RGB Strip & Potentiometer. Blue /red / off

Hi there,

Just a quick heads up, i'm pretty much a novice when it comes to this sort of thing. Have just got hold of a few bits I think I shall need for my project.

Basically I have a small 20cm strip of RGB LED's.

I need to control this with a potentiometer.

Basically I want it to be a 180 degress turn. fading from Red to off to blue. (Off being at 90degrees)

I have an Arduino UNO experimentation kit, 10k ohm linear pot, 3 x TIP121 TRANSISTORS, RGB LED STRIP and a bunch of resistors.

Does any of this sound particulay difficult? Can anyone spot any problems I might have?

Do I need 12V? or can I use a 9V battery?

Sorry if these are silly questions!


This is what I have so far,

Would love some feedback and guidance. Want to get this wired up so that my friend can help with coding it.

3 x 10k resistors going from + to transistors 3 x brown wires going to - 3 x red wires to digital outputs 9,10,11

Where do the 3 RGB wires from the LED strip need to go?


Sounds like you have this - RGB LED, with 4 pins - one +, and three -, one for each color.
In which case you connect + to +5, and each - to an NPN transistor.
I suspect the strip has built in current limit resistors, can’t really tell from your picture.
Transistor Emitter has to connect to Arduino Ground for a common reference point.

Look again. He doesn’t have any base resistors.

Needs them tho.