Tag Archive for 'tlc5940'

Glowscape – An Experiment with Glowstick Dye

It’s been like forever since I’ve blogged. Sadness. Here’s something cool though. 🙂

A while back, I bought an absurd amount of glowsticks for a few bucks on Woot.com. I was wondering what I could do with some of them.

One idea I had was to make some kind of art thing or whatever. After a little preliminary investigation, I discovered that the glass vials in the glowsticks were full of the fluorescent dye that can also be activated by ultraviolet light. So I decided to test it out.

Basically, I just taped a UV LED to the bottom of the glass vial that normally goes in the glowstick. It actually looks not bad. I set up a quick demo with some UV LEDs. Hmm… what could I do?

Maybe a VU meter for sound? Yeah, that might work. 🙂

So, I grabbed 16 red, orange, yellow, and green glowsticks and headed over to MITERS to get to work.

The first step was to sand down the LEDs so they were flat. First they got the bandsaw treatment, followed by some more gentle loving with fine-grained sandpaper.

Hell yeah. All right, time to cut the glowsticks open and extract the glass vials.

So the other stuff left in the plastic part of the glowsticks is high concentration hydrogen peroxide. I decided to save it in a bottle. The concentration is so high that it’s actually very sludgy.

Next step was to sand down the end of the glass vials to make them as flat as possible. Then, I used duct tape to hold them against the UV LEDs.

All right. So then, I ended up letting the project sit for several weeks because I got super busy at the start of the semester. I also had to layout a PCB for the design I wanted. Essentially, my plan was to make something compatible with ACRIS but also provide a standalone mode so that it can independently analyze music.

But, I didn’t want to pay people to produce a board. I wanted to do my own etching. Previously, doing this was extremely difficult because MITERS didn’t have the right tools to do it.

To refresh your mind, etching goes like this. First, print out the PCB layout onto photo paper with a laser printer. Then, use a heat source to transfer that laser printer toner onto sanded copper-clad board. Next, throw that board in PCB etchant and wait for the copper you don’t want to disappear.

But it’s never that simple. The real problem is the transfer. My awesome girlfriend Jordan used a clothes iron to perform the transfer. This method is incredibly unreliable. It’s really hard to get right and every time I’ve done it, I’ve always lost huge portions of the transfer. Jordan made several boards and the later ones she built looked absolutely spectacular — she figured out the exact amount of ironing time and pressure. I’ve tried to do this too, but I’ve never been able to get it right.

But I got to bypass all that because MITERS recently bought a laminator. Laminators provide an even amount of heat across the board with relatively little pressure, so they transfer the toner perfectly every time. Check this out:

The other awesome thing is that MITERS found some new paper that’s really perfect. Usually, it is recommended that you use glossy photo paper. But, a lot of photo paper is very plastic-y. So, when you iron it, the plastic actually forms a boundary so that when you try to wash off the paper after the transfer, it never gets soaked. This new paper isn’t photo paper — it’s just regular glossy printer paper. And it works perfectly because it washes off really easily.

Another thing is that I made the traces really thick because I didn’t want to take any chances. You can’t really do very complicated boards this way. In the future, I’m going to

Next step was to throw it in the etchant. MITERS reuses etchant a lot, so in combination with an agitator, the etching time was about 30 minutes total. It’s important to constantly check it because you don’t want to etch longer than you have to — otherwise you may etch underneath the toner.


Okay. Time for drilling. This one is really hard. It’s very difficult to drill small holes through fiberglass — you can easily blow through a pack of bits if you don’t know what you’re doing. MITERS has this cute little drillpress that I forgot to take a picture of. But it does a great job of drilling stably so that the bit doesn’t break.

Okay, time for board assembly.

Ugly jumpers are ugly. 🙁

My first idea was to align the tops of all the tops of the glowstick vials.

Then I didn’t like the lead spacing at the bottom, so I put it back.

On the first power-up, one of the UV LEDs blew out. Not sure why — I think the quality control on these LEDs is kind of bad.

IDK, it’s not as bright as I would have liked, but I’m trying to figure out what I can do about that. Here’s a video of it just doing a simple chaser effect:

Schematics and board layouts are available on the project page.