Pin Assignments on RGB LED?

[bunger]

I bought a bunch of RGB LEDs from the Adafruit store, am playing around with them, and am having a difficult time. Specifically, the data sheet shows the following pin assignments:

--Flat Side--
Pin 4: Red
Pin 3: Anode/Cathode
Pin 2: Blue
Pin 1: Green

Using these assignments, I can't get the LED to light up. I can only get it light if Pin 4 is connected o Ground and Pin 3 appears to be Red. Not sure of the other 2 assignments as I can't yet get them to light.

Am I missing something stupid here?

Thanks
Bill

[adafruit]

what part number are you referring to?

[bunger]

I have bought the Diffused RGB 5mm LED 25 pack and bought them individually:

https://www.adafruit.com/products/159

https://www.adafruit.com/products/302

[pburgess]

Tell us about your voltage source. Wouldn't be a single AA battery, would it?

[bunger]

I have it connected to an Arduino Uno powered by the USB connection to my laptop. I have also tried it with the 9v power block that came with the Arduino Starter pack... same result.

Bill

[pounce]

You are using some resistors on the RGB legs before grounding? These are common anode which means you power the long leg and the others sink. Note the specs on the product page. (Red: 2.1-2.5V Forward Voltage, at 20mA current, Green: 3.8-4.5V, Blue: 3.8-4.5V ). You have the pins in the right order. Have you tried the tutorial?

[bunger]

No resistors.... And am following the tutorial....

[adafruit_support_bill]

No resistors.... And am following the tutorial....

Which tutorial? The LED tutorial examples here all use resistors to limit the current. Too much current can damage both the LED and the Arduino output pins.
http://www.ladyada.net/learn/arduino/LEDs.html

[bunger]

I just did some testing with a plain 'ol LED, connecting it to the various Arduino pins and it lights up without issues... so nothing is fried. I also have about 35 RGB LEDs and none of them work, so it is likely not a fried LED.

Sooo.... maybe something in the code is wonky.

Can someone post really stupid simple RGB LED code and I will test that?

By the way... THANKS ( that's a big "thanks" ) for all of the help!!
Bill

[pounce]

Resistors.

[bunger]

So there theory would be that too much power is getting through, thus preventing the LEDs from lighting? Seems like they would light up even without resistors...

[adafruit]

the LEDs are common anode, pin 3 is the anode
that connects to 5V
connect the other pins to resistors to ground

[bunger]

Apparently I am now totally confused.

I thought pin 3 went to ground followed by pins 1,2,4 going to various output pins ( ie., 9,10,11 ).

But you are suggesting that pin 3 goes to the 5v power source and pings 1,2,4 all get piped to ground? If that is the case, how do you control different red, green, and blue light levels?

Bill

[adafruit_support_bill]

how do you control different red, green, and blue light levels?

Connect the RG & B cathodes to Arduino pins (using current limiting resistors) and when you do a "digitalWrite(LOW)" it will pull the pin to ground and light the led.

[bunger]

Connect the RG & B cathodes to Arduino pins (using current limiting resistors) and when you do a "digitalWrite(LOW)" it will pull the pin to ground and light the led.

Humbly bows before you, accepts his dunce hat of Newbieness, and greatly appreciates the help!!!!!