Custom LED Sign




Ever wanted to make an led sign for one of your projects? Now you can! In this instructable I will show you how to make your very own led sign. I will cover everything from designing your sign on a computer to calculating led values.This was my first soldering project and it turned out great! Make sure to read this whole instructable before you start.

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Step 1: Materials

What you will need:
perf board without pads
soldering iron
windows excel
2 colors of sharpie
DC power supply

dremel or saw

*I recomend you buy diffuzed leds and not high brightness leds. I bought high brightness leds and you are blinded by this sign. When almost 100 leds are shining directly in your face it is like looking into the sun.

Step 2: Design Your Sign

Now that you have everything you need you can start designing your sign! You will be using excel to design your sign. You fill a cell where an led will be placed. To begin, open excel and make the all the cells squares. Then click on a cell and, using the fill tool, fill the cells to make letters. This may take a few trys to get good looking letters. Remember, this is just a rough draft, you can make it look better when you place the led on the clad board.

Step 3: Calculations for the LEDs

To begin your calculations, you need to know the voltage and amperage of your power supply. I didn't trust the power rating of my 12 volt DC power supply, so I tested it with my multimeter. Good thing I did, it was cranking out 21.5 volts. Nearly twice as much as it was rated for! The sad fact is most power supplys put out more voltage than they say. I reccomend you test your power supply so you know its exact voltage. The amperage of your power supply does not matter as long as it is above the amperage your leds are using. Now you need to know the voltage and amperage of of your leds. My leds had a running voltage 3.0-3.5 volts and an amperage of 20 mA or .02 amps. To start, we need to figure out how many leds will be in series. To do that, divide your power supply voltage by your leds maximum and minimum voltage. In my case, it was 21.5 / 3 = 7.16 and 21.5 / 3.5 = 6.14. You need to pick a value between these numbers or lower. I picked 7 so 7 leds will be soldered in series. Next we need to calculate the maximum amount of leds you can have running on your power supply. My power suppy puts out 2.5 amps max. So all you do is divide the max amps of you power supply by the amperage of your leds. The amperage of your leds needs to be in amps not milliamps. Remember there is 1000 milliamps in 1 amp. I my case it was 2.5 / .02 = 125. This means I can have 125 rows of 7 leds in series. That makes a grand total of 875 leds. You can use less than your maximum amount of leds as long as the number of leds in seris is the same. If you need help with your calculations, leave a comment and I will help you.

Step 4: Making It Real

Now we can begin placing the leds on the perf board. Using your excel drawing as a guide, put the leds legs through the holes in the perf board. The polarity doesn't matter because we will be removing the leds and marking their positions. It will thake some repositioning to get the leds to look good. When you are satisfied with the shape of you letters, begin removing the leds and marking where their legs were with a sharpie(pic 2 & 3). When you finish, transfer the design to the back by marking the other side of the hole. When you're done, it will be a mirror image of the design(pic 4).

Step 5: Cutting the Perf Board

This step is optional. You will be cutting and coloring the perf board. To cut the perf board, I used a dremel with a cut off wheel, but you can use a small toothed saw. I colored mine with a large permanent marker, which I do not recomend because It was very streaky. I suggest painting with spray paint.

Step 6: Soldering the LEDs

To begin, mark the polarity of the marked holes with a sharpie. I just put a red dot next to the positive hole. When marking the polarity, remember that the leds will be connected positive to negitive and will be the number of leds we calculated for series earlier. Next, put the legs of the leds through the proper holes. Hold the led tightly and bend the leads over so the led is securely held in place. Repeat the process with another led and snip the leds so they overlap slightly. Solder the spot where the leds overlap and repeat the process with all the leds in that row of series.

Step 7: Making "Resistors"

You will probably have some letters where the number of leds in series is greater than the number of holes for leds left for leds. When this happens you need a resistor. I didn't have a resistor so I made a "resistor". The "resistor" is a led or leds soldered the back and and wraped in tape so it emmits no light. You still need to have the same number of leds in the series and the "resistor" leds count as leds toward your led total. (example: You need 7 leds in series. You have 3 on the front so you need 4 leds as a "resistor" on the back. 3 + 4 = 7) All you need to do now is connect the sign to your power supply and you're done!

Step 8: Your Sign Is Done!

Connect to your power supply and let those leds shine. I hope you enjoyed my instructable!

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    15 Discussions


    4 years ago on Introduction

    I want to connect 60 LED to make a pattern,that runs on can i connect them?? what value of resistors should i use and how??

