How do you control RGB LED lamps? | |
Hi, I was hopeful that someone can point me in the right direction as to the basics behind the control of RGB LED lamps. Is it a matter of varying the voltage supply? Varying the polarity? Modulating an AC current over a DC supply? Any advice would be greatly appreciated. duBe
Answers:
From: Big Ed
hum, most have multiple pins. One for each anode and a common cathode. Some have reverse voltages for each color or built-in IC's with flasher or color cycles, red to ble to green. Beware as Red led usually require current limiting resistor and run at 1.5v vs. 3v for blue/green.
read spec sheets. use of modulation or PWM controls would simply use multiple LED's and not RGB versions all contained on one die.
From: Christopher
If you LED has 4 pins on it, it is probably as Big ED said, a common cathode and 3 anodes, or possible the opposite. To vary the brightness, use PWM (pulse width modulation) on each color. there are plenty of led pwm circuits available online. some of the simplest use a 555 timer chip. google for "pwm 555 led" or "pwm 555 led circuit" (or try 556 instead of 555) to find some.
Note that pwm to vary the brightness of an LED has a much faster rate than other PWM signals. if its on a 555 or 556, you can vary the values to make it fast or slow.
If you have any more questions, please feel free to email me at slithytove2 at gmail dot com
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