I just wonder, why I need to put one resistor in front of each LED and not simply use one R between LED GND and Arduino GND? Wouldn't that have the same effect? (borrowed picture shows how it's supposed to be) [image]

Do I need one R for each LED?

Grumpy_Mike September 25, 2012, 8:34am 2

Yes you need one resistor for each LED.

See