Starter Kit Project #15 optocoupler

[StewieStew]

I'm trying to gain a better understanding of optocouplers. In my project, I am attempting to use an optocoupler to activate a pushbutton that will power an LED (the LED and pushbutton simulate a separate circuit). Once the Arduino powers on, the LED lights up successfully for three seconds before powering off, and never turning on again regardless of the delay values I input into the program. If anyone can explain what exactly is happening I would greatly appreciate it.

[pwillard]

You only activate the Optocoupler LED for 15ms and you expect to see it? Maybe you need to turn on that LED a bit longer... like 2 seconds...

Note to all: USE DRAWINGS not photos of your "air wires". The pictures are almost useless as a reader will run out of patience trying to figure out what your intentions are.

[groundFungus]

I don't see a current limit resistor for the LED.

[Paul_B]

StewieStew:
Once the Arduino powers on, the LED lights up successfully for three seconds before powering off, and never turning on again regardless of the delay values I input into the program.

Hmmm. You don't suppose that is because you have it connected to pin 1 of the Arduino instead of pin 2? This is the Tx pin, activated while Optiboot waits to see if you want to program it, then shuts off until you activate the serial interface.

groundFungus:
I don't see a current limit resistor for the LED.

I do.

[TomGeorge]

Hi,
Welcome to the forum.

Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html then look down to item #7 about how to post your code.
It will be formatted in a scrolling window that makes it easier to read.

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
Currently it is hard to see the orientation of the Opto and LED.

Just as you have a current limit resistor on the input to the opto, you need a current limit resistor in series with the LED.

As has been pointed out the delay(15), is a delay of 15ms, try delay(1000), it will turn the LED on for 1000ms or 1Second.

Thanks.. Tom..

[StewieStew]

Yup this fixed the issue, *Slaps face

[/quote]

Paul__B:

Hmmm. You don't suppose that is because you have it connected to pin 1 of the Arduino instead of pin 2? This is the Tx pin, activated while Optiboot waits to see if you want to program it, then shuts off until you activate the serial interface.
I do.