Homemade Optocoupler

[benobo]

Hello All,

I would like to make my own optocoupler, and I was wondering what resistance the photo-resistor should be? and what is the best color for the LED ?

Thanks for your time.

[Hides-His-Eyes]

The best LDRs in my experience are 1M dark, 20-40k light, but it depends on the intended application (there are 9 different models in the VTL series after all)

I think you're supposed to use yellow or orange LEDs.