Something Odd on the UNO

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oldsubsailor
 
Posts: 3
Joined: Tue Dec 18, 2012 11:56 am

Something Odd on the UNO

Post by oldsubsailor »

I am playing with the blink sketch, and have three LEDs blinking on different pins. What is odd, is that pin 13 produces a bright LED, while the other pins are much dimmer. I am using a 330 ohm resistor on each negative leg.
I am using pens 13, 12,& 8. I have also tried using my mac book pro usb and a 9V battery for power supplies.
Any idea as to what is going on here?

Thank you,
OSS

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westfw
 
Posts: 2008
Joined: Fri Apr 27, 2007 1:01 pm

Re: Something Odd on the UNO

Post by westfw »

Did you remember: pinMode(12, OUTPUT) in your setup() function ? Without that, the digitalWrite() will switch the "pullup" on and off, but not provide full "drive" on the pin. This can cause dim flashing of LEDs.

oldsubsailor
 
Posts: 3
Joined: Tue Dec 18, 2012 11:56 am

Re: Something Odd on the UNO

Post by oldsubsailor »

Ahhh,
Thank you westfw, I missed that in the initial Blink program; should have printed it out.
You solved my concern. :D
Thank you,
OSS

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