If you are a maker you must like making to stuff. We all do! Isn't it awesome when someone asks you what are you doing and you are like "I am just making cool things with my hands"? When you are going to a contest, school or maker fair (I wish to be there one day) you want to show everyone around that you are a maker. Because of that, I thought that some kind of LED sign would be cool. Maybe I should 3D print one and put some LEDs inside it? No, that's not cool enough. How about a big PCB with a lot of LEDs that are arranged in some text let's say "I MAKE STUFF"? That sounds perfect! So that's why I made it. Maker badge that's how I called it is a very simple project for beginners, so if you want to start with soldering or electronics you can by making this project. There are a lot of things to solder (almost 100 LEDs) but all of the components (except one that is optional) ar THT (through-hole technology) so those are easy to solder. If you want to have a cool LED sign keep reading :)
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Step 1: What We Will Need?
Let's start with parts that we will need to make this project. There is not a lot of different components but there is a lot of LEDs. To save some money on them you should find the cheapest possible, try to find them in China. Parameters of them are 2V and 5 mm color is up to you. If you want you can also buy a complete kit with all the parts, except USB socket or PCB only right here on Tindie:
PCB is a huge part of this project so if you don't have one it may be hard to do it, but you can try to make it on a protoboard. If you want to make PCB on your own you can find all of the files in the next step.
And here is what we will need:
Step 2: Schematic, PCB and Some Math...
This project is quite hard to make on protoboard or breadboard so PCB is the best way. If you want to make PCB on your own you can find all of the files right here. There is also schematic with all of the connections, an I would like to explain some more why everything is connected like this. As you can see on the schematic (take a look at the image above) there are 6 blocks 16 LEDs in each one. In each block, there are 2 LEDs connected in series and then 8 of those connected in parallel. Together that's 16 LEDs and that's one block. You may ask why is this connection so sophisticated. Because of resistors, I wanted to be able to power it with 5V, 2 LEDs connected in series can be powered with 4V (2V each) so we need a resistor that will take 1V. But each LED takes 0.02A of power that's equal to 20mA so if you will multiply 0.02 by 48 (we have 96 LEDs connected in series in pairs and then in parallel, this is why 48) we have 0.96A to know the power consumption we have to multiple voltage by current (P=I*U) P=4.8W and power on the resistor is equal to 0.96W. The most popular resistors can output max 0,25W that's why we cannot simply connect all of the LEDs to one resistor. It is possible to connect 4 resistors in parallel to have 1W of max power but we are very close to it so resistors may overheat a lot or even burn. We don't want that to happen. There is also another problem if one f the resistors will break there will be too much power on rest of them that they will break too and it can even break our LEDs, we don't want to burn 100 LEDs. The best way in my opinion to do it is to divide them into six blocks and connect them as shown on the schematic, that way we have 2 LEDs in series and 8 of that pairs in parallel (together 16 LEDs) so current of this block 0.02*8 = 0.160A and power on the resistor will be around 0.160W, max power of the resistor is 0.250W so it is very safe way to connect it and we used only 6 resistors. That's a lot of numbers, I did my best to explain why I have made it that way, I hope you understand at least something :) I promise there will be no more math, let's start making!
Step 3: Soldering a USB Socket (optional)
This part is optional because it is quite hard to solder this thing especially if you don't have experience. Obviously thanks to this part it is super easy to power this thing, you can just simply use a smartphone charger, but for beginners, it may be confusing. I will talk a little bit more about powering this thing in next steps if know how to solder this socket just do it, if not move on.
Step 4: Soldering Resistors
There are six resistors to solder. My advice is to solder them on the back of the PCB or protoboard so that they are not visible to the user. Put them in place and solder, simple as that :) You can see on the images above how it should look like, there shouldn't be too much solder but the whole hole should be covered with solder.
Step 5: Soldering 100 LEDs
It's time for a fun part :) 100 LEDs, well 96 to be precise. Seems like a lot but soldering is quite pleasant and fun to do. Soldering all LEDs at once is not a good idea, you should solder each letter separately or even just part of the letters. If you just starting with soldering solder one LED at the time, make sure that it adjoins to the board perfectly and that you are satisfied with you solder, then move on to the next LED. It's very important to start slowly and try to improve you soldering on each component. That's why this project is great for beginners - there are a lot of components. Remember about LED polarity shorter leg is negative and longer leg is positive. There is one straight edge on the side of LED make sure that it matches with the straight line on the PCB. Once you soldered some LEDs remember to cut out legs of them, you will have more space and it will be easier to solder next one.
Step 6: Cut Out Legs of LEDs
Once you finished soldering remember to cut out all the legs of LEDs and resistors, we don't want ant shorts here. You can do it with any tool that can cut even scissors will do.
Step 7: Soldering Switch and Breakaway Header
The last two parts that we have to solder are a switch and breakaway header. The switch is there to turn sign on and off, break away header is to power it. Another function of this switch is that it can stand straight thanks to it so you don't need any holder or support. To keep it low profile I used bent breakaway header (I am sure it is not a proper name for that but you know what I mean). Solder both of those components on the back, the same side as resistors.
Step 8: How to Power It?
As I sad in step two the best way to power it is to use a smartphone charger but because it is hard to solder the socket for it I added a breakaway header so that you can power it however you want. You can use anything between 4V and 5V (brightness will be small for lower voltage). Power supply, batteries, solar cell, 1S LI-PO battery even lab bench power supply as I do :)
Step 9: Conclusion
In my opinion, this project turned out amazingly good! I love LEDs and sign made with LEDs is cool, it looks a little bit like a neon sign :) Let me know what you think about this project in the comments and don't forget to follow me on social media: