Introduction: Light of the Lost Triangles

About: Student of Medicine. Fan of instructables since forever. Im fascinated by lights.

Light of the Lost Triangles is a LED Wall Fixture with 4 different modes. Each successive mode features an increase in LED brightness and an increased rate of colour transition. The light looks great and is great for parties too. The cardboard concept can be modified and can be used at a large scale, for entire walls. I am thinking of doing that, If I do, will make an instructable about it.

You can watch a video of the light here.

Its very easy and fun to make, no expert level electronics knowledge required. Basic soldering skills and patience are required though. So lets get started.

Step 1: Ingredients


  1. Cardboard
  2. Wires
  3. White Glue (German Glue) (Carpenter's Glue)
  4. Colour Changing LED's (Number is Variable)
  5. Sandpaper
  6. Hot Glue Gun.
  7. Hot Glue Sticks
  8. Wires
  9. Diffusing Medium - Glazed Paper or Frosted Glass
  10. Wooden Planks for Frame
  11. Soldering Iron
  12. Paper Cutter
  13. Paper Tape (Insulation
  14. Glazed Paper - Frosted Glass

Step 2: Thinking It Through...

Before starting, you have to decide on some particulars.

  1. Decide on the dimensions of the light you're making. This is dependent on where will you place it and the size of the room. Measure the location with a meter tape and make a mental image of how the light will look hanging there. Measure for a square.
  2. In my case I wanted it to hang on my bedroom wall. I decided on a 6x6 meters.
  3. Now decide on how many triangles your light will have. The triangles will decide how many LEDs are going to end up in the project. Draw a crude model on a piece of cardboard to get your coordinates straightened out. Avoid too large and too small triangles.
  4. I decided on a 6x6 size with 52 Triangles and 52 Colour Changing LED's.
  5. We are going to use a AC Universal Adapter for this. Here is the photo of the one I used. Using this adapter gives 4 different modes to your light with increase voltages.
  6. Get a circuit diagram for the light from this link.

Step 3: Making the Frame:

You have to make a frame to house the light. I wont go in the particulars of how to do it. I chose to go with a wooden frame. Add a hook on the top of the frame to make it easy to hang it later. If you intend to polish the wood or add any refinements, do it now as there wont be a chance later with electronics inside.

The photo shows the completed frame lying on top of my table.

Step 4: Cardboard Fiesta

  1. For making the walls of the triangles and the circuit board I used cardboard. I chose cardboard because its easy to manipulate. You can get cardboard from your local grocery shop.
  2. Take an even piece of cardboard
  3. With a ruler and a marker divide it into equal sized strips. The size of the strips is dependent on your frame.
  4. Make a strip and measure it against the wall of the frame. You want to leave some place below the strip for the circuit board later. The wall of the frame I made was 2.5 inches in width. I made each strip 2.4 inches wide.
  5. Make sure the strips have smooth edges and are of equal size. You can cut one strip and use it as a standard to cut other strips.

Step 5: Triangles Are Cool

  1. Now you have to make triangles. Its good if you already have a layout in mind for the design of the triangles but if you don't you can just go random. I have made a couple of these kind of lights and I just randomly make triangles.
  2. The good thing about triangles is that you dont have to worry about the size of the sides as long its three straight lines meeting each other, its a triangle. You do need to be decided about the number of triangles before hand
  3. Put the frame on a smooth, even surface.
  4. Take strips, make triangles. and use generous amounts of white glue on joints.
  5. Keep count of the triangles as you make them. Its a drag to count them afterwards.
  6. Keep making triangles and apply liberal amounts of glue on
  7. the joints and even on weak surface.
  8. The more glue you apply the more rigidity the triangle frame will acquire.
  9. Once you have made the triangles leave the frame for 12 hours. It take 12 hours for white glue to dry. (12 hours - Drying Time / 2 Days - Curing Time).
  10. After two days the frame will be rigid and snug. You can tell if the frame is dry by the colour of the glue. White glue becomes transparent when dry.

