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RGB LED interface with arduino Answered

I need to drive 5 3W RGB LEDs in series using an arduino. The maximum current required is 350mA each for R G and B dyes.
and minimum current requirement is 2.4V, 2.4V and 3.5V respectively.

What should I use to interface the LEDs with my arduino as the output current of each arduino pin is 50mA maximum

Thanks in advance

2 Replies

nomuse (author)2014-03-15

The brute-force version is to switch the LEDs with power darlingtons, and stick a hefty half-watt ballast resistor on each LED.

A better solution is to use a constant-current regulator. There's a cheap regulator made for HR-16 lighting fixtures, based around the PT4115 chip; you can find those cheap at the discount suppliers: http://dx.com/p/internal-constant-current-source-p...

The cute thing about these is, the PT4115 has a PWM pin (not used in the cheap constant-current drivers). You can solder a whisker to that and you've got your LEDs.

I'd also caution that the Arduino's power supply won't want to do this kind of heavy lifting either.

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mpilchfamily (author)2014-03-06

You will need a driver board for each LED.

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