CircuitGeek

You’re still frustrated with your old-fashioned and limited functions potentiometer? Instead of being annoyed by it, why don’t you spends several hours and make a DS1803 digital potentiometer?
With this DS1803 digital potentiometer, you can easily control the resistance over its range in the programmable action, and then send it commands over a 2-Wire (12C/TWI) serial [...]

Do you having trouble to pass the signals in between two circuits and you’re looking to overcome this matter? Stop right here, as you have find the permanent solution for the above problem.
All you need here is a good Opto Isolator v1.0. This little fellow allows you to pass signals from circuit A to B [...]