Hello! I have a quick question for everyone. I am wondering how many LEDs and Arduino board can individually control. When I say individually control, I mean the color and brightness of the LED.
Long story short, I am interested in making a similar project that I found on YouTube. I can't post the URL as this is my first post, but if you search "64 LED table wave", it is the first result or check my next post.
Can someone give a new guy some tips and pointers of where to start? Thanks!
yep, basicly on chips like these you plug your led's into + and let the chip control the - which lets you individually address each LED and its brightness via pwm
TLC5940 is really good and probably easiest way, however they are very expensive. I personally like to use 74hc595 chips and multiplexing, they are cheaper and you can control allot of leds, In one project I control six 8x8 red/green led matrixs at 4bit color depth whit only one atmega168 and 13 595 chips, that's a total of 768 leds. However there will not be much cpu time left for other processing.
74hc595's are made for logic level signaling, at a usuall absolute max of 20ma on each output you wont be driving leds very bright, depends on your application
If you just want led's to light, or if you want to be able to see them in daylight, for example
as far as chaining them, I am not sure what the max would be, I am pretty sure its a lot
I am not looking to power an amazing number of LEDs. Maybe 128 or so, and being able to see them during the day is important. I want them to be bright!
yea you can mix those, problem is, most conveniently packaged driver IC's including the ones on page one control the cathode (connect and disconnect to ground) , and those led's linked are common cathode (all 3 led's in the package has ground are tied to 1 wire), to go that route you would need common anode ( one + leading to 3 independently controlled grounds)
If your going to make your own solution from scratch, it doesnt matter... BUT if you want to use a driver IC almost all are setup to flip on and off the cathodes, and not the anodes, so you would need a common anode led in most situations
super you just multiplied the complexity
3b) no it would be up to what you have driving the led's, for example...
looking around recently showed some maxium surface mount chips that could drive 2 arrays of 64 leds, and provided 4 levels of "brightness" so 6 of these jokers (at 8 bucks a peice, + smt board development) could run a 128x128 rgb array with upto 64 unique colors by themselves (4 ^3) the same could be achieved by 3 of the TLC5940 per bank of 16 rgb led's, depends on resources and scale I guess, with enough of both you could drive a 16.7 million color HD jumbo-tron if you wanted (in low draw resolution)
on the flip side, if you had a beefy power supply and a clever way to hook it up, you could make a 3'x3' "mood" table
Just to add another dimension into the mix.
You can multiplex the TLC5940, I have done this on a four times basis. That is expanded the capability from 16 LEDs per chip to 64. That means using 3 chips you can have 64 RGB LEDs. http://www.thebox.myzen.co.uk/Hardware/Mini_Monome.html
Am I misunderstanding how RGB LEDs work? I thought that if you were to illuminate the red portion as well as the blue portion it would "create" a new color, in this case purple. If you were to mix the various colors and brightnesses, you would produce many different colors. Am I wrong?
no your right, but how much your able to mix them is a function of what your using to drive them, and not necessarily the led
If you were just to turn on red and blue, you would get purple, but maxing out at about 6 unique colors
if your able to half turn on red and fully turn on blue now you have a new shade of purple, but increased complexity in order to drive the red led (or whatever one) at 50%
Its a choice for you to make how many colors you want to have, and how much wiring your willing to put up with