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deorg
Jun 24, 2009, 10:45 AM
Two questions...
First..
I want to make a wall of 50 Leds lamps, and conected to a kinda like audrino board ( i know It wont support 50 lamps) and ofcourse upload sequences to display that I allready have programed...

anybody know any board kinda a like audrino that are for more led lamps...

secondly anybody know how could I change the secuence through the ipod via wifi...

thanks



LtRammstein
Jun 24, 2009, 10:50 AM
Wow... Huge hobbyist stuff here!

First off, if you have never programmed for a microcontroller before, stay with the Arduino. Sadly, you will need a lot of circuitry from the Arduino to the LED lamps. This is because the Arduino cannot provide the current or voltage to all the LEDs.

To control it via WiFi from your iPod Touch... There's many approaches.

I personally would keep the Arduino attached to the Mac and send commands that way. Attaching a wireless card to the Arduino is very difficult to program with and it just exponentially increases the difficulty of the project.

deorg
Jun 24, 2009, 11:16 PM
Wow... Huge hobbyist stuff here!

First off, if you have never programmed for a microcontroller before, stay with the Arduino. Sadly, you will need a lot of circuitry from the Arduino to the LED lamps. This is because the Arduino cannot provide the current or voltage to all the LEDs.

To control it via WiFi from your iPod Touch... There's many approaches.

I personally would keep the Arduino attached to the Mac and send commands that way. Attaching a wireless card to the Arduino is very difficult to program with and it just exponentially increases the difficulty of the project.


Ive used just the arduino... but, wich one would I need to provide enoght Voltage to all 50 led lamps, and control each lamp like the peggy
http://www.evilmadscientist.com/article.php/ardlibarchive
My team has experience on electronics...

cruzrojas
Jun 25, 2009, 05:03 PM
I would recommend sticking with the arduino, it would be hard to find a micro-controller with 50 digital pins if you are planning to connect one IO per LED. A first straightforward approximation I can think of would be:

1) power the LEDs thru an external power supply, and make sure the power supply can lit all of them at once.

2) use an op-am with feedback to set the state to low or high (on/off) for a single LED. Notice you need a persistent state such that if you were to disconnect the arduino from the rest of the circuit nothing would change.

3) assign an address to each LED and use the arduino to access each LED and turn it on and off. (notice you will need one op-am per LED).

4) finally look into how to access the arduino wirelessly, there are modules for wi-fi and bluetooth available for the arduino. you can use the more convenient for you.

Good luck with such an entertaining project and I would like to know how your project evolves.

Best Regards
Jesus Cruz

Muncher
Jun 25, 2009, 09:07 PM
I would recommend sticking with the arduino, it would be hard to find a micro-controller with 50 digital pins if you are planning to connect one IO per LED. A first straightforward approximation I can think of would be...

2) use an op-am with feedback to set the state to low or high (on/off) for a single LED. Notice you need a persistent state such that if you were to disconnect the arduino from the rest of the circuit nothing would change.

That seems like a lot; you'd need 50 op amps, which (if you used LM324s) would mean 13 chips :eek:. Personally, I'd go with an array of 5x10 LEDs, and use 15 buffered output lines. Then you can wire them up so that the five lines connect to 10 LED anodes, and the other 10 lines each to 5 LED cathodes (or vice-versa). Then, trigger one LED at a time. As long as your circuit is fast enough updating, that would really cut down on the IO lines you need to use (and parts too!). Anyway you cut it, you're going to need at the least: 50 resistors for each LED and a transistor buffer for each IO line.

Obviously, the way I presented is easiest if the LEDs are going to be in a 5x10 array. It still can be done otherwise though.

I personally would keep the Arduino attached to the Mac and send commands that way. Attaching a wireless card to the Arduino is very difficult to program with and it just exponentially increases the difficulty of the project.

I would have to agree with this. The Wi-Fi interface will take much more work than the rest of the project; it isn't worth it.

LtRammstein
Jun 26, 2009, 11:30 AM
Well, there are many ways on hooking up 50 LEDs together.

Easiest way would be a matrix (25x25) then sending row and column commands to some circuitry. From there you can have biasing resistors and transistors for controlling voltage/current flow to each LED. It's a bit more time consuming, and you can make it expandable.

Plus, LED technology has gotten in such a way large power-hungry LEDs are not necessary anymore. A friend of mine has a circuit board with 12 LEDs on it that are powered by the microcontroller and manipulated by the LED Driver. Plus, they are BRIGHT (350 mcd)!

But it's all on your design specs.