Using a Dot Matrix LED with an Arduino and Shift Register

The Siemens DLO7135 Dot matrix LED is one amazing piece of optoelectronics. It's billed as a 5x7 Dot Matrix Intelligent Display (r) with Memory/Decoder/Driver. Along with that memory, it's got a 96-character ASCII display set with upper and lower case characters, a built-in character generator and multiplexer, four levels of light intensity, and it all runs on 5V.

That's a lot to live up to, and at $16 a pop, it definitely should. While spending half the day at my favorite local electronics shop I found a bin full of these for $1.50 a piece. I left the store with several.

This instructable will show you how to connect to these dot matrix LED's and display characters using an AVR-based Arduino. If you've read any of my previous guides, you may get the idea that I'm often in favor of the most parsimonious solution, and you wouldn't be wrong, even if I do fall short of the goal from time to time. Therefore, I'll also go another step in this instructable and show you how you can reduce the number of I/O ports needed to drive these big, honkin' dot matrix LED's.

Step 1: Get the Goods...

For this short little project, you will need:

• an AVR-based microcontroller like an Arduino or any of it's ilk. These instructions could probably be adapted to your MCU of choice.
• a DLO7135 dot matrix LED or other in the same family
• an 8-bit shift register like the 74LS164, 74C299, or 74HC594
• a breadboard
• hookup wire, wire cutters, etc.

A soldering iron isn't needed, although I use one later; you can get by without it.

Comments

[jonesjalapat]

can you give some details on how to display letters in led matrix..so that i can write a program .Atleast give some sources from which i can refer.

[nevdull]

I'm not sure I understand. I excerpt parts from my AVR/Arduino code on sending characters directly to the DLO, as well, I include the complete source files on the page for download.

[mr.future11]

nevdull- i want to make the display of my own 8*8 matrix can u help me on dat.

[nevdull]

You can build your own with a charlieplex circuit (do a search on here or google for charlieplex) or, alternatively, you can buy an led matrix that could save you lots of soldering and let you get on to the core of your project. I've found good LED maxtrices on ebay, just do a search for something like "led matrix."

good luck!

[OZeP_99]

can you please give me a family of the DL07135?...tnx^_^

[nevdull]

How about here at avnet.com?

Good luck!

[OZeP_99]

just a follow up question...TOM-1057BH or TOM1057AH...wud that thing can work out replacing DLO7135?...having a prob about the shipment bcoz of time...needed badly asap

[nevdull]

they look similar but i dont know if the TOM* parts are "smart" in that they have a built-in character generator, etc. otherwise, you'll have to manage all the rows and columns and generate characters in your code. check first before you buy those TOM parts; my guess is they're not a direct replacement for the DLO but I don't know. Good luck!

[OZeP_99]

do you have any alternative parts for that LED?...maybe they do(electronic shop here) has an avilable LED like the alternative...thank you so much

[nevdull]

The only parts #'s I know for sure are the Seimens' DLO# numbers, but if you do a search for "dot matrix LED" you will get a good list that you can look through. Just make sure they are "smart," that is, have their own character set, otherwise you'll be stuck doing that on your own. Good luck!

[jeff-o]

Wow, I've got to get myself some of those displays! Thanks for the instructable on how to drive them. :)

[nevdull]

They are really neat displays. If you ever run across any in a local shop priced cheaply, they are worth picking up if just for their versatility and ease of use. Thanks for stopping by!

[jeff-o]

I'll keep my eyes peeled - they're hard to tell apart from regular dot matrix displays, though...

[nevdull]

Yeah, I stumbled on mine by total accident...serendipity in motion. They're available online from the major distributors, but they're pretty spendy...

[jeff-o]

I know, I checked. ;) I've got a project I'm working on that could have used one, though the display itself is too small. I need a taller display - do those exist?

[nevdull]

This DLO series is only 5x7 although they make a taller one, the DLO4135/4137. But only the package is taller. The display is still 5x7. I attached the datasheet to this page if you want to get an idea of how the taller one looks, but I'm not sure that's what you're looking for.

[jeff-o]

Yeah, by taller I meant bigger in general - 2" high is what I'm after...

[nevdull]

Maybe something like this could work? They're 2.3" . I have no experience with it though. Just ran across it.

[richms]

Matrixed displays need to be refreshed, and when I last looked at it, setting up a timer in arduino was hard and made other things break which is why they didnt support doing it. I did get it working with normal AVR code, driving some shift registers to make 3 row 14 column LED clock that was a rip off of the aluminum cased one you see from think geek all over the place. As I have no proper time source and the AVR and ardiuno is hopeless at keeping time I have not taken it to completion, but it is displaying random blinking patterns which lets face it is all that is needed. I might get it close enough to complete to write something up before the weekend.

[nevdull]

I'm not familiar with the Arduino way of doing timers, per se, but straight C/C++ or assembler with timers is pretty straight forward. There is an excellent tutorial over at avrfreaks.net if you search for a timer tutorial. Also, you only need to refresh at 30kHz or a little more to remove flicker. good luck!

[jeff-o]

Those are the right size (and pretty common) though they aren't intelligent like the module you have. Bah, maybe I'm just being lazy! I'm sure there's a nice library out there that makes it easy to interface a 5x7 module to an AVR with a minimum of fuss.