The backstory: I sleep earlier than all my roommates, as I wake up with the sun (and 3 hungry cats). I want my roommates to know when I'm sleeping so that they are more aware of their own volume. I made a "Shh.. Sleeping" door hanger in my last instructable, but that just wasn't visible enough at night.

So for my next attempt at passive aggressive nighttime communication, I've made a backlit "Shh... Human Sleeping" sign that looks like a pretty wall hanging during the day. Keep reading to learn how I made it!

Step 1: The Supplies & Tools

Here are the supplies you'll need:

Shadow box frame, like the Ikea 9x9 or similar from Michaels. You can also go bigger with this 12x12 from Amazon.
Decorative fabric. This will cover the sign so it's pretty during the day.
Birch plywood or cast acrylic, to cut in a laser cutter. 1/8" or even thinner. (If you don't have a laser cutter, it may work to cut the sign out of cardstock or paint it on the glass directly.)
(Optional) Diffusion layer. You can either frost the glass that comes with the frame using frosting spray, or you can laser cut a piece of frosted acrylic.
LED strip, like this 12V Warm White non-waterproof strip. If your strip is 5V, make sure the rest of your supplies are also 5V.
Female jack connector. The strip comes with one at the end, so you don't need extras if you're only making one sign. I find myself making backlit signs all over the place now, so I bought a bag of them.
Power supply,wall plug or brick. 12V, at least 2A output.
(Optional) On/off switch. It's easier to press a switch than unplug it each night. :)
(Optional) Dimmer. 12V, only works if your LED strip is dimmable. You don't need a switch if you get a dimmer.
(Optional) Extension cable. Handy if your outlets are far away.

Here are the tools you'll need:

Laser cutter, like at TechShop SF.
Soldering iron, heat wrap, heat gun.
X-acto knife, cutting mat.
Sanding paper or sponge.
E6000 glue.

Step 2: Laser Cut the Sign

Download the AI files from my Thingiverse. The file has two options, a version that has a simple sleeping face and a version that's just the text, as shown. The sleeping face is cute, but I decided it was more important that my text be highly readable.

If you make your own sign, make sure that you modify the letters so that their middles don't fall out (Eek!). You can see how I modified the e, a, g, and p in my sign.

Cut the sign on either wood or opaque acrylic, no thicker than 1/8" to make sure everything fits in the frame.

You can finish the sign with sanding and stain if you'd like, but if you plan to cover it in fabric like I did, then you don't need to do anything to it after cutting. Yay!

Step 3: Make Diffusion Layer

You have a few options for the diffusion layer, which will make the LED glow softer. You can even leave it out entirely, and skip to the next step now.

One option is to frost the piece of glass that most likely came with your frame, using Krylon frosting spray paint. Coat it about 3-4 times.

Another option is to purchase a thin piece of frosted acrylic, either already cut to the size of the frame, or cut it yourself with the laser cutter. If it's dirty, you can clean it with a microfiber cloth and plastic cleaning solution.

Step 4: Cut the LED Strip

Take the inner frame out of the shadow box frame. Cut an LED strip to fit about 90% of the way around the inside of the inner frame.

Step 5: Solder the LED Strip

If you're using the end of the LED strip that already has a jack connector attached, you can skip this step.

Solder the LED strip to a female DC jack connector and use a heat gun or lighter to melt heat wrap around the soldered connection.

Step 6: Test the LED Strip

Attach the strip to the power plug and plug it all in to confirm that the LED strip works. Yay, pretty LEDs!

Step 7: Sand the Inner Frame

Sand the inner edges of the inner frame, using coarse grit sanding paper or sponge. It makes it much easier to get the LED strip adhesive to stick, trust me.

Step 8: Adhere the LED Strip

Line the inner frame with the LED strip, pressing the adhesive down. It’s best to end the LED strip in the middle of a side, so that it can easily come out of the backing and hang down the bottom of the frame.

Step 9: Glue the LED Strip

To be doubly sure it sticks, coat the strip with E6000 glue as well, particularly the corners and the beginning of the strip. The cord hanging off will try to get the strip to come up, so you just have to convince it with E6000 that it doesn't want to do that.

You can use binder clips to clamp it down while it dries. Or real clamps, if you're legit like that. :)

Step 10: White-out the Backing

Whatever frame you're using, it should have a backing piece that hangs on the wall somehow. The IKEA frame has a brown colored backing, which doesn't work as well as a white backing.

Find a way to make your backing white. I tried both painting it white and attaching glossy printer paper with double-sided tape, and I found the latter technique much faster and splotchy-proof.

Step 11: Cut a Hole for the Cord

Now you'll need a hole for the cable to come out of the backing.

Put the backing on top of the inner frame to see where the connector comes out and lays flat. Make sure it isn't visible through your sign's letters. Mark that location, and use an X-acto knife to cut out a mouse hole for it.

Step 12: Assemble the Naked Frame

Now you'll do your first assemble of the frame:

Wood/plastic sign
Frosted glass/plastic
Inner frame
Cardboard backing
Power supply

Does everything fit? Does it work? Awesome!

At this point, you might decide that you're done, if you're not adding a fabric layer on top. I used these same steps to make signs of Tibetan sanskrit letters that look beautiful with and without illumination.

If you are covering your sign with fabric, however, please continue.

Step 13: Pick Your Fabric

The goal of this step is to find a piece of fabric that will look opaque during the day, but that will let enough light through so that the sign is readable at night.

Fortunately, I live next door to a mum with ample fabric scraps, so I got to try out many options. What I found:

Gauze works, but only when layered about 4 times.
Printed fabric doesn't work so well, as dark print masks the illumination fairly significantly.
White fabric is too transparent.
The best fabric I found was an upholstery scrap with white and yellow thread. Parts were double backed, but I managed to cut a scrap around them.

It helps if you can text out fabric by actually laying it on top of the frame. If you need to go the fabric store for fabric, then perhaps you can battery power your LED strip at the store, or just use your best judgment.

Once I found that piece of fabric, I cut out enough to fit the frame plus a 1" margin on the sides, to give me room for wrapping it around the frame.

Step 14: Adhere the Fabric

Now you need to adhere the fabric to your sign somehow.

My original hope was to use a staple gun, but the staples were too long for the wood piece. Instead, I used duct tape to adhere it on the top and bottom, and then after it was up for a few days and I was still liking it, I used Tacky glue to adhere it permanently.

If you don't find a good fabric scrap for this part, you could also try making a water color painting on heavy sketch paper. I haven't tried that personally, but it seems like it would be opaque enough to hide the shape behind but transparent enough to let light through.