I want to use the output from my pi to act like a basic switch to an external circuit. I have wires rigged up to the pins on my motherboard and previously used a mobile phone to complete the circuit and thus switch the power on (I did this via the mobiles speaker terminals). Is there an easy way to do this? I do not need any power output from the pie, just to connect the two sides.
Apologies if this is a really stupid question but I am incredibly new to this stuff and when I searched, the answers I found were more complicated than I thought they should be.