So my LED mermaid tail is turning into a bit of a nightmare to

So my LED mermaid tail is turning into a bit of a nightmare to keep running, and I’m tearing part of it down and revisiting my strategies – basically starting on rev 2. I’ve been using Adafruit Neopixels exclusively so far, but I am thinking now I want to add in some WS2801 LEDs since I found some in a very robust (and waterproof) format.

Will it be possible to run the same code on the neopixels and the WS2801 LEDs at the same time? Or is this going to turn into a nightmare? I know I’ll need to hook up a clock pin, but are there any other issues I can anticipate if I go this route?

FastLED makes it very easy to run multiple strips at the same time – even if they’re different pixel/chip types. You call “FastLED.addLeds()” once for each string of LEDs, specifying the chip type for each string when you ‘add’ it, and that’s pretty much it. After that, when you call ‘’, it’ll update all of them at once.

There are more complicated options available, too, but the simple case is very easy to get going.

ooh I was hoping that’s what you were going to say. Thanks!

Sweet to know!

@Erin_St_Blaine , what kind of “nightmares” are you running in to?

The biggest issue is that the fluke is huge, heavy, and very very delicate. The ocean doesn’t really promote super careful gentle movement … So the light strips around the edges keep breaking and I have to cut into the silicone casts to resolder the lights, and then try to re-waterproof the whole thing. And then, inevitably, water gets in. Aargh.

For this second rev I have cut the fin down to about half the original size, so it’s lighter and more manageable, and I’m going to try a different approach with the LEDs. The neopixel light strips are just way too delicate.

I’m sad – I loved the look of the long elegant fins – but I’m taking the tail on a couple photo shoots in the Caribbean this summer and I need it robust and reliable. (I want to spend my down time in the bahamas drinking rum, not soldering!)

So I’m wondering: are you using strips that are molded in silicon, or are they sleeved? I’ve discovered that the molded ones get brittle when cooled - I took one outside when it was around 40 degrees and they turned hard and brittle and started cracking almost instantly. Since then I’ve started using the sleeved ones and they do much better with cold temperatures.

I was using adafruit’s weatherproof strips, without the included silicon sleeve. I made a custom silicon dragonskin mermaid fin thingy that I embedded the strips in.

Hrm, I haven’t had those type break on me (yet) … the molded ones break all the stinking time.

Do you mean these? This is what I am planning to use instead… Would be good to know if that will just be another nightmare…

No, never used those. The ones I use are like the Adafruit ones, they’re sleeved. What I used to use were molded, where the entire upper side of the strip is molded in a semi-hard silicon. No longer use those.

How are they breaking on you? At the joints, or somewhere else? Do you have a picture of one such failure? Just curious.

they’re getting torn along the cut lines between LEDs when the tail flexes. These strips aren’t made to take really ANY sideways torque. I knew that … and I put spacer wires between lights at main the flex points, but that wasn’t nearly good enough. Every time the tail would flop too much or even if someone would pick it up wrong, the strip would tear in another fun and exciting place. Usually fixable, but not without compromising the waterproof silicone.

Oh they’re flexing side-to-side … yeah, that’d be bad for them. You’re better off with the ones that you just linked above, individual pixels with wire connections in between. You’ll just have to attach them close together … one by one.

Oh dear @Ashley_M_Kirchner_No that doesn’t bode well—do you mean you’ve been having trouble with these ones breaking:

(They’re what I’ve bought for my jacket project.They will be running up-down and won’t flex much, but you’ve got me worried now.)

Yes, when they get cold, like it tends to get over here, they get brittle and the coating will break off if you try to flex it (any direction.) I’d you’re lucky it will simply detach from the flex strip, otherwise it will tear the strip as well.

Oh, you’re talking about “proper” cold—so I’ll be fine on the playa.

They get sticky and exhibit melting tendencies when they get hot. I had a roll outside in 85 degrees, and not only did it turn like jelly, but it started sticking to everything. This is why I prefer the sleeves now.

@Erin_St_Blaine I have seen similar pixels outside Adafruit come in IP 65 and IP68. If you’re going to use it underwater I recommend that you confirm these are IP 68 or seal each pixel with silicone. The IP 65 Pixels will allow water in after a few minutes and fail. Pixels rated IP 68 should be completely sealed.
The Adafruit link doesn’t show the IP rating.

The issue isn’t that, the issue is that the seal itself is breaking. If you twist them sideways, they will break, and that’s what’s happening to her.