illustrator and laid out all the switch locations.

music-orange-switches-leds.jpg

I sent the Illustrator file to a laser cutting place…

music-orange-laser-cut-panels.jpg

…and had them anodized and etched.

music-orange-anodized.jpg

Figuring out how to actually power the LEDs, what the load on the them would be, what resistors I’d need, etc. was beyond my Googling skills so I contacted my friend Kent Suzuki of Right Brain Electronics. For him this was child’s play and he quickly helped me select the correct LEDs, resistors, power supply, etc. for the project and explained how I’d have to wire it all up. I chose red/orange LEDs - toggling each switch one way will turn on one color, and toggling the other way will turn on the other color.

Here are the switches, LEDs, and resistors needed for the panels…

music-orange-panel-parts.jpg

This turned out to be a LOT of soldering…

music-orange-soldering.jpg

Here’s a portion of the front of the switch panel.

music-orange-switch-panel.jpg

Now it’s time to layout and build the desk, mount the switch panels, and finish the wiring.

-Michael