# 2000 LEDs

Hi,

I’m making a project and I need to control about 2000 leds using arduino. Is it possible? Or is there a maximum of LEDs I can connect to the board?

1mpar

That depends on whether you would like to control each individual LED.

2000 LEDS would also require an additional power amplifier.

A "normal" (not Mega) Arduino contains 14 digital I/O pins. So you could operate at most 14 LEDS with these.

Or is there a maximum of LEDs

I don't think the Arduino can control more than 1999 LEDs ;D

Have a look here:

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1239931051/5#5

7^3 = 343 LEDs. Check out the amount of external circuitry (nice job though)

What I want to do is connect about 100 leds to each analog output, so the arduino mega could handle the values.
My doubt is if one single arduino could provide power to all these leds. And how I can calculate the electronics.

The Arduino doesn't have any analogue outputs. It has six PWM output pins, so if you want to control 100 LEDs per PWM, that's only 600 LEDs. The Mega has 14 PWM pins, so still only 1400 LEDs. However, no reason not to control, say 140 LEDs per PWM, but you're going to need a big supply and some external transistors to switch them.

You don't say what type of LEDs you're thinking of using; LEDs can take from a few mA each to many hundreds of mA.

My doubt is if one single arduino could provide power to all these leds.

No way, the arduino can only source 200mA of current maximum. Anything extra and you have to go with external drivers. Please read the playground articles.

Two thousand is a lot of LEDs, more than I think you know. Scale things back a bit until you get a bit of knowledge. Try 16 LEDs to start with, I am sure you will find it a greater challenge than you think.

You can do 64 LEDs relatively easily using row-column scanning from a regular Arduino. I did an example with 128 from a Mega recently, and the code could be ported to the Duemilanove or earlier by only changing the pin numbers and losing one of the matrices. Here it is: http://www.tigoe.net/pcomp/code/category/arduinowiring/424

You can use the TLC5940 chip to PWM multiple LEDs, and you can daisy-chain multiples of that chip to control even more. You'd need to power the chip separately, but that's not too hard. Check out this example in the PLayground: http://www.arduino.cc/playground/Learning/TLC5940

You can also control multiple LEDs with a shift register if you don't need to fade them. Here's an example: http://www.arduino.cc/playground/Main/LEDMatrix

There are some other ways as well. I have an example with a multiplexer in "Physical Computing" chapter 14, and I'm working on updating some of that for Maker Faire this year, so hopefully I'll have that in Arduino code in the next few weeks.

AWOL, that's what I needed to know, that I'll need an external power suply.

Grumpy_Mike, Ill take a look at the articles.

In fact, the project is rather simple. I need to make a flower with a gradient of light on its petals. I'm thinking about using so many leds just to make the image smoother and brighter.

If i understand what your saying is... your making a flower out of LED's as in just making an image out of LED's... your going to change the color of the flower by different colored LED's right? So your not actually programing the LED's to go on or off or anything... just stay on..... so why don't you just design your flower out of LED's wire it up and design a power supply to run all of the LED's.

From what i understand your saying is there just going to be lit LED's not flashing or animated or anything just a static image made of LED's. If so why use the Arduino to run them? Just use a power supply.

tlavite, I need to fade the intensity of the leds according to a sensor input. There will be 2 buttons. One lightens it up and the other makes it darker. That's why I need to use arduino.

But I can make an external circuit with all these leds and than just output the 14 PWM outputs form mega to control each strip of leds.

That picture makes it clearer what you want to do, thanks. What size LEDs are you going to use? I would suggest that before you launch into making this that you make a small scale one first. With just 1 petal and 1 LED per zone. By my count that is just 14 LEDs and that you restrict the current to 10mA per LED. This will allow you to just control the LEDs direct from the Arduino and give you an idea of the wiring involved. It will also let you get started on writing the software.

Then I would make this design up one petal at a time at full size. Or maybe one PWM zone at a time. Test each stage thoroughly before going on to the next and build up your confidance and skill

Best of luck.

thanks, mike

I think it will be the best way too.

I'd made other arduino projects before, but none of them involving so many components.

You can have a look at some of my projects on the links below: http://vj.1mpar.com/arduino.htm http://vj.1mpar.com/therementos.htm http://vj.1mpar.com/drum.htm