Beginner Question. Digital pin current

Forum 2005-2010 (read only) Hardware Interfacing
1

Hello,
I recently started toying with the Arduino and I'm trying to make an IR transmitter for my camera. I've seen some posts here on this but mine is a bit different (than the posts I found) in that I'm using a 555 timer to generate the 40 khz signal. I'd like to connect the LED to the IC output (~2.3V) and then connect a digital pin to the other LED lead. I'll set the pin high most of the time to keep the LED off and then set the digital pin low to allow current to flow through the LED.

When I try this I can't seem to get more than a fraction of a mA to move through the digital pin. If I use analogWrite(pinout, low) I can get much more current (>20mA) draw. Is there some reason I can't get current flow into the digital pin when it's set to low? I know the IC is able to supply the current as I can power the LED if I connect to ground instead of the digital pin.

Thanks,
Scott

2

Did you do...

pinMode(YourPinNumber,OUTPUT);

... in the setup() function?

Intil you do that the pin is configured for input, and will be high impedence.

BE CAREFUL: The pin should not have to sink more than 40mA or it may be permanetly damaged. In your case, simply check the current that flows when you connect ((what WILL be connected to the Arduino pin)) to ground.

3

You are correct...and I am a little embarrassed. I was setting "A" pin to output, just not "the right" pin. Thanks for taking the time to reply and for getting me back on track.

Scott