Can you help me I have a problem, this program :

  • Blink
  • The basic Arduino example. Turns on an LED on for one second,
  • then off for one second, and so on... We use pin 13 because,
  • depending on your Arduino board, it has either a built-in LED
  • or a built-in resistor so that you need only an LED.

int ledPin = 13; // LED connected to digital pin 13

void setup() // run once, when the sketch starts
pinMode(ledPin, OUTPUT); // sets the digital pin as output

void loop() // run over and over again
digitalWrite(ledPin, HIGH); // sets the LED on
delay(1000); // waits for a second
digitalWrite(ledPin, LOW); // sets the LED off
delay(1000); // waits for a second

it says that the input pin is 13, ok, but I don't see the output pin, WHERE IS THE OUT PUT PIN???
Lets say, I connect the positive(longer ) wire of the LED to pin 13(the input pin), and the negative (shorter) wire to what pin, what output pin???


Picture of Arduino
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D5quar37 years ago
checkout on the bottom of the Arduino page it has some cool tutorial videos it really helped me
D5quar37 years ago
Output pin is pin thirteen because it outputs the voltage
alvinx9 years ago
as you see in the picture all the pins are labled on the board, and pin 13 is the pin next to the GND pin labled as 1 on top and 3 on the bottom. And you do not need a resistor for pin 13 as it already has a built in resitor, therefore for connecting the led, connect the positive end to pin 13 and the negative to GND and it should light up. Pin 13 is also connected with an led on the board so the led on the board should light up simulteneously. Hope it helped. -Alvin
comodore (author)  alvinx9 years ago
Thanks, It helped! :)
gmoon9 years ago
On the "official," fully-compliant Arduino boards, an on-board LED is permanently connected to output #13.....which explains output #13's use in the demo.

Here's the Diecimila schematic--the LED is wired to output 13 through a 1K resistor.

If your board doesn't have a built-in LED, connect one externally exactly like the above schematic.... (#13 -> 1K -> LED -> GND.)
gmoon gmoon9 years ago
Reread the source code--there isn't an input. It blinks pin #13. You do see pin 13? It's right beside the pin labeled GND. The picture you're using has some drawn reference labels, but that's for OSC (Open Sound Control) protocol, not a general Arduino reference...
comodore (author)  gmoon9 years ago
OOOO, well that explains a lot, I was confused, didn't understand well, but now i do , thanks a lot, if I have more questions about the arduino, can i PM you or ask you here on the forum? Thanks
gmoon comodore9 years ago
PM or forum is fine. You'll get more opinions on the forum, however. I've done a bit of work with the AVRs (the microcontrollers that the arduino are based upon), but instrutable user westfw is the go-to person for Arduino info.

Contact him for info on the Arduino programming language, especially...
comodore (author)  gmoon9 years ago
Ok, I will bug westfw whit my questions, haha :) Thanks!
westfw comodore9 years ago
Oh my; someone mentioned my name, and Arduino, and I didn't notice...
As someone said, this looks less like an actual Arduino question, and more like a question on "conventions of electronics circuits." Usually, unless specifically noted otherwise, one lead of a "device" connected to a microcontroller will be connected to a microcontroller pin, and the other pin will be connected to "Ground" for the circuit.

In the case of the LED Blink example that uses pin13 as an output, there is a convenient GND socket right next to the pin13 socket, so you can plug in an LED really easily, As shown in this tutorial

Pre-"diecimila" Arduinos (such as yours, which looks like an "NG") have a built-in resistor on pin 13, so you shouldn't need any parts other than the LED. Diecimila and later arduinos tend to have a built-in LED on pin 13, so you don't even need an LED to do the basic testing/tutorial. In any case, it seems to be relatively safe to drive an LED from an Arduino pin without any resistor, although it has to remain "officially not recommended."
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