I downloaded the MacOSx Arduino program and started up my UNO. I immediately noticed that my L light was flashing. After a little bit of googling I learned that this is completely normal as the boards often come preloaded with "blink".
I set up my first test using pin 13. The simple LED blink test. I've wired much more advanced LED circuits so I'm thinking this should be easy... Except I'm getting nothing. I went back and followed your tutorial exactly, still nothing. The exact same setup works on my Raspberry Pi so I'm at a loss.
I know I can write to the board as changing the delay time works flawlessly with the hardwired LED for pin 13. I've tried multiple LEDs, Tested the resistor, and even tested the output of the pin with a multimeter( I know it won't be accurate but it does prove it is switching from high to low).
Everything appears to be working but the LED won't come on. Is there a trick other than this Simple LED test to determine if the pins are working?
Thanks in advance for any assistance!
Edit:
I'm fairly certain that something is wrong. I get a voltage change but it is tiny. I'm shifting between .012V(low) and .023V(high). I tested the same circuit on my Raspberry Pi and I'm getting a steady 1.805V (high).
This is my first Arduino board. Is it possible there is a setting or step I missed that could be causing this? I'm getting these numbers straight out of the box.
Hey everyone, Thanks for the replies. I'm fairly certain that I have everything set up properly but just in case:
I've got a ground (3rd up from bottom of power pins) connected to my negative rail on the breadboard. I then have digital i/o pin 13 connected to the positive terminal of the LED. Next I connected a 330 ohm resistor from the negative terminal of the LED to the Negative rail.
I'm using the default blink program modified to pause 5 seconds: (this will blink the L light on then off on 5 second intervals but not my led)
/*
Blink
Turns on an LED on for one second, then off for one second, repeatedly.
This example code is in the public domain.
*/
// Pin 13 has an LED connected on most Arduino boards.
// give it a name:
int led = 13;
// the setup routine runs once when you press reset:
void setup() {
// initialize the digital pin as an output.
pinMode(led, OUTPUT);
}
// the loop routine runs over and over again forever:
void loop() {
digitalWrite(led, HIGH); // turn the LED on (HIGH is the voltage level)
delay(5000); // wait for a second
digitalWrite(led, LOW); // turn the LED off by making the voltage LOW
delay(5000); // wait for a second
}
I can't see your image here at work (filtered).
If it's a breadboard, it might be the type with the "rail" that's split in the middle and you have power Gnd in one split and circuit Gnd in the other.
(Ohmmeter)
Looking at the photo, is the black wire connected to +5V? And the green wire connected to Grnd ?
I don't see a resistor in series with the LED (you need one).
It could also be that you have burned out the LED, if you applied 5V at 500ma. to it.
Still (after you put in a resistor), try reversing the LED first.
What do you mean, you "get a voltage change"? Do you mean you have a DMM connected to pin 13?
Try changing to a different pin. Are you sure that you have that wire plugged in to D13? I can't quite tell from the picture. Don't forget to change it in the code, too.
Oh, yeah, and learn "Blink Without Delay" as soon as you can. Using delay() to do -anything- sucks. I wish that example wasn't even in there.
Backwards would be my first guess too. Can you light the led directly from the arduino 5V pin instead of pin13?
Still (after you put in a resistor), try reversing the LED first.
I just tried the 5v directly to the positive terminal on the led. It did not light up. I know that the longer end of the LED is the positive side. I also tried reversing the LED (it's a diode so this I know this wouldn't hurt anything). No luck... The same setup does work when powered By the Raspberry Pi.
Try changing to a different pin. Are you sure that you have that wire plugged in to D13?
Yeah I'm sure I'm in pin 13. It is just hard to tell with the black on black. I've tried this with 4 different pins (updating the code to reflect).
Looking at the photo, is the black wire connected to +5V? And the green wire connected to Grnd ?
No, the black wire is in the ground. You have to look at it in full resolution. You can follow the link and click on the image again in imgur to see it full resolution.
I don't see a resistor in series with the LED
If you look closely you'll see one. It is there.
If it's a breadboard, it might be the type with the "rail" that's split in the middle and you have power Gnd in one split and circuit Gnd in the other
I've tried a few different variations of the same setup. a few didn't use the rail.
What do you mean, you "get a voltage change"? Do you mean you have a DMM connected to pin 13?
I hooked a fluke 117 multimeter up to the circuit. I'm getting a reading of .012V(low) and .023V(high). The same setup on the Raspberry Pi reads 1.805V (high). it seems that the Arduino is significantly under powering the LED.
I first posted this to technical support because I am fairly confident in my basic circuit skills. They moved me here to project questions. I really do think it is a damaged board though. I can get a Rasberry Pi to power the circuit as is...
Yeah, True. Maybe not dead but the pins don't seem to be working. I've tried multiple wires, setups etc. The Multimeter is definitely reading a flat 0.00 coming from the 5v.