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LED Display?

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Hi there,


I'm new to electronics as well as micro controllers, so please be gentle :)


I really want to create a net of LEDs to hang on my window during Christmas, and use the LaunchPad to control it (I'll be writing the code in Energia). The problem is, I don't know how to start.


Could someone please clarify what steps need to be taken to create such a project? I'd like a net of leds, say ~30x30 or so, maybe bigger so I could write text on it, or smaller, simply to share the Christmas spirit :)


After viewing some tutorials on wiring LEDs and controlling it with the LaunchPad - seems easy. But how do I wire up and control 100 or 500 or 1000 LEDs individually?

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this one might be interesting for you, and you should be able to reproduce something similar on a smaller scale for your window.

benefits of this solution are: Full RGB color, each light individual addressable, not that much electronics involved, probably only a launchpad, one or more of those LED strips and maybe a few passive components.

Downsides are that you don't learn that much about electronics and LED driving methods like multiplexing ore charlieplexing, and the relatively high cost (http://www.amazon.com/Good-Tidings-7200 ... 0045PTKNE/)


Just a suggestion, anyway ;)

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Thanks for your response :)


I want to keep it DIY, I'm not interested in buying a final product :) What I do want fo find out is how to control a large number of devices, in this case multiple LEDs individualy with one main device (LaunchPad). Later on I'd like to create a 3D LED cube, but getting a 2D display is a start :)

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My goal is to create something like this:



Only without having such an input :) I'd do the actual reading of required text/animations from my PC via serial, or hard coded into the MSP430, but I believe there isn't enough RAM to handle that, so I guess serial communication is the best option. It's just that I want to figure out how to wire up and control those LEDs individually with the MSP430.

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then this one might be interesting for you: http://www.evilmadscientist.com/2009/peggy-2le/

not the kit or the board itself, but the open source code and build details for it: http://wiki.evilmadscience.com/Peggy_2

It is based on an Atmega with an Arduino bootloader, so the chances of porting some if not all of the code to energia are quite good ;)

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Driving a large number of LEDs with a small number of pins is a very common challenge with microcontrollers. Many different ways exist to do this so choosing which one you want to use is dependent on many different factors. Because of this I will link you to some very detailed discussions that will allow you to choose which avenue you would like to pursue.


A great MAKE Magizine forum posting on the subject

http://forums.makezine.com/comments.php ... ionID=5356


The stackoverflow of electronics has some really good input as well

http://electronics.stackexchange.com/qu ... n-my-micro


EDIT After posting I remembered an awesome RGB LED table project that uses a launchpad and an array of LED drivers.

http://e2e.ti.com/group/microcontroller ... 47779.aspx


And their code is here



This should give you a solid start.


So find a method you like and start implementing it. Ask questions along the way and we can help you get started in no time.

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Thanks for the links.


So as I understand, my best option would be to use shift registers. Of course I have more questions about them, I hope someone here is patient enough to guide me through this :)


I found a video showing that it is possible to successfully control a large-ish number of LEDs with the MSP430



My question is.. or are


a) Am I limited to a set number of shift registers in terms of connecting them, or is it limited to the processing power the MSP430 can handle? Or both?

B) Controlling. As I understand, I could connect the shift registers (don't get it if directly to the MSP430 or via another control interface). How would I be able to interface with specific shift registers, to power on/off the required LED(s)?

c) Wiring. Kinda combines both questions. Is it possible to connect one shifter and then forward information to the next with on of the pins, or .. Just .. How to wire everything up?

d) Does Energia support interfacing with registers? And is it "plug&play"?

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Look at this example, there are 4 shift registers which can be used to drive 8x24=192 LEDs.

Here's the same board driving 128 LEDs (16 segments x 4 digits x 2 colors.)

If you want to experiment with shift registers, here's something for you. One board will let you drive 4x4 LED array (don't solder LEDs and use 74HC595, 4 outs to drive cols and 4 to drive rows.) Two boards will let you drive 64 LEDS, one board with TPIC6C595 for cols and one with 74HC595 for rows.

I am also working on a HT1632 board which will allow you to drive 256 LEDs (with 2 HT1632 boards, you can build 8 x 8 x 8 cube and you don't have to multiplex!)

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