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Topic: How can I Disable the Pin 13 on board LED? (Read 8474 times) previous topic - next topic

rtty21

Hello! I was wondering if anyone knows how to disable the on-board "L" LED that is is connected to pin 13 on the Arduino UNO?
(some of my prjects drive LEDs out of pin 13, and the on-board LED draws an annoying amount of current away from my LED disply.)
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Click the link to see stuff that I've built:
[url]instructables.com/member/rtty21[/ur

baum

Sorry, you can't. Try a different pin. Here's why:

Assuming you have an Uno or Duemilanove:



In the bottom left corner, you see "PB5" and 19. This is your pin 13. Then you can see where the arrow points; the LED is hardwired in to pin 13. Unless you have amazing skill at SMD soldering and you can take off the LED, you're stuck with it. I would just recommend a new pin.

Full schematic is here if you want it:

http://arduino.cc/en/uploads/Main/arduino-uno-schematic.pdf


ATMega is in the bottom right corner, the other microchip is the USB driver, I think.

Are all your other pins occupied?

Good luck!


Terry King

Hmm.. Current approximately 5 - 2 volts = 3 volts through 500 Ohms (The two 1000 ohm resistors in parallel)

I=E/R so .006A (6 ma)  .  Is that enough to worry about?? 

Looking at an UNO with good light and magnifier, the LED look pretty vulnerable to small cutting pliers.  And the trace to the Resistors would be easy to cut.. 

Up to you  8)
Regards, Terry King  ..On the Red Sea at KAUST.edu.sa
terry@yourduino.com  LEARN! DO! (Arduino Boards, Sensors, Parts @ http://yourduino.com

cjands40

Desoldering a two pin surface mount device (LED, resistor, etc) is pretty easy if you have two soldering irons or can borrow an extra from a friend.  Just touch both ends of the device for a few seconds and then lift with the device squeezed between the tips.

rtty21

------------------------------------------------------
Click the link to see stuff that I've built:
[url]instructables.com/member/rtty21[/ur

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