If the on-board LED works, then the board is unlikely to be broken.
You do know that LEDs are polarized devices, don't you? Examine the case - one side will be flattened off. Examine the legs - one will be longer than the other.
The leg that is on the flattened side (the shorter leg) has to go to ground for it to work.
ok, thanks for asking me the basic "is it plugged in" questions
but yes, it's a good LED, I tested with AA batteries (4.5v) and used a couple of different LEDs also. they all work.
so, I got 2 questions:
anyone have any code or other method for me to check the pin hardware?
if not, then is this pin defect a common or not unusual thing for the Uno?
I just don't want to have to waste time going to exchange this for a new Uno and would rather spend the time experimenting and studying more. It is a real killjoy that right off the bat my Arduino learning has hit such a snag, as you can imagine.
you mean ground? GND?
sorry i don't follow; how would it test it?
just saw your message on common ground. So I can try plugging it into the OTHER GNDs on the other side (next to the analog pins)?
there are two additional GND there.
i will wait a few more hours to see if anyone says this is a good / bad idea (but thanks for the train of thought).
i got a 8 x AA pack but am a bit wary of sticking in 12v, maybe a 9v better? I need to rig that up though as I don't have the male jack into the female power on the Uno. you really think it's power source? because the tutorials all talk about this as the Hello World of the arduino and I can't see that the USB connector won't work with it, for a newbie blink tutorial.
It should work if powered through the USB (well mine did) try unplugging your power source and letting only the USB cable supply power as I think the board automatically switches . if you haven't tried that already.
Your arduino will be fine with 12v OR 9v.
To be honest I don't have any idea what it might be ... I'm just suggesting things which I would be trying. I've only owned an arduino for a month myself so I'm far from an expert .... but I do understand how frustrating these things can be.
thanks; your troubleshooting thoughts appreciated.
maybe someone with more experience can shed light to whether this is a common issue or maybe a "new" Uno needs to be somehow reset to allow voltage through the pins.
on another note i wonder what it would take to "repair" this kind of thing if I had to.
the CPU seems to work; i tested using some string code printing to the serial port. and the SMT stuff seems to work (at least the surface on-board LEDs, etc.).
You jumper pairs of pins together and it tests pins against each other (sets one to INPUT and one to OUTPUT and checks for proper communication). The jumpers are in dark red on the diagrams and not easy to see. Just connect 2 to 3, 4 to 5, etc. Skip 0 and 1 or serial I/O won't work!
by the way, when you say the serial won't work, do you mean that IF I connected those pins then it would be DAMAGED?
No, since one is an input and one is an output. If you connected to output pins, one driven HIGH and one driven LOW, you'd likely break something.
Actually, connecting the two serial pins together is a fine way to test the serial code. Just do a serial.write('a'); and then serial.read(); and hope you get 'a' back (but it's hard to see since you can't send anything to your computer!)
alohaduino:
The on board LED blinks. I changed the delay, etc. and it works.
However, pin 13 output does not seem to output anything.
The LED plugged into GND and pin 13 does not blink.
What LED? Can you show a photo of what you are doing? Not just a stock photo.
If the onboard LED blinks, clearly the processor is working. So you don't have a dud. Conceivably there is a bad solder joint on one of the pins at the edge, but it is hard to imagine they are all bad. Have you tried, for example, pin 7?
I can't see that the USB connector won't work with it, for a newbie blink tutorial.
alohaduino:
ok, thanks for asking me the basic "is it plugged in" questions
...
but yes, it's a good LED, I tested with AA batteries (4.5v) and used a couple of different LEDs also. they all work.
Can you describe this test in more detail? What value resistor did you use?
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Attached are some photos:
The basic code.
The LED attached to 4.5V battery pack. Lights up.
The Uno with LED (external LED not up, on-board lit up).
The Uno with the pin 13 and GND connected.
(I tried both polarities by the way, in case the photo is the wrong way).
