I had dozens of led lying around and didn’t know what to do with them, so I decided to build a Led matrix that can display anything you can think of,
So let's get started!
Step 1: Watch the Video !
If you don't want to read all the stuff you can watch my video.
Step 2: Everything We Need
3) Arduino Uno
6) Transistor- 2N3904 or equivalent
Step 3: Matrix Theory !
If you don’t know what a LED matrix is here is a very simple explanation for it,
If we connect the cathode of a LED to –ve of supply and anode to +ve of supply this will be a 1X1 matrix. Which consist of 1 Row and 1 Column.
Similarly now if I take 2 LEDs and short their cathodes this will make 1X2 Matrix and If I add another row to it it will make 2X2 matrix but this time we will short all the cathodes of the LED row-wise and anode column-wise.
Using the same concept we are going to make a matrix which consist of 6 rows and 24 columns
Step 4: Schematic and Gerber Files
If you want to edit my pcb you can do it here
Step 5: Soldering the Matrix !
Place 24 LEDs in a row with Anode on the top side and then flip it and solder anode and cathodes to the points then trim all leads,now short all cathodes of LEDs you can also make a track but I prefer using silver copper wire. Now repeat this process for next 5 rows
Now its time to short all the anodes column-wise. If you don’t have a silver copper wire you can bend the legs of LEDs and solder them
Step 6: Soldering PCB !
Already looking at the complexity of this project which includes 3 shift registers,a 4017 counter, 6 transistors, an Arduino Uno and dozens of resistor I decided to make a PCB which I designed in EasyEDA and Ordered through JLCPCB.
Once PCB arrived first I did some continuity test to make sure everything is proper and according to the circuit and then finished the soldering process.
Step 7: Connections and Programming
In the end, I used male-female headers for the connections and connected everything using wires.
Program for the matrix was originally made by Instructable user Syst3mx,
Update 06/12/18: I have made the modification to make it work for 24 Characters
And it is very simple just use excel file and make all the words or numbers you want, copy it to the code in #define line and edit a line below and you are done!
Step 8: Thank You
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$2 PCB Prototype (10pcs,10*10cm): https://jlcpcb.com