Want to use LED Dot Matrix Board

[masterleous]

Hi all,

I want to use LED DOT MATRIX Board, I bought a newone having 8*8 LEDs, means This have 8 Columns and 8 rows, and their are only 16 pins........... ???

I am unable to use it, can anyone help me to understand how we can make letter on it. or how we can make any thing with it.......... :'(

Thanks in advance  8)

 

[audioguru2]

Instead of having a separate wire for each LED which would require 65 pins and 64 transistors to drive the LEDs, they are connected in common so that they can be multiplexed.
Search Google for one of many LED Oscilloscope circuits.

 

[MP1]

Masterleous,
A Matrix works on a X-Y table. For example, if you call the horizontal rows X (x1, x2, x3, etc.) and the vertical rows Y (y1, y2, y3, etc.), then you can control each LED by making sure that a specific X row has voltage and a specific Y row has a ground. Since the LED needs both of these parameters to light, you have complete control over each of the 64 LEDs by determining which of the 8X's get voltage and which of the Y's get a ground. To go further, if you connect volts to X1 and connect ground to Y1, the first LED in the matrix is lit. If you connect volts to X1 and ground to Y2, the second LED in the that same row is lit, etc. with this method, you have individual control of each by using a combination of X and Y.

Hope it is a helpful explanation.

MP

 

[masterleous]

Thanks audioguru & MP,
I tried this method on it, and it was working.............but the problem is that i want know the exact order......mena s just like a 7 segment which has pins like a b c d e f g h..............i want to know the exact pin location of this 8*8 matrix led........i tried to search it on google but i found a 5*7 matrix led instead of 8*8...........
can anyone send me a link or any helpfull material about 8*8 sequance........and how i can show a Letter on it..........i get the pins connection for 8*8 by head and trial method..........but unable to display a character.........
Thanks

 

[nanakis1]

There is an interesting site, that is also mentioned in electronics-lab site, www.datasheetarchive.com . There you can type in search box whatever you want, for e.g. led dot matrix, and check the decription search botton to find your request.

 

[audioguru2]

Hi Nan,
If you can't find the datasheet for your LED matrix board, it would take you only a few minutes to make your own chart of its polarity and  how its pins connect to its rows and columns. Simply use a 4.5V battery (to avoid the 5V max reverse voltage rating of LEDs) in series with a 470 ohm resistor (to limit current through each 2V LED to about 5mA).  ;D

 

[masterleous]

Hi audioguru n MP,

I try to locate the pin no.s of 8*8 LED Dot Matrix Board n got success.

There are total 16 pins. 8 pins for 8 column and 8 for 8 rows.

The 8*8 LED Dot Matrix is look like as below......

  - - - - - - - -
  - - - - - - - -
  - - - - - - - -
  - - - - - - - -
  - - - - - - - -
  - - - - - - - -
  - - - - - - - -
  - - - - - - - -

Let us assume that '-' is a LED, Let for Example i want to display Capital Letter 'N' than it will just look like

  * - - - - - - *
  * * - - - - - *
  * - * - - - - *
  * - - * - - - *
  * - - - * - - *
  * - - - - * - *
  * - - - - - * *
  * - - - - - - *

For this purpose i have to make LOGIC HIGH for Entire Column 1 & 8. And Other Single Line which is a DIAGONAL..... 6 separate Column and their respective rows will be LOGIC HIGH.

But the problem i am facing in doing this all Column and ROWS will be LOGIC High and golw all LED (8*8) instead of Letter 'N'.

My question is that could we required any Latching Circitry for this or any Special Driver IC, than plz give the full detail.......

Thanks,
masterleous 

 

[audioguru2]

Hi Masterlieous,
You must multiplex the display by lighting each column one-at-a-time, one after the other at a high frequency so that your vision is fooled. It is fairly complicated so I'll let someone else tell you how they already did it.  ;D

 

[masterleous]

Hi Masterlieous,
You must multiplex the display by lighting each column one-at-a-time, one after the other at a high frequency so that your vision is fooled. It is fairly complicated so I'll let someone else tell you how they already did it.

 

[trigger]

Like audioguru said, only one column will be considered at a time.
At the same time, you can determine which LED in a row will lite.
Each column will state on a very short period of time and loop.

I think it is no more method to make the LED matrix lites as you decided.

 

[masterleous]

Like audioguru said, only one column will be considered at a time.
At the same time, you can determine which LED in a row will lite.
Each column will state on a very short period of time and loop.

I think it is no more method to make the LED matrix lites as you decided.

Hi,
Yes u are right........
I want some help to drive LEDs.............can anyone have any idea........
I think the minimum frequency for driving it should be greater than 5-10 K Hz...........am i Right?

 

[Shahriar]

Hi everyone

I know how to use matrix displays an how to multiplex them but I have seen some of these boards in streets in very big sizes.
the display animatimations. for example the word "NEC" will move in many directions with too many effects. how do they write the programs. Is there a Simulator for these Boards? What EEPROMS theu use for their  Microcontrollers to store such Big size programs.

ThanX - Shahriar

 

[bj_edison]

I wanna know more abt this too, pls kindly help

 

[EdwardM]

Hi

one of the ways of driving a LED matrix is to use dedicated IC's from various manufacturers, for example:

http://www.maxim-ic.com/appnotes.cfm/appnote_number/1033
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/1339
and this one
http://noisybox.net/electronics/LED_sign/

Best of Luck

Ed