This is part 2 of a ‘however many parts it takes’ series on an LED installation we’re doing for a nightclub on Railroad Square in Santa Rosa. Check out my previous installment, or go read the series.

So, Caleb ordered 15 five-meter strips of APA102 IP67 sleeved LEDs. APA102’s are relatively new, and straddle the world of addressable LEDs, somewhere between the LPD8806 and the WS2812 in terms of utility and awesomeness. Curiously, they are available only in strips at this point (at least on AliExpress). One little problem with them: Caleb bought IP67 rated strips, which have a silicone sleeve surrounding it. Given the indoor nature of the installation, this sleeving was just going to be a nuisance.

Hey there, little fella.

APA102 freed from it’s IP67 prison. Hey there, little fella.

In short, the sleeving needed to be removed. I ended up figuring out the easiest way for us to do this, after having struggled for an evening to do it all by myself.

In short:

  • Cut around the silicone end caps on each end. Yank them toward the wire connectors.
  • Cut or desolder the wire harness on one end to give a nice strip edge to pull through the sleeve
  • One person holds the other end (with the wire still soldered on), and you hold the sleeve on the end that has had the wire desoldered or cut off
  • Yank. The LED strip will soon be removed from the sleeve.

It is important to note that the silicone they use to seal the ends of the IP67 sleeve will get all over everything, including your hands, your clothes, the wire you’re trying to remove, the LED strip that you’re desoldering, the work surface and the floor. It’s like polystyrene pebbles in its ability to tenaciously stick to everything.

I just said "tenacious". That calls for a celebration.

I just said “tenacious”. That calls for a celebration.

After a long session with Caleb, epic fellow traveler and stone cold killer Lee Clark and myself removing and prepping all of the APA102 strips, we needed to test these things.

Enter the PixelPusher

I’ve never used devices like Heroic Robotics’ PixelPusher before. Whenever I tried to build an LED light (like the time I made a seed starting grow light out of WS2812 LED strips for my wife – yeah, I know… but it was reasonably effective) I used an Arduino running the now largely debunked Adafruit NeoPixel library (complete with tightly timed assembly language routines that are unnecessary to drive these things).

Anyhow, PixelPushers are pretty neat little purpose-built Ethernet-equipped LED drivers. Lots of very excellent LED installations and even some robot experiments have uses these drivers effectively. Color me impressed.

So, we had to get Pixel Pushers configured, bodge together a connector that would connect the strips we had on hand to the device, and provide power to the whole thing. And then we needed to provide something for the LED strips to do in order to test them.

Luckily, we had power supplies (lots of cheap AliExpress 5V 40A supplies) and connectors (we just desoldered them), we now needed to push a signal to the PixelPusher.

And Now, We’re Processing

We turned to Processing, the thing that Arduino’s IDE is made of.

Word to the wise: Processing is NOT the same as Arduino’s IDE. The programs (“sketches”) you make in them are vaguely similar in structure, but the similarity ends there. Trying to debug anything in Processing was a non-starter for me.

The good news was that PixelPusher has a contributed library that is easily downloaded, with several examples. Once we pulled one of those out, we shortly had colors running on the strips.

DAMN. THESE THINGS ARE BRIGHT.

We tested a strip of 150 LEDs, and it was really bright. We’re making an installation that’s going to have 40 times that number.

They might be handing out sunglasses to the folks who enter the VIP room, I’m thinking.

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