I wrote this up as a post on my blog Apathetic Thursday a few years ago, always meaning to get around to making a tutorial for instructables, but never got around to it. Until now. 

This is a 2ft by 4ft back-lit sign, made to look like the Portal video game. (You probably already gathered that.)

The entire project came in under $200 for me. The biggest cost is going to be your sheet of glass or plastic for the front. I used white glass from a local stained glass shop. 2ft x 4ft was the largest size it came in. If I was going to do this again, I might try to use a white plexiglass or plastic, but I think that was actually more expensive at the time.

Even lighting is probably going to be the most difficult thing to achieve. In the photographs the sign looks very evenly lit, it is less so in real life. (Some of the other pictures show this better. I used two off the shelf light fixtures that had circular fluorescent tube lights. I might look for something different if I were to try again. Maybe this? ("2-D shaped" light bulb.)

One final note: I'm going to talk you through my process for making my light. If you want to make your own there are several dependency routes which you can follow. By this I mean: If you choose your size first, that will determine the panel material, which may determine the lights you can use. If you choose your lights first, that may dictate the size of the sign and therefore what panel materials will work. Finally, if you choose panel material first, that will determine your size and probably your available lights as well.

Okay, on to the materials. I'll list the main ones here quickly and go into more detail on the next pages.

2 ft bx 4 ft sheet of white glass ~ $60
Clear Adhesive Film ~ $10
(I used Grafix Ink Jet Adhesive Film from Amazon.)
Adhesive backed Black Vinyl ~ $10
(Again, from Amazon I got Cricut Vinyl)

Fluorescent Light Fixture of some sort.
I used a GE circular fluorescent light fixture from Menards.

1x4 boards, of various lengths (2x 4ft, 5x ~2ft)

Wall plug and cord
Aluminium foil or other reflective material

Black Paint
Sand Paper

Exacto Knife
Straight Edge
Cutting Board
Table Saw

Total Cost: ~$200, if you don't have to buy the tools.

Step 1: Research and Planning

First step is to figure out what size you want to build. If you want to go larger than 2ft x 4ft, you may have some problems finding glass, plexiglass, or plastic for the front. You could easily go smaller.

The first thing I did was grab a screenshot from Portal 2. I estimated the lines in the game to be 1ft apart. They are probably more than that, but this gave me a grid to work off of.

The sign is 2 times taller than it is wide.

Using a printout and some lined paper I measured out all the dimensions and converted them to inches and feet for my own sign.

I used this data to estimate the size and quantity of the adhesive vinyl I would need.

Step 2: Finding the Glass

Choosing the material for the front panel will dictate many other things about your final product.

Personally I would recommend white glass, especially if you are going for anything smaller than 2ft by 4 ft. Anything larger probably needs plastic of sorts.

This is partly due to the brittleness of the material, but also due to weight. My sign weighs a fair amount and hanging it can be tricky.

Again, I used white stained glass, though I did experiment with using clear glass with a coat of white paint. This did not look great, but you might be able to find some sort of frosted glass which works as well.

The size of your front panel will also effect the type of lights you can use to light up the sign. Since mine was exactly 2ft by 4ft I didn't think I would have room to use full length fluorescent bulbs like I originally planned. If you want to use 

Step 3: Decorating the Sign

The designs of the lines and numbers are made up of adhesive backed vinyl which were cut out and placed on the glass. The more intricate symbols and logos were printed onto the clear adhesive film.

Ensuring that the lines were straight was a priority for me. To achieve this I actually used some (red) electrical tape to help space things out.

The vinyl had a grid on the back so straight lines were easy. I measured the corners and did them by hand so they matched the screenshots from the game.

I then hunted through the Portal Wiki to find the chamber info icons I wanted to use on my sign. You can choose any of them you like (or make your own.) I picked which ones were greyed out and which were black and printed them on the clear adhesive so I could stick them on the glass. 

A few notes on the clear adhesive for the  icons and the logo:

Make sure the printer you use is printing in black and white. Even though the image you are printing is black and white, the printer might use trace amounts of other colors in the print. My Aperture Logo came out a little blue/purple-ish when I printed it. Especially when light is shown through it.

The image can be scrapped off the clear adhesive. If you are not careful you can scratch the image off with your fingernail or by frictional contact. You might want to keep out of reach of children. There might be a better way to print these off, but if you use the clear adhesive you may need to treat it gently.