    1 reply
    Jacks how2sSamannoyG

    Reply 2 years ago

    you should use a 12volt 2 amp transformer and 10k resistors


    4 years ago

    How did you connect to your power supply?


    5 years ago on Introduction

    Can't i connect the positives of all led's together and all negatives together and then connect to the +ve and -ve end of the supply?


    6 years ago on Step 8

    i need to know to 100 leds to connect the world "DIGITALK" how many power supply should i give

    Thanks for the tip, I have never used perfboard. My experience with soldering and electronics amounts to 2 altoids flashlights and a star constellation, a beginner for sure. I am planning on making signs for my nieces and nephews. Do you have a good resource for low cost perfobard, online I suppose? I looked for some at Frys but they were quite expensive, since I am making 4 of these I'm trying to keep the cost down.

    Also, did you use 3mm or 5mm LEDs? You said you recommend diffused LEDs, would you say the same if you were to change the color of the sign to say, green or blue? I appreciate the reply!

    3 replies

    I am not sure where to get perfboard for cheap. I bought mine at radioshack. I used 5mm leds I got on ebay for very cheap(~$6 for 1000). I would still recommend diffuzed leds because when you at the sign straight on it is blinding and when you look at it from angle you can barely tell that it is on.

    Thanks a lot for you help on this, one last question. I have been trolling ebay and trying to find perfboard similar to yours which I have found. What I have not been able to find is the metal that goes over the perfboard. How did you make the nice cover for it? Also how did you mount the sign? I was thinking of using a project box but I don't know how I could get a cover with predrilled holes such as yours. I ordered my LEDs, mostly diffused but I couldn't find blue/purple in diffused so I settled for low mcd. Would you be able to advise me on the wiring?
    My first sign will have these types of LEDs: Size: 5 mm Lens Color: Water clear Emitted Color: Ultra Violet Viewing Angle : Approximately 25 degree Forward Voltage: 3.0 V- 3.2 V Forward Current: 20mA Wave Length (WL):395-400NM Luminous Intensity: 300 mcd-500 mcd Lead Soldering Temperature : 260°C (<5Sec)

    the second:$T2eC16VHJF0E9nmFRpOQBQge!bL3B!~~60_12.JPG

    I bought a number of resistors as well. 

    I didn't make a cover for it, I just colored the perfboard with a big marker. I'd recommend spray painting it instead because the marker looked streaky. I mounted the sign by hot glueing it to knex pieces. I was going to mount it on one of my knex models but sadly I had to take it down before I had a chance to mount it and film the result.

    This is great! I have a question though, I'm new to the DIY electronics world and I was wondering why you wouldn't want to have perfboard with out the copper pads? It just seems like it would be harder without, and harder to find the perfboards. Just wanted to get a reference, for when to (or not to) use the pads. As well as a good place to buy perfboards (on the cheap...) Thanks!

    2 replies

    The main reason I didn't use perfboard with the pads is because it is not needed. The leds have lond enough leads that I can simplely bend them over. This saves solder not having to connect all the pads and makes coloring the other side easy (Black Sharpie looks dull on the board and shiny on the pads). Perfboards with the pads are mainly designed for IC's and more advanced circuits. This project is simply lots of leds soldered is series. There is a big differance in price too. It costed me about $2 for the perfboard in this project, and I have some left over. The perfboard with pads costs $4+ for an amount that I used in this project. I hope this helps and feel free to ask any other questions you have.


    7 years ago on Introduction

    I really like the excel idea for mapping the layout. I did something similar to this for my college graduation cap. I used plastic compatible spray paint to paint the board black and used clear LEDs (12,000 millicandellas). Instead of excel I used adobe illustrator and just made 5mm circles to copy and paste throughout my design. Soldering was time consuming but wire wrapping is a great alternative.

    Dremel is the greatest tool invented since duct-tape.


    7 years ago on Introduction

    This is a well written instructable with great pictures. I have wanted to make led tail-lights for my aging pickup. Older bulb style tail lights are not as bright as the newer models with led tail lights. I am thinking about safety. Your article is so well written that determining the voltage and amperage is no longer a mystery.
    I think it will be possible to get the 12 volts at the tail light connection, leaving the bulb intact and operational. Since the leds will be a lot brighter, they will outshine the original bulb and be more visible.
    Care to write an instructable about upgrading tail lights?? It will be greatly appreciated.
    I will vote for you!!

    1 reply

    Reply 7 years ago on Introduction

    It should be the same process. Just make a sign in the shape of your tail light. I would remove the original bulb, though. The enemy of LEDs is heat, and the original incadecant produces alot.