Scrolling Led Display Project

Hello,

I've suddenly found myself in a little bit of a situation, months after submitting an art proposal I have now got the go ahead... problem is I thought I would have many months to get involved and learn how to do this myself, but time is short and I need to get hacking.

Anyway I need to build a scrolling Led display of 32*8 which is interfaced to a pc able to receive a text data output most likely from a flash app.

From what I have seen so far my current thinking is I will get the 4 panel kit from modern devices since it appears to be able to provide enough current for super bright Leds, and will also be easy to solder connectors onto the panels (as the leds will be separate from the panels). Only down side to this is it will require meters of cabling but for the ease of a designed pcb etc it could be ok... or are there any other suitable alternatives using Led addressing?

My biggest challenge however is the software to control the display. Can anybody provide links to code that can do this?

Many Thanks

Just a quick question...

With having 4 boards like that will you have enough pins on the arduino... They seem to have 9 pins each... Or are you going to use the arduino mega?

Also with having 4 boards like that, there won't be any standard coding for it, you are going to have to write your own. It also depends on what you want to show on the board. Is this for a one off message or will you want to be able to change what it says more easily?

Mowcius

At the moment I haven't decided on which arduino to use, am open to any suggestions.

What resolution Led boards would there be standard coding for? This board will be showing a continuous stream of text messages (around 20-150 characters) , the data would come from a text file or rss feed that continually gets updated with a new message.

Basically I am looking for the LED circuit able to drive bright leds (preferably kit form), and the software to control it as I'm sure others must have done similar projects.

thanks.

Well, I can tell you that the Mega is way cool and should have plenty of pins to drive 4 of the Modern Device boards, but you can certainly email Paul Badger at Modern Device to confirm. He's a great guy... hey, he even sells a 4 panel kit.. so... should be good to go.

Unless you are going to be confined for space, I would recommend the arduino mega because it would allow you to do simpler coding for the project and it gives you more pins to play with should you want them in the future...

The standard Arduino is perfectly suited to this job. All you need to do is use a set of shift registers or an LED Driver IC and then only about 3 pins would be needed from your Arduino.

Shift Registers like the 74HC595 multiplexed will provide more than enough power for yoru set-up and are very easy to code for.

I would agree with 'Mike Mc' about a standard arduino:

The standard Arduino is perfectly suited to this job. All you need to do is use a set of shift registers or an LED Driver IC and then only about 3 pins would be needed from your Arduino.

Shift Registers like the 74HC595 multiplexed will provide more than enough power for yoru set-up and are very easy to code for.

It depends on how you want to do it... This makes it 'simpler' but you have to source another board...

or buy the IC and make your own... :smiley:

I found this project (although not arduino) that seems to do exactly what I need, including the software to display live data.

http://koti.mbnet.fi/zyc/LedDisp/

Does anybody know what current would be available to the LED's? would I be able to use superbrights?

As a general rule, superbrights consume more money, not more current ;D

And sometimes more voltage: it's not uncommon for them to need, say, 3.2-3-8V, rather than the 1.8-2.2V that's typical of standard-brightness LEDs. Which would mean you'd need to change the value of the current-limiting resistors.

Be sure you check the voltage requirement when shopping for LEDs. And go for lower voltage ones if you can: transistors aren't perfect switches, and there's going to be some voltage drop across the outputs of the 74HC595s and the row-driving transistors.

Ran

It depends on how you want to do it... This makes it 'simpler' but you have to source another board...

or buy the IC and make your own...

No you don't. You just need 3 pins from the Arduino, no more, and daisy chain the shift registers. Use one for yoru common anode/cathode all wired together (perhaps with transistors if not enough current) and the rest to control the columns.