I'm trying to figure out how to control 10 Luxeon Rebel LED (700mA) from a Raspberry Pi. I want to be able to turn them on and off from code, but I don't need to have two or more LEDs turned on at once, always one LED at a time.
First of all, I don't know much about electronics, so that's why some questions might seems obvious. I did some research and before ordering all the parts I would like to know if I made mistakes.
I plan on using this BuckPuck Driver to drive the LEDs. I though that I could put the LEDs in parrallel, and use a 2N2222 transistor as a switch. Is that the best way to go ?
To find the value of the resistors R2, R4, R6, etc, I used the gain found on the datasheet (30), and the base emitter value (0.6V/1.2V). The GPIO of the Raspberry PI being 3,3V it's 3.3 - 0.7 = 2.6V and 23.3 mA = 111 Ω. Is that correct or do I misunderstand something ?
Do I need a resistor between the LED and the transistor, and if I need one, how do I found the value ?
Finaly, I would like to be able to dim the light using PWM, it seems to be feasible with the CTRL and REF pins of the BuckPuck, but I don't really understand how it works.
Here is a schematics showing only three LEDs (with 10 LEDs the image was too small).
Thank you !