Halloween Prop - Lighting Questions?

This isn’t truly a “WLED” question, however, I am sure there will be lots of knowledge here to comment on my question(s). I am interested in building a Halloween prop (say 20" x 30") that can take on some of the looks of the Scary Skull at this link Scary Halloween Skull Gift Idea Digital Art by J M
My thought was to create the outline and cutouts from corrugated plastic, but, I am unsure how to go about the lighting. I am not trying to replicate the combination of orange, yellow, red, but more to just have the eyes, nose, mouth sections take on a bright (although single color) vivid display. I am guessing that to do this, I may have to create a light box behind the front panel and to possibly line the back of cutouts with some sort of diffusing material so the raw led pixels deliver a more even/blended color. I would use WLED to vary the colors from say a dim/dull purple and green to a burst of orange/yellow (just ideas at this stage).
I would be interested in any comments or suggestions that you may have on how to build this. I am feeling that I can take care of the WLED part once I figure out how to build it.

A “lightbox” with LEDs mounted to top layer facing in, if that makes sense.

Yes - I am still thinking lightbox. If you have a few minutes to share a bit more:

  • I am thinking this prop would be mounted above eye level (from my eave). Would this change your thoughts of mounting the lights in the top layer?
  • Are you thinking that by placing lights in places not visible through the cutouts, there would be no need for diffusers?
  • I am thinking the inside of the lightbox would be white - better light reflection and easy to get. Thoughts??
  • If you are aware of something that might be similar - could you provide a link
    Thanks - don’t mean to punish you with all this extra just because you provided an initial response.

I meant top when sitting flat on a table.

Hello to you both ,

Since we have seen your house already then you must go over the top , so is a big matrix out of the question ? !!!

I just got a very good deal on five 16x16 matrices for less then 50$ . I would see just do it so the neighbors will be happy and for sure it will be sick for Halloween

@tonyno - thanks - I did misunderstand your original response. I was in a paradigm of thinking 12mm pixels as that is what I am using in the rest of my plan. One (hopefully) last question - were you thinking sections of led strip (say 60 per m or greater) or other products?
@aldy - I do appreciate your “go big” responses. You have given me something to think about for other (affordable and hobby) experiments. One question though - how do you power these - the ones I looked at suggest they still need the .3w per pixel, suggesting that at 5v, a 7"x7" panel could draw up to 25 amps. Do I have this wrong?

One quick (hopefully last) post here:
First - sorry @Aldiy for getting your username spelled wrong in my last post.
Second - I assume that using led string pixels, led strip pixels, etc. can be used in the same data link as long as they all use the 2811 protocol and all voltage levels are kept the same or at least care is taken to keep the grounds (negatives) the same. Comments???

Hi ,

The normal WS2812B is rated 9watt per 30 leds so its the normal 600 mA per pixel ( I do not believe this anymore as in practice we need way less power )

Also those matrices are WS2812B ECO which means they draw even less power . I have two for last few months and what i noticed is they really need little power ( not on full brightness of course ) .For two matrices connected to the same PSU i needed around 2 A for the 512 pixel , the other five are still on route from china . I think the 5A PSU will be fine for me .

ALDY :slight_smile:

I expect you’ve missed a decimal point here and meant 60mA/pixel = .06A/pixel…

The best way to get “real” numbers on this is to setup a small test with 10LED’s at full brightness and full White and physically measure the current draw of the strip with a meter. Divide that number by 10 and you’ll get your worst case current draw for 1 LED. Always better to get real numbers than rely on unknown guestimat… er… specifications.

Just make sure they are all the same color order. :wink: You don’t want RGB and GRB on one data run, for example.

Yes it is 60mA for WS2812B but the matrix is WS2812B ECO which is even less .
I get my power reading from a usb tester connected between the leds and PSU .

Once I get my 5 matrices I can bet I will be able to power the 6x512= 3072 pixel from 8 A PSU.
I will only do this once I get my fuses :fire:

Also sorry to hijack the post , please lets not forget TOG99 question or he will not be happy


Thanks each to the great info. Yes - I was concerned about the RGB vs other sequences. Because I would use segments, I “may” be able to compensate by selecting colors different than what I want displayed. Better yet though - as you suggest - I will try to find a product compatible with what I am using for pixel strings.
I am also a believer that we do not “always” need to use power supplies rated for max published loads… I will keep the info you offered in mind if I chose to acquire some matrices.
Your info has given me some new ideas to pursue for my small project - I am happy.

Just to be clear. Maybe you would only need two sections…



@tonyno - this is awesome - thank you. In principal this is where I was heading with this. Because I am thinking of cutting out the skull shape, I envisioned the two strips running horizontal with one just above the eyes (and just below the ears) and one just under the nose from corner to corner of the mouth. I was also thinking of a small 3’rd portion (maybe just above the upper horizontal). Because, I would like to end up with a sequence of low intensity purple/green with intermittent spells of high intensity orange/yellow - I didn’t feel I had the skill to create this in the same strips so I would resort to each effect having it’s own segment. My plan does mean I will have to use some creativity with building the sides of the box.

I am needing to purchase some 5 volt strip lights. The string lights I am connecting to have a color order of RGB. In searching strips I find that so many of the listings do not specify what order their product uses. I have found that BTF and Alitove do at least specify, however, it is GRB (same as my 12 volt strips).

Does anyone know if there is a light strip product using RGB?

If your controller has multiple data pins you can use (2 or more), you don’t need to worry as much about the individual strips as far as RGB/GRB 5V vs 12V, etc.

In WLED if you have 2 (or more) data pins, they can drive different types (RGB vs GRB) as set in the LED preferences but they will appear as one long strip when you go to create presets and segments. You set the type, length and GPIO pin of each strip in preferences and WLED does any colour conversions needed on the fly for you.

As far as physical hookup you connect the power lines to both strips and add a separate data/ground line from each GPIO pin to the two strips.

So two physical strips of 45 LED’s just becomes one segment of 90 when you’re choosing colours. You can apply a colour or effect to the whole strip or just pieces as you require. It ends up working the same as one long strip as far as you’re concerned.

I am using a Dig-Uno controller. Is this a place where I could use it’s second Data Out?

Do you have the 8266 or the ESP32 version?

I don’t have a Dig-Uno myself, but from what I quickly read on the specs it looks like the ESP32 version makes it pretty easy to get a 2nd strip going.
Either chip has extra pins available, it’s just the way that board has been setup to let you connect the outputs.

I do have the ESP32 version and it does have a D1 and D2 already wired to mounted terminal strips. I suspect with a little hunting, I will find an example of how to put the D2 terminal into use.

No need to go far. Check Quindor’s site. :wink: