Help/advice making a backlit box for an acrylic logo?

Everything Else
1

Hi folks! As is a tradition for me, I have had an idea about a thing that I think would look cool, and decided I wanted to make it without any of the necessary skills or background knowledge. I know that it can be done, and I’m hoping some of the Very Clever People here have done something like it before and will be willing to share their knowledge to save me some wrong turns and dead ends.

The Objective

What I’m trying to build is a version of this logo (for personal use, I’m not selling it):

https://reign.overwatchleague.com/sites/reign/files/logo/OWL_AtlantaReign_Logo_Primary_LTGRAY-2.svg

…except that I want the red portions of the logo to have a backlit glow to them. I’m thinking something roughly in the 8"x10" size range, but have some flexibility there.

The Easy Bit

I’m planning to use a sheet of opaque white acrylic with the black/red logo elements cut out and inlaid with black/translucent red acrylic in their place. I’m hoping I can glue those in on the edges cleanly; if not, I may need to use a thin piece of transparent acrylic as a backing board. This thread gives me some good guidance on the adhesives to use, and I’ve done this kind of inlay stuff before, so this part doesn’t worry me.

The Complicated Bit(s)

Once I have a sheet of acrylic that looks like the logo, I need to get it backlit. It seems to my uninformed self that this would just be a matter of getting an appropriately-sized shadowbox , putting some LED strips and batteries in the back, and putting the acrylic sheet in place of the front glass. However, since I have no significant electrical experience other than installing the occasional ceiling fan, I have questions.

  • Does that seem like a sensible way to do this? Is there something simpler/more practical/more reliable that I’m overlooking, or am I oversimplifying things?

  • Are there heat concerns? I know LEDs run pretty cool, but if they’re on for extended periods in a wooden box, am I going to burn something down? Any ways to avoid such risks?

  • How/where could I install an on/off switch? (Yes, it’s that basic.) I know there are a lot of options, but again, I don’t have any real electrical knowledge. I haven’t been able to find any good guides to such things on the web, but I may just not be using the correct search terms.

  • Would a corded power supply be easier/safer/more reliable than batteries?

The Optional Upgrade

Assuming I can find ways to get all of the above done without electrocuting myself and/or burning the house down, I’d love to also get some kind of flickery/flame effect going on (since the icon represents a phoenix). A few things I’ve considered:

  • Instead of solid red, I could use something like a marbled or tortoise-shell acrylic. Unfortunately, I haven’t been able to find a source for that in red yet…anyone know of one?

  • Flickering LEDs would be fantastic. Something like this seems like it might be a good choice; anyone have experience/warnings/alternatives?

The Summary

As you’ve probably figured out by now, I have what I think is a cool idea with almost none of the relevant skills to make it happen. Any advice you could provide would be helpful, from “Hey, here’s a website that provides a lot of useful information for LED noobs” to “You can buy a prebuilt/custom lightbox from these people” to “You are nowhere near ready for this, give it up.” I am definitely willing to put in the time, research, and effort to make this thing work; I’m just hoping to get some pointers from those who have gone before so I don’t have to waste too much time, research, and effort going down the wrong paths.

Thank you!

2 Likes
2
  • Yes it’s sensible, and it’s dead simple. See way below.
  • No, heat won’t be an issue.
  • Wait for it…
  • To get any significant brightness for a decent duration, a cord is the way to go.
  • Try estreetplastics and johnson plastics. Search the forum for “acrylic source”. Whole other topic.
  • Waaaait forrrr iiiiiit…

LEDs are dumb easy, try an amazon search for “led strip remote control”.

The first result:
https://www.amazon.com/Changing-Nexlux-Flexible-Decoration-Controller/dp/B078S48ZTY?ref_=fsclp_pl_dp_1

Tahdah, one step and you’re done with all the electrical bits, with way more features than you wanted. It may have a candle mode. You’ll probably want to hunt around to find the exact strip you want. I like strips that are RF remote and (hopefully) individually addressed, myself.

Let’s see. Ah, here’s one with an RF remote:
https://www.amazon.com/Nexlux-Waterproof-Flexible-Decoration-Controller/dp/B06XC9WJ8W/ref=sr_1_3?keywords=led+strip+rf+remote&qid=1555077569&s=gateway&sr=8-3

RF remotes are nice, because you don’t need line of sight.

Anyway, this is more than enough to get you going.

6 Likes
3

Since you are thinking of making it a battery powered, think of safety in terms of a flashlight. Not as big a worry as dealing with mains power.

My favorite way is just by a strip of 5 volt LEDS and solder a USB cable onto it. You only need the two power wires and not the date wires. That way you can use a low power wall wart or a computer. Another way is to get an LED flashlight. There are all kinds of shapes and sizes, including strip ones. You can re-purpose that and have batteries and a circuit that is ready made.

Sound isn’t the best on this one but it gives you the scrounge version.

Here is one that ups your game. Bulk LEDs come in strips that are on a reel. Usually that reel has one connection that will work as a USB connector so you don’t even need to solder.

You can totally start from scratch on this project. It is simple. Lots of topics on this forum and Instructables also has many.

3 Likes
4

@evansd2, thanks so much for the quick and detailed response! I did indeed see a ton of such strips on Amazon, but they all tend to be in the tens of feet, which seems rather like overkill for such a small project. The smaller strips I’ve found tend to be plain white lights, which is Fine I Guess…wait, these longer LED strips can be cut to size? My head a splode. This may indeed be a lot simpler than I thought…thank you!

@marmak3261, USB is an option that hadn’t occurred to me - thanks a lot for the suggestion and the links!

5

You will want to make more!

2 Likes
6

You are not wrong. :slight_smile:

7

So, when evaluating batteries…

LEDs in this class (5050 size RGB [not rgbw]) tend to run at about 60 mA per light at full brightness white. In reality, when color mixing, you end up closer to 25 mA on average. So let’s assume average draw of 25ma per led at say 60 leds per meter, even a small light box you’re looking at 20-30 leds. Lets call that 25.

25 leds x 25 mA = 625 milliamps.

A moderate sized usb battery pack is about 3500 mAh, so some simple math comes into play here.

3500 mAh / 625 mA = about 5.5 hours, but could range immensely between half that and double that… and you may be using more or fewer leds.

Now, this doesn’t take into account the power draw of the remote receiver and the microcontroller, that will affect you a bit.

Of course, you can get battery packs that are ten times as large (and more expensive), and I am glossing over a ton of potential inefficiencies, etc, but basically everything I am not accounting for is going to reduce your lifespan here. It depends on your use case, but 5.5 hours isn’t a ton of runtime to me, especially if you’re making a clock or something. Lightboxes, maybe that’s fine.

Anyway, to recap – here’s a basic way to calculate it:

Battery size in mAh / number of LEDs / 25 mah/led = rough estimate of hours of use.

Cue an electrical engineer on the forum to tell me exactly how wrong I am… but I don’t think I’m that far off in theory.

5 Likes
8

Yeah, it definitely sounds like a corded power supply is the way to go. Thankfully, that appears to be less complicated than I originally thought!

1 Like
9

You might want to look at making your own barrel jack passthrough to make it more elegant than a pigtail cord hanging off the back, but that’s about the only complication to add to this.

Somethng like this would integrate into your frame side or backplane pretty easily:

https://www.amazon.com/DIYhz-Socket-Female-Mounting-Connector/dp/B079D6P26P/ref=sr_1_5?keywords=2.5mm+power+jack&qid=1555081113&s=gateway&sr=8-5

Search for “2.5mm power jack”, there are lots of styles.

2 Likes
10

I don’t want to hijack this thread, but the LED Light Strips interest me, but it’s 16 feet… Isn’t that a bit extreme for a small back lit light? I’m assuming these strips are all one piece? Can they be trimmed down to a more manageable size?

11

If you don’t need the flickering, the easiest solution would be this one:

Light Table，A4 LED Light Box Tracer USB Power LED Artcraft Tracing Light Pad Light Box for Artists Light Board Light for Diamond Painting,Light Box for tracing Appliques
by ryumei

2 Likes
12

I am amazed at how thorough and detailed your responses are. You really are generous with your knoweldge. And I avoid anything that makes me calculate electronics. That’s why I go with the USB cables. The batteries can last well, but once you start adding on more lights, they go quickly.

Yes, you can cut them in lengths. Some are sets that you can do singles, but some are set to do three for the complete circuit. Usually the two ends are finished and they come with some type of connector cord.

4 Likes
13

@cynd11: Interesting thought. I’m not sure how bright that would be - I know they’re great for paper, but less sure about acrylic. But my girlfriend has a similar one, so it’s at least worth a test. Thanks for the suggestion!

14

I’ve done lots of various things with LEDs and since you can cut them into smaller lengths, don’t worry…as someone already pointed out…you’ll want to use them a lot more.

Only picking out this one part that you mentioned…I found a gorgeous piece of tortoise shell acrylic from Inventables;

https://www.inventables.com/technologies/tortoise-shell-acrylic

4 Likes
15

@Xabbess - yes, that’s exactly the piece I had in mind. My only problem with it is that it’s pretty brown rather than the desired red, which will (I think) be very noticeable in a design with just three stark colors. I’m certainly going to give it a try, though; if the LEDs can be red enough, it may still work. Thanks for the suggestion!

1 Like
16

Last year I bought a large piece of this tortoise shell acrylic from Inventables and I have most of it still. If you want me to send you a sample square of it so you can test before you purchase, send me your information privately and I’ll drop it in the mail.

3 Likes
17

@dklgood: Much appreciated, but I actually already have a piece - when I saw it on the Inventables site, I knew I’d eventually find something cool to do with it. That’s why I’m pretty confident that the color won’t be right…but again, it’s worth a try. Many thanks for the offer!

18

You could always try to paint your own faux tortoise shell finish (lots of videos on YouTube) on the clear acrylic using alcohol inks. You’d probably have to seal it with a spray sealer.

2 Likes
19

Interesting…but that sounds like a lot of work. :slight_smile:

20

These are super easy, if you just need lighting in one spot:

Just plug in to a USB extension cable, and you’re good to go.

Things to know:

  • They do get hot to the touch, but as long as nothing’s directly touching them, nothing’s going to melt or burn.

  • They are touch-on, touch-off, so you need to be able to stick a finger through to the backside of the circuit board to operate them

  • If you touch and hold, you can dim/brighten the output

5 Likes