LED Signboard

cbkulatunge · Joined: 22 Oct 2009 Posts: 12

can anyone help me to design a LED sign board?

ezflyr · Joined: 25 Oct 2010 Posts: 1019 Location: Tewksbury, MA

Hi,

I might be interested. Did you have a target pay scale in mind for the project Laughing

?

John

temtronic · Posted: Fri Mar 11, 2011 1:58 pm

Would need to know
1) size of sign
2) pixel count ( x vs. y)
3) display data a) characters ( a-z, #s,etc)
or b) graphics
4) dynamic or static , update rate, refresh ,etc.
5) colour of LEDs, mono,RGB, ?
6) power per LED , pixel?
7) indoor, ourdoor ?
8) data entry interface, PC link,keypad,usb flashdrive,wifi ?
9) message length,# of messages,
10) do you want schematics,code,Proof of Concept prototype,Alpha module ?
11) portable or fixed, available power( 120,240,1ph,3ph,battery )?

cbkulatunge · Joined: 22 Oct 2009 Posts: 12

first i would like try small indoor one like 8x64.

bkamen · Posted: Sat Mar 12, 2011 11:35 am

temtronic · Posted: Sat Mar 12, 2011 12:09 pm

that's cheating !!!

You're supposed to spend hundreds of dollars on parts, and a thousand man hours cutting code and burning fingers THEN go buy one off the shelf !!

bkamen · Posted: Sat Mar 12, 2011 12:38 pm

cbkulatunge · Joined: 22 Oct 2009 Posts: 12

Thanx for reply guys,
I really want to design it my self. First give me some theory of operation.

temtronic · Posted: Sun Mar 13, 2011 7:13 am

theory is simple,
You want to turn on and off a matrix of LEDs based on some 'data'.
Step one is to program a PIC with 8 LEDs(and current limiting resistors) connected to one port. Cut code to turn on 1 LED,then expand your code for more LEDS and patterns.

Step two would be to cut additional code to allow the 'pattern' to be sent from say a PC and then displayed on the 8 LEDs.

For you 8 by 64 display of LEDs, I'd probably use 4 pcs of MC14514, 4 to 16 decoder chips.This would only require 1 port(8 bits) for the data(row of LEDs, on or off) and 1 port(8 bits) to control which of the 64 columns the data is to be displayed.Each column will need a transistor driver and current limiting resistor.

Since this is a matix display, a refresh rate will have to be determined, usually less than 100 Hz,

Step 3, wire up just 1 of the decoders and get it all to work. Once you're happy with the 8 by 16 display, just add 3 more decoder circuits and cut more code...

There are other chips than the one I suggested to build the circuit, but it's tried and true and easy to figure out.I've used it for 3 decades.You can even get single 40 pin PIC to do the whole project,depending on your skill level.