Arduino NG & Pin 13 problem

Hello all,

Just received my NG from SparkFun, am very anxious to get started. But, I have run into the most basic of problems. I am very new to Arduino, and microcontrollers in general, so I may be misunderstanding something or doing something very dumb. So I power up the board via USB, get the USB drivers installed, the IDE recognizes the board, compiles and uploads the led_blink example just fine. Problem is is that the LED that I hook to pin 13 & ground does not blink. Instead, a surface mount LED near pin 13 blinks. Change the code, upload it, and the smd led blinks as programmed, but not the LED in pin 13 :( I know the LED works (tested with a resistor & 5v supply on a breadboard), and I have flipped it in case I had the polarity wrong. Any ideas?



if the led on board blinks then the board is working properly

2 quick comments

first : there is already an led connected to that pin, if you add another one it might not light up properly.

second: if you are using an ultrabright led then the amount of current needed to turn it on cannot be safely provided by arduino and pin13 (because of the resistors and led on board) can not provide enough energy to light it up.

change your code so that you are not using pin 13 but ,say, pin12 then connect the led to a 270/330 ohm resistor and try... this way it shoudl work. you will need to build this circuit on a breadboard.


Have you tried putting the longer Pin (+) of the LED in pin 13? so basically changing it's polarity? Let me know if that helps things.


second: if you are using an ultrabright led ...


Hi Massimo,

This was exactly it. The LEDs I have handy are ultrabright blue ones. Did a quick test, and it works as expected off of pin 12 :)

Thanks for the fast reply, and for designing a great lil board!!~