Introduction: LED Backlit Sign

Ever need a creative way to ask a girl to prom or some other sort of dance? Well here's a simple project that is visually stunning, creative, flashy, and sure beats asking with a normal poster and chocolates. If you're creative and need to win a girl's heart, this could be the way! Girls, same for you. Impress the guys with this awesome project! 

Not in high school anymore? Well, this project is still right for you! If you need something flashy for your business, something cool for your kids, or just want to build a LED poster, this is right for you. 

So how does this project work?  

It's pretty simple. All you need are some basic soldering skills, tracing/cutting skills, purchasing skills, and some arts/crafts skill. 

I came up with the idea myself. I have not seen anything similar to this project yet. Everything was thought up and assembled in less than one week. 3 days to be exact. (Well one week as in planning/assembly, minus shipping time.) Thanks to help from some awesome friends. 

And if you think this is cool...engineers, I need your help. I have an even more awesome idea...a marriage proposal that will be super kick butt and awesome, yet personal. So...if you know CAD software really well, know how to use laser printers, CNC machines, 3D printers, Mini LED Displays, electronics, circuits, mechanical stuff, maybe woodworking, and or have an artist side and you're willing to help, let me know! Don't worry, the project is still many, many years down the road... Let me know if you're interested! 

Okay, lets get started. Proceed to Step 1. 

Step 1: Materials

The required materials will drain about $60 from your pockets, possibly more or less depending on how many of the supplies you have on hand. For me, I used things that I could find around the house/my school and the rest of the materials were bought in-store and online. 

Materials List:
Poster Board - 20" x 15" (10 pieces) 
LED Strip - 5M RGB LED Strip with controller - I bought mine on for $15
LED Strip Connectors (5cm 4pins Male to Female extension wire for 5050 3528SMD RGB led flexible strip - for $8)
Batteries (You could use a power supply too as long as it can support 12 Volts - I used a battery pack from the solar plane project)
Solder (Just some standard solder) 
PVC Pipe (1/2 in" PVC Pipe - I used around 20' of it 18' to be exact) 
PVC T-Joints (1/2" need 10)
PVC Elbow Joint (1/2" need 2)  
Zip Ties (Normal size- 8" or bigger & the small ones too. Grab a big'll need around 35 big ones and 15 small ones) 
Hot Glue 
Aluminium Tape
Aluminium Foil 
Drop Cloth - Some Wax paper could possibly work for this too- I just had some of this stuff on hand and it's wonderful. 
Empty Towel Roll Tube (You'll be cutting it into 1" tubes) 

PVC Pipe Cutter
Friends (At least one artistic friend, and a bunch of close friends willing to help you) 
Digital Multi-meter
Wire Stripper

Step 2: Front Board

The front poster is the side with the words. All that needs to be done with this board is cutting out the letters and gluing the drop cloth on the side facing inside. 

The LEDs are basically sandwiched between the two posters so the "front poster" is the one with the words. The rear poster is the one that contains the aluminium foil, LEDs, etc. and is connected to the PVC pipe. 

First you need to make sure all your posters are the same size. 

After that, trace a .5" border around each of the front poster boards on the out facing side. These guide marks serve as a guide for laying out the Aluminium tape border. This adds on to the aesthetic appeal of the posters. 

Then, figure out what font you want to do the words in. I chose to use the font from "Wicked" because the girl I was asking likes that musical. 
Trace the words onto the foam boards via sharpie. For the "O" in "Prom," I put Felix the Cat in the center because the theme for my prom was masquerade, and that is like the Great Gatsby which is from the Roaring '20s, and Felix the Cat was popular during that time. My artist friend was able to help me draw him out with a mask and with the help of my computer, I colored and printed him onto a 8.5 x 11 paper to trace onto the drop cloth. 

Next, cut out the letters with an exacto knife and glue the pre-cut drop cloth tightly against the foam board on the side facing in. Notice that I taped it- that doesn't work as well. Hot Glue works better in this case. For letters that have a center like "P," take the center "island" and glue that onto the drop cloth. 

For Felix the Cat, I traced him with Sharpies. 

Step 3: LED Prep

The LED Strip comes in a 5 meter string of lights. It also comes with the IR Receiver/Power Input device and controller.
To make the LED Strip light up, you need to solder a coaxial DC plug to something with a power supply of 12 volts. This coaxial DC plug may or may not be included with the LED strip you purchase.

