Optocoupler help

I think I'm having a hard time understanding how an optocoupler works. I made a circuit based on example 15 if the Arduino projects book, but instead of trying to hack a button, I'm trying to just light an LED on either side of the optocoupler. But, I guess I'm misunderstanding how this should work because the LED i'm trying to light doesn't light.

Below is a link to a youtube video I made. It shows the circuit. You can see the blue LED which runs from pin 2 of the optocoupler into ground lights up, but the red LED (which works, I verified) which runs from pins 4 to pin 5 of the optocoupler does not. I was under the impression that if I emitted high from the arduino to the pin 1 of the optocoupler through a 220 resistor (mine is 270 actually) and provided a path to ground that the optocoupler would be switched on and I would get current and ground from the pins on the other side.

Any suggestions - what am I missing?

My circuit:

Pin 4 to Gnd.
Place the LED and its series resistor between +5 and pin 5.

(The output of the coupler is not like a solar cell.)

Hey thanks for the reply, but I don't think I follow, wire pin 4 back to ground? and then have the red LED and resistor running from 5 to 4? What's 5+? 6?

Re: Comments - the project book is titled the Arduino Project book. It comes with the Arduino Uno starter kit.

Re: Schematic - yea, I'm not quite at making those yet. Next time :frowning:

Re: The answer -

I just figured it out, soooo...silly me. Optocouplers don't supply their own power. They're just a switch. So in the example video above there is nothing powering the 2nd LED.

The working model with both LEDs lit is here: Optocoupler correct - YouTube

This link was super helpful in case anyone else stumbles on it: Learning to Use an Optocoupler or Optoisolator