Tuesday, April 19, 2016

DIY Hack: A Better Marquee (Part I)


Lighted marquee decorations are very popular at the moment. A stroll through the aisles of just about any craft store (locally, we have Hobby Lobby, Michael's, and A. C. Moore) will prove that out. You can get letters, symbols, words, snowmen, stars, and who knows what else. You can get them in chipboard, galvanized tin, wood, plastic, and more.

I'm not sure why they're so popular, but I like them, especially the galvanized tin. It has a well-used industrial feel to it, which isn't quite a cool as Steampunk, but cool just the same. There are two problems, though. The first is that they're ridiculously expensive, considering what they are. That 'C' at the top of this post? It's only about 10" high and costs about $25. Fortunately, Hobby Lobby is always running sales of that kind of stuff, and I got it for half that.

The second problem is that these decorations are very monochromatic. The lighted ones almost always have warm white LED illumination, which is great because they look more like incandescent bulbs that way; that suits the Industrial aesthetic well. But even if I could forgive the lack of color, there's no motion either. Give me a flicker. Give me a wave. Just don't put me to sleep!

My wife, Tammy, gave me a couple of letters last summer for my birthday, an 'M' and a 'D' (my initials). I decided to do something cool with them, but that project isn't quite ready for prime time just yet. That will be the subject of another post or two. Or three.

And my daughter, Anna, found herself a marquee snowman this past Christmas. It's very similar to this guy right here. It's cute, but boring. That's when I decided to hack a marquee piece, and spice it up a bit. I wouldn't dare take apart my daughter's snowman. That just wouldn't be nice.

As luck would have it, my friend Cole turned 50 in early March, and she had a party to celebrate. I hadn't seen her since we graduated from college waaaay back in 1988 (shame on me; she doesn't live that far away), and decided that I was going to her party. Keeping in touch on Facebook just isn't the same as seeing someone in real life!

And speaking of real life: Cole is a Social Worker by day, but by night, she's a wildly creative artistic type. She beads and makes jewelry and all kinds of cool stuff (see her Etsy shop here). Her tastes are very eclectic, always have been, and that makes getting her a gift a very daunting task. What's an engineer to do? Well, make her something, of course!

I would never presume decorate someone else's walls, but Cole provided the perfect inspiration for my Marquee Hack. My daughter's snowman is safe for now; I went out and bought the "Galvanized Tin Lighted Letter C" you saw at the top of this post, went down into the Man Cave, and started getting creative.


The Concept
My friend Cole is more than just colorful - she's a whirling, twirling, endless kaleidoscope of color. This project cried out for animated, colored lights. Simply tinting the globes of the existing lamps just wouldn't do - too static. No, this project required some simple high-tech to bring it to life. I didn't have time to re-invent the world, though, so I went to my bread-and-butter solution to this sort of problem: neoPixels and an Arduino. My plan was to strip out the lamps that came with the marquee and replace them with neoPixels, and I'd use glass marbles to give the appearance of bulbs. An Arduino would run the show. It would need a pushbutton to select among a variety of light patterns, and a potentiometer to control the brightness. Because neoPixels can be power-hungry (up to 60mA per pixel if each of the red, green, & blue elements is on at full brightness), I decided to also remove the battery holder and use a 5V wall-wart power supply instead. Easy enough.


I can't even count the number of projects I've done using neoPixels and Arduinos. Most often, I've used the 5V, 16MHz Pro Mini for the brains of the operation. I've also used the Uno and the Mega, but the Pro Mini is tiny, powerful, and so inexpensive as to be almost disposable. The name-brand version is about $10, but I've found good-quality clones domestically for $5 and overseas (from China, usually) for $2.50 or less. As usual, the more you buy, the lower the price. I usually keep a bunch handy for just these types of spontaneous occasions. The Pro Mini is also available in a 3.3V version, but I don't use it for neoPixel projects because neoPixels require 5V.

Be very careful when buying from places like ebay, especially from overseas vendors. Many times, the description of the item doesn't match the title, and you may end up with a 3.3V board instead of a 5V. There's a lot of cutting and pasting going on, and not enough reading and understanding. When in doubt, ask!

I've also found neoPixels available in many different forms both domestically and overseas. Adafruit has perhaps the best selection domestically. The prices are a bit steep, but the service is excellent and fast. When I need a neoPixel ring, Adafruit is the best (and perhaps only) game in town. For discrete pixels or for strips, though, there are many choices. Just search ebay for "WS2812" and you'll find thousands.

When I need a small, flat footprint, but don't want to make or assemble my own circuit boards, I especially like the pixels shown in these photos. It's a single neoPixel on a 10mm PCB (the pads are on the back). I buy these still panelized, making them even less expensive - about $17 per 100, the last time I ordered. That's WAY less expensive than Adafruit - but it might take 3 weeks for them to arrive from China!

The lamps that come with the marquee letter are LED versions of 3V flashlight bulbs. They have a threaded base and glass envelopes (approximately 16mm in diameter) around the warm white LEDs, and are reasonably high quality replacements for incandescent bulbs. I happened to have clear, glass marbles on hand (from an entirely different project) that were just about the perfect size to replace the bulbs.

Next Time...

Rather than try to cram details of the entire project into a single, huge post, I've decided to split it into multiple parts. The next installment will cover the Mechanical & Electrical parts of the project: removing the original guts of the marquee, and installing the replacement electrical components. Lastly, possibly in a separate post (I'll decide once I've written it), I'll cover the software that brings the project to life.


Stay Tuned!