If the plug is not included, then see if you can salvage any old jacks to use. I found an old coaxial jack for  some device that has long since broken and so I cut it, stripped the wires, and connected that to the XT60 plugs commonly used in RC planes. See pictures above to see how I did it.

After prepping the power jack, then find a 12 volt source - either through the wall or through batteries, depending on if you want the project to be portable or not. I used a 12 volt battery pack that was left over from the Solar Plane Project. That had a XT60 plug so I conveniently plugged that into the coaxial jack.

Cutting & Soldering the LED Strip
Cutting the LED strip is easy.
First, measure out how long you want the strip to be and cut it at that length. At 5m, I cut mine to be just under 39 inches each. After cutting the strips, watch this video to learn how to solder the strips to the quick release connectors.

After soldering everything correctly, test the connections one more time and hot glue the soldered area down so it provides insulation and prevents short circuits, etc.

Once this step is complete, you are ready to mount this onto the Rear Foam Boards.

Step 4: PVC Pipe Assembly

The PVC pipe assembly is pretty easy. All you need are 12x .5" thick PVC pipe pieces and 4x 3" 1/2 " PVC pipes. For the connectors, you need 10x 1/2" T Joints and 2x 1/2" elbow joints. 

Assembly is pretty self explanatory. Connect them in this configuration demonstrated by my leet skills.
- = 3 in pipe
_ = 12" pipe horizontal
+ = t joint with 12" pipe sticking out the top
# = Elbow Joint with 12" pipe stick out all sides 

#_+- (x2)   +_+-  (x3)


Step 5: Rear Foam Board

The Rear Foam Boards are attached to the PVC Pipes and contain the LED strip. 

To start off, tear out 5 sheets of aluminium foil around 18" in length. These will be taped/glued onto the board. After taping the foil down, take the paper towel tubes that have been cut down to 1" and hot glue one at each corner of each board. These are spacers. 

Next, take each LED strip (disconnect them), and put them in a U shape on each board. Mark 4 locations on the board that are vital the making the light strip curve and punch little holes (on either side of where the LED strip will be placed) there to zip tie the LEDs onto the board. Make sure the LEDs are facing parallel to the foil. 

After zip tying all the LEDs down the each poster, reconnect all the strips together and enjoy the beauty. 

Next, take the Front Boards and place them over the Rear boards. Figure out where the holes will go that will house the zip ties that will hold the two boards together. I punched three holes. Two Holes on top through the towel tube spacers, and one hole centered on the bottom. 

Now before zip tying the two boards together, mount the rear boards to the PVC pipes. 

After doing so, zip tie the two boards together. Then, light it up and see how it looks! Pictures on the next step. 

Step 6: Final Thoughts

Well, connect everything together and light it up! Does it make your jaws drop? Hopefully it will. 

Now that you're done with the poster, rent it out to people, let other guys ask their girlfriends/friends to's good $ for you. Want to know how I asked? I'll write it out at the very end. 

So now that prom is over, or if you didn't make a prom poster to start off with - you can still change what the poster says/. Since everything was zip tied together, all you have to do is cut off the front posters, make new front posters and have a poster that says something completely different. 

Okay, and this is how I asked: I placed the poster in the back of a dark room. (The door was in the back too). Then in the front of the room, I had the projector with the girl's name on it. Then I set a chair in the middle of the room facing the LED poster and then turned off the lights and the LED board. When I led her into the dark room, naturally, she was focused on looking at her name on the project screen. Then I asked her to sit down on the chair facing the rear of the room, as she did so, slightly confused, because clearly her name with an ellipsis was in the front, and as she spun to sit down, I hit the lights on the remote and out pops the words PROM? 

Now how's that? And again, calling out to all engineers/DIY people of the world, if you're willing to help me sometime in the future with my awesome marriage proposal idea at least 6 years (as of 2014) down the road, let me know. Now...all I have to do is find the right girl. :D 

Special thanks to my awesome friends,Phuong & Claudia and teachers who helped , school administrators for allowing me to use the rooms, and the girl that I asked. The project was completed in three days. Good planning before hand contributed to how the efficiently the project was built. Look at the picture with all the layouts and plans. Those things caused more of a headache than the project itself. 

Improvements for future editions: To make an even more professional looking poster, you could use either wood or metal as replacement for the PVC and have opaque glass in place of the drop cloth. And if you want to go all out and be able to change the words without cutting zip ties, you could create rails on the front poster board which would serve as a frame and slide in which ever letters you want into the slots. 

Thanks for looking at this instructable! Feel free to Favorite, Comment, Follow, and  ormake this project! 

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