Wednesday, January 25, 2012


Back in Fall 2011, I decided to build a RGB variable color lightbox for a Power Electronics class (6.131). Since the existing [sleek] LED lightboxes on the market were about $50+, emitted white light, and didn't do much else, I wanted to make something that could do more. I wanted to be able to adjust the light color, the slope of the lightbox screen, be able to make and attach custom widgets (like my sliding T-square, or a future eraser-crumb gutter / pen holder, hidden shelves), etc - almost like a portable desk. For the class, I had to satisfy the power electronics part, so in hindsight, maybe I should have actually just made a motor controller. But afterwards, I still really wanted to make the actual lightbox product, so I started over, this time using an ARDUINO! For the first time! :D

Here's what I've got so far - a mess of wires (soon to be sorted), and 3 sliding 10K potentiometers on the left  that control the red, green, and blue color values. For the background soundtrack, you can listen to the two Jordan's at MITERS (the female of whom has an awesome blog: [T3CHNOLOCHIC]) discuss 'hella Bohemian (?)' for some reason:

(Apologies for shaky one-handed iPhone recording!)
Above: Video of RGBeta testing.

Thanks to Charles ([ETOTHEIPIPLUSONE]) for supplying me with the Arduino Nano and LED strips!

Arduino's are awesome (haha)! I write a bit of code, upload it to the Arduino, connect it to some LEDs and potentiometers... and things magically work! Plus, what's cool is that this little Arduino can do all the PWM magic digitally that I had to do analog-ly before for my class. Here was the first thing I made using it:

Above: Yay single RGB LED! Making it fade using an Arduino Nano.

In the above photo, I'm actually using a leftover Piranha LED that I bought for class, shipped from the UK. These little RGB LEDs gave me more trouble than expected, as the supplier website didn't have a datasheet, and after testing them I found that the LEDs were common ANODE [+] (whereas my design was tailored to common CATHODE [-]). Here are some surviving photos of my RGB lightbox, ALPHA version:

Above: It uses 3 buck converters, and (in this photo) is missing
2 power resistors and 2 potentiometers. The lightboard stacks on top.

Above: RGB lightbox Alpha testing. Sadly doesn't work quite as well,
and (in this photo) I've already blown a piranha LED just testing the first row, haha.

Comparing with what I have now, RGBeta is not as impressive looking as RGB Alpha, which had 3 legit-looking inductors and power resistors, as well as a separate board complete with 3 H-bridges (only lowsides used). But RGBeta is definitely cleaner and lighter, as well as less painful to make and debug. In fact, the only major debugging issue I ran into was because I forgot to make a common ground (my most common mistake), which ended up creating a flickering unstable light that semi-responded to the potentiometer slides. Grounding issues aside, RGBeta was definitely much easier to create.

Above: RGBeta is definitely more boss that RGB Alpha.

Side note: I've been unknowingly shortening my current 'RGB lightbox' to 'RGBeta' (pronounced R - G - Beta), since I consider this version the Beta version (the Alpha one being the one I made for class). Though, 'Beta' is probably not the right term to use, since this isn't a software release. What's more, every time I say it, it reminds me of RGVeda, the debut manga of CLAMP, and RigVeda [wiki], a sacred text of Hinduism - even though my lightbox is completely unrelated, haha. :)

Why do I want a lightbox? I confess, I'm biased as an artist and I'll mainly be using it to ink over sketches and learn animation. However, because it'll be a portable desk, the uses for it are limitless. (If I add a detachable cushion-y underside to the lightbox, I could set my laptop on top and have a comfy laptop lap desk, too! :D ). I discovered another use when Bailey ([ISOPACK]) was using a light to match up 2 printed circuit designs (for the top and bottom layer of the double-sided copper clad), in preparation for etching.

Above: Bailey's printed designs, in prep for DIY etching a printed circuit board.

I just need to solder on some more LED strips, provide a portable power supply, transfer circuit from breadboard to PCB (or other), design the frame and then build it!

In other news, I'm assistant choreographer to the 'Hack, Punt, Tool' original MIT screenplay put on by the MIT Musical Theater Guild, and hectic production week starts next week! It's my first time helping them out, and they're a cool bunch - lots of creative set/prop/costume builders! I was talking with the Head Choreographer TaunTaun, and we were lamenting how there wasn't a program that could help choreographers and directors do blocking and formations. As a dancer who has choreographed for several people, I also find it sad that the best of us resort to drawings and powerpoint slides to convey position. But usually in the end, all of us resort to pointing and physically moving people to where they're supposed to be. But that approach is time-consuming and often confusing for the dancers. If there was a program that could allow the choreographer to create and edit formations of people, atop a background of their choice (stage or theater set), synced with a soundtrack of music or lines (basically like a UI to making a simple animation), we wouldn't have to resort to doing something like this:

Above: An approach we used to block out a scene in Killian Court,
using spools as cast members. Later, one of the directors even made a
mini model of the set so we could visualize the space.

It sounds like this program could help anyone that just needs a quick way to explain a series of positions - dance formations, chess/checkers/go/board game strategies, WWII troop movements for history presentations, sports play strategies, film/book/comic storyboarding, re-creation of events, etc. This idea already ended up on the list of things I wanted to make, so let's hope I get to it soon!


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