Today I am going to show how to make 5×7 LED dot matrix board. In this post i will demonstrate to build the board and show you to use it manually. I will post the programming and interfacing with arduino as soon as possible.
Step 1: COMPONENTS NEEDED
These are the components. To build the LED dot matrix board.
°• 35 tested LED ( I used RED colour)
°• PCB board small sized
°• female socket
°• 100 ohm resistors = 5
Total cost = 70.00 INR
°• 6V DC supply
Step 2: LED's & SCHEMATIC's
This is 5mm THD(Throw hole device) LED.The long terminal indicates positive and short terminal indicates negative.
The above shown schematics is circuit for 5x7 LED dot matrix board. while building the circuit neglect the DP LED.
Step 3: Building the Circuit in PCB °•STEP-I
First place all the LED's in the PCB board then bend all the negative terminals horizontally. Then solder all the terminals in row wise, Finally one terminal from each row. So totally 7 negative terminals.
Step 4: STEP-ll
Before making positive connections insulate the negative terminals because it is bare opened. It may lead to short circuit. So I insulated it by paper chart as shown in the picture.Then solder all the positive terminals towards vertically down, After soldering there is one output terminal from each column totally 5 positve terminals.
Step 5: INPUT SOCKETS
Use seperate female sockets 5 pin sockets for positive terminals similarly 7 pin sockets for negative terminals.
Step 6: POWERING
To power the board use 6v DC supply for protection use 100 ohm resistors
Step 7: WORKING
First to activate the single LED in the board give positive input to first pin of the column pin set and negative input to first pin of the row pin set. The first LED starts glow, likewise test all the LED's in the board. Depending upon the character you want in board turn ON the corresponding LED.
Step 8: Scrolling Text
To make scrolling text arduino is used I post the programming and circuit for scrolling texts in the board as soon as possible.