Step 6: ​Making the Circuit Board.

  1. Cut a cardboard square equal to the size of the frame. The cardboard should be able to fit into the frame.
  2. Place the cardboard under the frame. Take a marker and put a mark in the centre of every triangle. This is the place where the led will be. Make the mark thick and distinct.
  3. Take the cardboard square and using a pointy knife or a screw driver poke holes in the cardboard at all the places where the marks are. Make the holes wide and open. Keep in mind that these holes will house the LED's later.
  4. Try not to damage or tear the cardboard as you poke holes in it. Do it slowly and carefully.
  5. Use white glue to coat the surface of the cardboard and leave it to dry. This will give the cardboard much needed rigidity.
  6. I spray painted the circuit board and the triangles at this point. I used silver colour to make it more reflective.

Step 7: LED Diffusion and Osmosis

  1. You have already decided on the number of LEDs. Buy RGB LED's. I bought 55 LED's from my local electronics store. They were 14 cents a piece. The LED's turned out to have 7 colours, which was a pleasant surprise. They are the main expense of this project.
  2. You need to sand LED's to diffuse their light. Sanded/Diffused LEDs are available but they are expensive. Sanding is not easy. It takes a lot of patience and time. Keep a button cell with you to check their diffusion.
  3. This instructable explains the diffusing process quite adequately. Wash your hands after sanding LED's.
  4. Diffusion is specially important if you later intend to use glazed paper as a diffusing medium. It can be discounted if you are going to use frosted glass.

Step 8: Making a PCB.

Although cardboard is easy to manipulate I didnt know that solder doesnt stick well to cardboard. I forgot/got lazy to take photos while making it. Im going to explain it through finished photos.


1. Get a LED Circuit Diagram for your array from this website. You Just have to put in the number of LEDs The source voltage and it will give you a circuit diagram.

1. For 52 LED's the wizard gave me 13 arrays of 4 LED's each.

2. I took a marker and divided the holes I made earlier into a set of 4 each. These are the individual arrays. Number the arrays.

3. Add a marked line that passes through each array - "at least once". Decide that this line is going to be positive or negative.

4. Take another different coloured marker and make another line like that, parallel to the other line, also decide on the polarity of this line. Dont confuse the polarity as it can potentially screw up the project later.

5. Using different colours will help you keep track of positive and negative which is very important.

6. You basically now have a PCB diagram of your light. The holes are where the led is going to be and the lines represent the power source.

Step 9: Making the Circuit.

  1. Take two wires, strip the plastic off of them.
  2. Now lay the wires on the lines you made earlier. I secured them with small gobs of hot glue. Only use hot glue as other adhesives can impair conductivity. Connect the adapter at the start of the wires.
  3. Once the wires are laid down, you should check by lighting up a LED at the end of the wires. If it lights up youre good to go!.
  4. Install LED's array by array. Make sure not to lose the track of the polarities of the wires. Check each array as it completes.
  5. Once its all done use a ton of hot glue to freeze each piece of solder in its place. It will all become very untidy and ugly but it doesn't matter its going to be facing the wall anyway. This is necessary because solder doesn't stick to cardboard well.

Step 10: Diffusing Medium

  1. Tape the circuit board with the back of the fixture. You can also use hot glue to permanently secure it.
  2. Now for a diffusion medium you have to use glazed paper or frosted glass. I used glazing paper in earlier projects because its very easy to manipulate and I didn't have experience working with glass..
  3. Cover the front of your fixture with the paper or use frosted glass. Glass gives more diffusion and a professional look. Glass is heavy though and needs to be secured with silicone.

Step 11: Lighting It Up. Videos.

  1. The Light of the Lost Triangles is ready. Light it up and bask in the glory.
  2. Increasing the voltage from the adapter gives you increased brightness and rate of transition.
  3. I prefer to keep it at 6 volts, the mode 1 in the video, its slow and nice. At the 4th mode (12 volts) it transitions too fast.
  4. I hope you like it and make it. Do tell me if you make it.