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Topic: RGB LED and PWM pins does not work properly (Read 243 times) previous topic - next topic

Jymmy097

Hi everybody!

I have this image which describes the cables I've "attached" to my Arduino Mega to control an RGB LED.
I get something very strange:
when I write
analogWrite(RED, 0)
the LED becomes red and not set the RED component of the color to 0.
I'm a bit confused... :~ :~
If I write
analogWrite(RED, 255)
the LED turn itself off.
(in these examples, the others colors are set to 0. Really.... 0. They are not visible).

I have an Arduino Mega and I've connected the RED to 8, GREEN to 9 and BLUE to 10 and Ground to 5V port.

What is the mistake?

Thanks a lot!

Jymmy

AWOL

Common anode LED?
The behaviour you describe sounds perfectly normal.
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

Jymmy097

I've seen some tuts that explain that I have to set the colour with analogWrite(colour, 0 if I have to turn off that colour and vice versa.
So that seemed a strange behavior. To avoid errors, I post the image of my led here (it's attached!)

Thanks.

AWOL

If the LED is common anode ( impossible to tell from the photo) then the analogWrite sinks current, so the action of analogWrite is inverted - 0 turns the LED on full, and 255 turns it off.
If you want to write, say, 25/255 brightness, and a variable "brightness" contains 25, then analogWrite (redPin, 255 - brightness);
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

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