Hi to everyone. First of all I would like to say hello, since I'm new in this world. And also excuse me if I post in the wrong section.
In the project I'm working on I need Arduino to control (simply ON/OFF, no dimming at all) 18x 1w coloured HPLEDs and 2x 3w white HPLEDs in order to provide the right light to my young Saguaro Cactus.
There are 2 LEDs for every colour tonality: 2xBlue1, 2xBlue2, 2xGreen, 2xRed1, 2xRed2, 2xRed3, 2xInfraRed1, 2xIR2, 2xIR3 and all of them are 1w LEDs; 1xWhite1, 1xWhite2, both 3w LEDs. A total of 20 LEDs, but not every LED needs to be ON on the same time.
A RTC module determines when every group needs to be turned ON or OFF.
Blue1, Blue2, IR1, IR2 are groups that are always turend on.
White1 is on only on Phase1.
White2, Red1, Red2, Red3 are ON only on Phase2
IR3 has a special program, needs to be controlled alone.
Green is on request and may interact with IR3 special program, but that's not a problem.
All 3w LEDs (White ones) require 700mA, 3.2-3.4V
All 1w LEDs require 350mA.
All blues and green require 3.2-3.4 V.
All reds and IRs require 1.9-2.2 V.
My problem is: how to power the LEDs? Can I use the same power source for both LEDs and Arduino?
I thought to use an AC/DC 12V 60W converter to power them all and place the right resistor for every series of LEDs (2 LEDs in series of the same colour, all in parallel) and switch them using Mosfet IRF 540N. But this seems to be the less efficient way to wire the LEDs: resistors would waste a lot of heat.
I've made my researches and found some other way to solve the problem. One of these is using a ZXLD1350, but I don't know how to use it so I'd say no to it.
I've found this guide.http://www.instructables.com/id/Circuits-for-using-High-Power-LED-s/?ALLSTEPS
6th step seems to be quite simple and cheap to build.
Also I could use LED Drivers AC/DC or DC/DC.
Using AC/DC driver should force me to control it using a relay to turn on/off driver, right? If I have understood well, turning on an LED while its driver is on may burn it.
Going that way may become too much expensive, but I need to be sure to give the best life expectation to those LEDs...
I have found some Drivers and Power sources, but everything is getting too much confusing...
That's why I'm asking here
If more infos are needed, just ask.