I have a basic question that I am confused about how to make it.
I have Arduino Uno board, 8 common cathode led(LED - RGB Clear Common Cathode (25 pack) - COM-09853 - SparkFun Electronics)
I have to power arduino with 12v 1.5A adaptor.
Leds are seperated in 2 groups(4led-4led). Each group should be controlled by pwm pins of arduino(pin 3-5-6 for one group and pin 9-10-11 for the other)
I always used 5v pin to power before so now im confused what to do and if there is many rgb leds on a single pin. for 5 volt I used 220ohm resistor so should i use like 1K for each color of rgb led?
What should I do to make this circuit work properly. thank you
You need to drive each LED with a transistor, you can't drive 4 LEDs off one arduino pin, they will take up too much current.
Common cathode are not the easiest to drive with a transistor, you will need a PNP transistor in what is called a top switch. Emitter to the +5V collector to the current limiting resistor , other end to the anode of the LED. Cathode to ground. Then a 1K resistor from the arduino output pin to the base of the transistor.
Put your supply in the Vin jack and take the power from the +5V pin.
I got the transistors. It is working fine thank you.