DIY photocouplers

Here are a few pics of photocouplers I've been working with.  So far, I've only used a light sensitive resistor/LED combo, but I just ordered some photodiodes from Mouser, so we'll see...


This guy is very basic.  You can see the small (<1K) resistor on the LED's positive lead, just so I don't accidentally burn in out.

Here is a slightly more involved one.  I took a small section of toilet paper tube, glued a mirror to one side, then positioned the LED opposite the mirror and two light sensitive resistors on either side.  Then, I sealed the whole thing up with electrical tape.