I'm looking for a way to control RGBW LEDS. In past projects, I've used this Picobuck driver from Sparkfun With it operating off of 24VDC, I could have 5-6 LEDS in series of each color. But with this method, I could only control the dimming of each color collectively.
In my next project, I'd like to have about 6 CREE RGB or RGBW leds in separate locations, each about 6-10 feet away from my arduino controller. See attached photo. So there is 1 RGBW led at each station, and I need to dim the 4 colors at each station separately. If I have a Picobuck at each station, I will need something along with it to do the dimming. And then how to communicate between it and the arduino hub? I could have an Atmega328P-AU at each station (overkill) which could then dim the 4 channels, but can the Atmega328 chip at the hub communicate with 6 other Atmegas, at 6 feet away?
I thought I first an I2C expander would be perfect. The Arduino can talk to 6 I2C expanders, the expanders could have 4 PWM outputs doing the dimming of the 4 colors. But it looks like I2C doesn't work at that distance.
you could use hc05 or similar bluetooth modules as slaves at each location and one on arduino as a master or xbee stuff wireless receiver transmitters there are tutorials on these
A 16-channel I2C PCA9685 breakout board (ebay, Adafruit) can control (12-bit PWM) four RGBW LEDs.
You can theoretically connect up to 60 boards to one Arduino.
I have two boards running 24/7 about 6meters away from the Arduino over Cat-6.
The PCA9685 controls CC LED drivers, similar to those PicoBuck drivers.
That many LED drivers can be expensive, so I designed my own PCA9685 board that includes the 16 LED drivers.
Leo..
Wawa, that's great to hear that you don't have trouble at 6 meters. I saw those I2C chips at Adafruit and thought they'd be perfect if they would work at that distance. I see you led drivers use a different chip. Would you have the eagle files for that board?
Thanks.
xm-l rgbw leds.
The datasheet says 1 amp current per led die, but I overheated a couple for lack of large enough heat sink when I ran 2 of the 4 colors at 1 amp.
I have ample heatsink now, but I still wonder how much total current is a safe amount? The leds are mounted on a 20mm star board, which is attached to an aluminum block using some adhesive tape made for that purpose from DigiKey. The Aluminum block is setting in water so it won't get hot, but I wonder about the chip itself -- how fast it can dissipate the heat unto the star... I think I'll stick with 1 amp max total current on all 4 colors.
