hi
im trying to switch a +5 to a pin on a auduino project, the switch circuit is in a very noisy environment hence i using an opto isolator, first time ive used one

have i got my circuit correct? ive limited both led and current to the ic pin to 10ma

thank you

 

You don't have the circuits seperated, so the opto doesn't accomplish much.

 

The way you have that laid out, the "+5 volt to pin" is always at +5 volts. I think you need to move the 560r to the top of the transistor, not the bottom.

The result would be a reversal of the logic. If this is not good, explain your wishes better and we can work something out.

 

ok i think ive got it now ive revised my circuit

just wondering if there is any way i could use the + and gnd in my circuit, for the (opto part switch)

and isolate that from the rest of the circuit?

thank you

 

That will work.

 

I'd suggest increasing the pullup resistor on the collector. A 560 ohm resistor will draw nearly 10 mA from the 5V rail when the optocoupler is activated, which is a bit wasteful. A more typical value would be 10k.

If you want to interface to an electrically noisy environment, I would suggest using series resistors of 1~10k in both of the wires that go out to the switch (which I assume is in the noisy environment) and a capacitor of say 10~100 nF from the microcontroller input to ground. You will lose the electrical isolation, so there's no reason to use an optocoupler.