8x8 led matrix Display

Hi to all
I want to make a LED MATRIX PROJECT USING 8X8 LED MATRIX(2 feet long)

I want the message display to be of different patterns....Means scrolling from all sides, fade in fade out,etc.

So,i am using 8051 controller.........please some body help me ....

which Ic's I use or led drivers.

thanks in advance

if any body worked on this project ....please give me guide line.

Hi,

Well I don't know much about the led matrix display. But I think you will need to have ULN 2003 or similar ic for the hardware development. Check out its datasheet.


NIKS

Your question is a bit like "which screws do I need to build an aeroplane?"

Before deciding on a parts list, you need to decide on the method of displaying you want to use. For example, are you using static drive or multiplexing, if multiplexing, what scan rate do you propose and how bright does it have to be?

Is your 8x8 matrix a single character and if so why should it be 2 feet long? If it is multiple 8x8 characters, how many are there?

You need to make fundamental design decisions before putting a shopping list together.

Brian.

Dear betwixt

Thanks for your suggestion

I am using 8x8 led matrix (10)

i want to make a multi scan led display .......means not only scrolling

It can display the characters fade in fade out, scroll from all sides.
Or i want to do every type of scan which is possible with led matrix display

i had made a scrolling message using 8051 and 74hc595 shift register.

now i want some different styles......
Ok tell me can i use latches for scaning the matrix..

please help me

Thank you for the explanation, it makes more sense now.

Firstly, most of the designs I've seen using 74HC595 are not reliable as they use the ICs limited drive capability to stop the LEDs being damaged. This is not a reliable solution and the brightness of the LEDs will not be consistent. If that's the way you are doing it, I suggest using driver transistors between the '595 and the LEDs and using series resistors to control the current.

The way to control the current to fade the brightness is to change the duty cycle of the drive current. It would be quite difficult to control the current using an analog circuit but by making the period each LED is on for will give the appearance of brightness change as long as you do it fast enough that it doesn't appear to flicker.

If you want to have total control over each individual LED things get much more complicated and you have to abandon the normal row and column multiplexing and look at individual LED addressing. You might be able to do it with switched PWM drive to the rows and addressed columns using a shift register but the switching speed might be a problem. You would have to adjust the PWM ratio on each row output in sequence with each column change.

Brian.

Sir thanks for your reply......

Can you please tell me how to make the c code for it ...

or if you have any sample code for 8x8 led matrix display.

led matrix Display sign board

Is here no one who can help me in my project.
Because i have to submit this project in college by next week as final year project.

Please somebody help me.

It's your project, not ours !

You haven't given us a schematic so I'm going to make a guess that your design uses a chain of shift registers. You should have 8 shift registers per digit, one for each row of LEDs in each LED module. The serial out from the first shift register should go to the shift input on the second and so on.

Now all your software has to do is output 80 bits on each pin of an 8-bit port, one pin per line of shift registers. When all 80 bits have been sent, shift the 80 bit pattern into the parallel output latch of the '595 so that row of leds is powered by the binary pattern. At the same time, you need to send a PWM signal to the output enable on the 595, or to the led driver circuit to set the brightness level. You control the brightness by varying the ratio of on/off time of the LED current, doing it very quickly will avoid flicker.

There are better ways of doing this but I have to assume you already have hardware built and are using the devices you specified.

Brian.

led matrix Display sign board

I am using 8051(P89V51RD2) controller .
and i want to display the characters in any pattern.

And thanks very much for the reply

Re: led matrix Display sign board

hello friends
i dont know about decription of8*8 led
plz help me

It's simply an array of 64 LEDs arranged as 8 rows of 8 LEDs to make a rectangle. With it you can light different combinations of LEDs to make the shapes of letters, numbers or symbols.

In the original post, several of these were placed side by side with the text 'sliding' across them. It requires that the contents of each column is moved to the one next to it and a new column is generated at the starting end so the pattern appears to shift to the side. It can be done using shift registers or multiplexing.

Brian.