Interfaces for LED packages

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jasonwebb
 
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Joined: Sat Sep 10, 2011 2:15 pm

Interfaces for LED packages

Post by jasonwebb »

I'm working on a simple Bluetooth-based LED controller project, and I'm trying to maximize the number of things that can be connected to it. I have built in support for driving up to 2 RGB LEDs directly using 6 PWM pins. I know that some LED modules like the BlinkM use I2C, so I'll break those out as well.

I don't have much experience using LED strips, what kinds of interfaces do they use? SPI? Direct IO? It appears that the addressable RGB LED strips offered by Adafruit (https://www.adafruit.com/products/306) and Sparkfun only need two digital IO pins, and they can be any digital IO pins. Are there any other types of interfaces I should think about?

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pburgess
 
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Re: Interfaces for LED packages

Post by pburgess »

The LED strips and strands indeed use two pins. The protocol is similar to SPI, except there are no explicit select or latch signals, it's all conveyed through the data stream.

The Texas Instruments TLC5940 is a popular LED driver chip for Arduino projects because it's available in a through-hole breadboardable version, and there's a library or two already floating around. That might be one worth pursuing.

mtbf0
 
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Re: Interfaces for LED packages

Post by mtbf0 »

i like software pwm on 18 pins. drives 6 rgb leds and still leaves rx and tx available for your bluetooth. did it once, (no bluetooth, though), but don't think i ever posted the code anywhere.

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