Step 4: The Frame

I made my frame out of 1x4's. I knew my sheet of glass was exactly 24 inches by 48 inches. I planned to have my frame hold the glass in place with a small groove that was about 1/4th an inch deep. I used a table saw to cut the slit in all the pieces of my frame. 

(I actually cut it on both sides, it turned out that wasn't completely necessary, but it was helpful.

I then measured out the correct length for the top and side pieces which had to take into account a 1/4 inch slit on both ends as well as a 45 degree angle cut.

Due to the weight and fragility of the glass pannel, I didn't feel my frame was sturdy enough yet, so I added some braces along the top, bottom, and middle of the back.

You'll also note, I did not put the bottom of the frame on yet. I needed to slide my glass in before I closed it up.

I then gave it a coat of black paint, being careful not to fill my grooves with paint.

Step 5: Back Panel and Lights

Since the glass panel on the front was going to be screwed in place, the back needed to be accessible to replace lights or do other repairs as needed. For this, I just put two panels on the back and hinged them to the middle brace.

I had some 1/4 inch plastic sheets at my disposal, but some thin sheets of wood would also work.

Since I had a groove on both sides of my frame I used some thin wood to act as swinging locks to hold the panel closed. Slide them out of the groove and it would easily open up.

I attached the light fixtures I had bought to the panels in strategic locations so that the lights would fit nicely and the lighting would be fairly even throughout the inner section.

I also covered the inside with aluminium foil to help reflect everything and nicely and evenly as possible. It did make a noticeable difference.

I fed the cord for the electric plug out a small hole I chiseled in the bottom of the frame.

Step 6: Inserting the Glass

Now that I had everything in place and painted, I could insert the glass. We lined up the glass in the grooves and slid it in...

But it was too tight. There was a small section of the frame which was not as wide as the rest. Using a drill and some sand paper we managed to carefully widen the groove I had made so that the glass fit snuggly, but not too tight.

This is a very critical point if you are working with glass. It should go without saying, but I'm going to say it anyway. The glass is fragile. You do not want it to be too lose so it might wobble around and break, but you don't want it to be too tight either. Forcing the glass into a space that is too small could cause the glass to break as well. The extra tension could shorten the lifespan of the sign.

If things are too loose you might want to find some way to help keep the glass from moving around. Some scraps of felt or foam could possibly work well here.

Once you get everything in place you may want to test it out before you put the final cap on.

I made sure it all worked, then screwed the bottom into place, added my wood filler to the holes and did some touch up painting.

Step 7: Congratulations!

You have a Portal Test Chamber Information Sign!

As you can see, it is a little obvious where my lights are and are not inside my sign, but the overall effect is exactly what I wanted to achieve.

I leave mine on 24/7 as a night light in my dining room. If you want you could easily add a switch to yours to make it turn on and off more easily than unplugging it. This also might be fun to put on a motion sensor so anytime you came into the room it would auto light up.

This tutorial is really rather open and purposefully so. There's no one right and correct way to make the sign and it really all comes down to what size you want to create. I have been thinking about making a smaller 1ft x 2ft version which would work better and be less obtrusive.

