How to close the contact of the control button using an optocoupler?

Question

Do it yourself

Hello, I need to close a tactile button on a home appliance using a galvanically isolated device. There is an optocoupler with an NPN transistor (817C). I want to know how to do it right. Am I correct in understanding what I need?

0) Solder the conductors to the button.
1) Measure the potential at the contacts of the button.
2) Correctly connect the optocoupler transistor (emitter to "minus").
3) Solder to the "diode" side and bring the wires out.

From the side of the control diode there will be a voltage of 5V and a 100 ohm resistor. I'm new to this stuff, I want to make sure I don't burn anything. Thank you!

Answer 1

The resistor on the control side can be taken 510 ohms. The rest is good.