PIC16F877A Based Led Matrix Controller

The objective of the project is to control a scrolling LED Matrix Display remotely. This display may be used to display any texts, some special symbols and digits. In addition, some special texts from the Internet (such as news titles) can be displayed on this matrix. The display is appropriate for a signboard in shops or some particular places.

Led Matrix Controller Circuit

There are some common LED Matrix displays in the electronic markets. The resolution of these modules is 8×8 or 5×7 generally, and the outline dimension of them is around 28×28 mm. Moreover, some types of matrices with an existing controller circuit are used for projects commonly. However, my objective was to design and make my own big display because of that the matrices in markets have not enough size. A pattern was designed to align LEDs perfectly as much as possible and all LEDs were soldered each other.

Assembly of LEDs

The distance between each led is 1.25 cm and the total size of the matrix is 10×30 cm. The resolution is 8×24, accordingly, the total LEDs on the display are 192.

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Hardware

The circuit that controls LEDs was designed and simulated on Proteus-ISIS before testing it physically. The main reason for using Proteus is that a circuit based PIC16F877A can be simulated on Proteus.
After simulation of the circuit, a PCB that would control display was designed on ARES.

All parts used on PCB are listed below:

• PIC16F877A
• 20 MHz oscillator
• 2 x 22 pF capacitors
• 25 x 220 Ω resistors
• 1 x 1k Ω resistor
• 1 x 1k Ω resistor
• 1 x Green LED
• 1 x ULN2803
• 3 x 74HC595
• 1 x 100 uF capacitor

Other components and modules used for the project:

• HC-05 Bluetooth Module
• 192 x Red LEDs
• 11.1 V 900 mAh LiPo Battery
• LM2596 Step-Down Module
• 1 x Button
• 1 x Switch

PCB

The final version of PCB is shown figure below.

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Software

User interface for the project was programmed via C# on Visual Studio.

Source code was written on CCS C Compiler.

C Source File

***Also, I am planning to upload a video on YouTube soon.