My main goal is to show my materials and the process so that you can experiment on your own. This is APERTURE SCIENCE... WE MUST KEEP TESTING!
<p>Hi, I know its been a few years since you've done this but I have a question.</p><p>what are the dimensions of the chamber info icons you have on your sign. I know they're squared but what size are they? </p>
Hi, one question. How did you make the actual picture of the sign? Thanks.
<p>Hey, I'm not entirely sure what you're asking about. Are you able to clarify?</p>
I think LED are the way to go but I still think there will be hot-spots. I ran into this exact problem when trying to make a backlit whiteboard. What I want to try is using the same material they use for ping-pong balls. Ping-pong balls seem to diffuse light very evenly as long as the light is in the center. For big money you could always go with something like this: http://www.lighttape.com/
And please....anyone...if you have figured out a way to evenly back-light a glass surface without adding a ton of depth...post!
If I were you, I might try adding a diffuser between your glass &quot;display&quot; part and the lights. A piece of frosted glass or plexiglass (or several pieces butted up to each other, to fill) perhaps. <br> <br>That, or as some other people have suggested, preventing light from directly shining from the bulbs to the display (throwing a layer of foil on top of the bulbs) might help some, or using lots of leds to make a close to uniform lighting source. <br> <br>That being said, I love what you've done!
I am pretty sure that the LED strips would be the best way to do the even lighting, provided that the LEDs are several inches away from the glass and evenly spaced (a few inches apart) it would probably work pretty well. <br> <br>That said... it's all about the TESTING... there is Science to be done here!
To see how the pros do it, rip apart a dead laptop LCD panel. They use a strip of LEDs (or a super thin fluorescent tube in older models) along one edge. This shines into a tapered sheet of acrylic with almost a stepped taper, so the light gets refracted out the front of the screen as it progresses. On top of that they use several whackado frenal lenses, which don't so much magnify as split the image into two, topped off with a frosty looking diffuser to finish the job. <br> <br>It could be tricky to find these components separately, but I'll bet if you could find a dead LED/LCD TV (even one with a cracked panel) they'd probably use a similar setup. Even if you had to combine a bunch of them to get a suitable size, it should make too much of an issue at the seams.
This is very well done. I can see from your photo as you stare at the sign that you are imagining being in &quot;Portal&quot; for real. <br> <br>Anyway, LEDs in an array behind a diffuser would solve the light and dark spots issue. It would also be more energy efficient and not require bulb replacement. It would, however, require a power supply design, but that would not be difficult.
Thanks for the comment. I've had a few people suggest different light upgrades. I'm actually kinda thinking about doing an LED upgrade, though it may be awhile before I get around to it. The power supply is what &quot;scares&quot; me, but I have no doubt I could find a good instructable to show me what I need to find/do.
Consider a string of LED X-mas lights--all the work has been done. Depending on how they are made, you will want to experiment. The cones of light emitted by each lamp need to overlap slightly so that the diffuser can blend them into a seamless light panel.<br><br>Have fun and just wait until one of the bulbs burns out for motivation to upgrade to LEDs ;-)
Go on Amazon and order led strip lights. They come in 5 meter rolls and you can link them end to end so long as the power supply is sufficient and the string current isn't too high. <br>Space them out as rows or columns evenly. And you will get even coverage all over. <br> <br>Here's an example of the same idea for a photography light: http://instructables.com/id/Led-Light-panel-kit-for-photography/
Thanks for the link. Thats certainly wasn't something I was thinking about when I made it. If/when the bulbs die though, I may upgrade my design.
This is awesome!
I have no experience with glass, but why dont you slide it from the top? That way you can ensure the bottom bit, the one that holds most of the weight of the glass, is perfectly fit into place.
I was planning to screw and glue all the sides of my frame together, so ultimately it didn't matter which side was up/down. That said, if you want to be able to slide the glass in and out (maybe use that as your access panel to the back for changing the lights when needed) that would totally be a good idea.
Being able to change the glass from the top would be a great idea if it cracked, or if you made a bunch of different test chamber panels and wanted to switch them up. :)
I imagine it would be best to make a screen that can be programmed to display different information, although this is nonetheless a great instructable.
Very cool! Just thinking out loud here about the even lighting problem you mentioned. What if you chose to reflect the light off of a reflective back (Al foil maybe to be cheap) and shielded any light from directly reaching the front panel. You see this in overhead lights a lot with the fluorescent tubes tucked along the frame (on all 4 sides) and then a lip prevents them from shining out the front and instead the light reflects off a mirror in the back. By mirror, I mean any reflective surface. You usually see it being a polished metal but I think aluminum foil would work well if flattened smoothly. I see you already use the reflective backing, but I am suggesting ONLY using those reflections... thoughts? <br> <br>Definitely gonna make this at some point! The glass is the hard part for me to find.
He is actually using reflective foil, as can be seen in the pictures. He just didn't shield the lights.
Just another thought, apply glass etchant to the entirety of the backside of the glass. I don't know how will that would diffuse the light, but it would certainly help.<br><br>Either way, totally awesome build.
That would certainly be an option. I think part of my &quot;problem&quot; is that the sign was too shallow, so the lights had to be too close to the glass. If I went with 1x6 boards rather than 1/4, or found lights that were smaller width and could be an inch or two farther from the glass it would look a lot more even. The other option might be to add a second layer of diffusion, though I don't have any good ideas on how, right off hand. <br> <br>If even lighting is a concern, I would totally recommend starting with your lights and frame and worry about the glass or plexiglass at a later time. <br> <br>Glass can be hard to find/obtain. I had to drive to a nearby town to find my source.
This is by far one of the coolest builds I've seen. I may have to give it a try this summer
Awesome! Be sure to post your process (or at least your photos.) Love to see how yours turns out.
And great pictures, they are nice and focused.
Simply amazing.
Man, I could probably stare at that all day if I had one... just like it looks like you were doing.
Very Nice, I salute you.
Very beautiful!

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