I'm new to electronics so any helpful advice or resources would be greatly appreciated. I built a USB switch to connect my keyboard to two PCs using a 4PDT switch and it works great. Now I'm trying to add LEDs to indicate which PC is connected. I added LEDs in the manner this diagram illustrates only using the switch above instead of a rotary as shown.
My problem is both LEDs are powered in both switch positions (A/B). Why would this be the case when the LEDs are connected to power from separate USB connections and only share the ground? What can I do to correct this behavior and illuminate only one LED based on which switch position is selected?
Here are some images of the circuit. Helpful comments welcome, but I know it's an ugly prototype. You will note the resistor through hole N07 is purposefully disconnected until I can wrap my head around the issue.
Best Answer
It looks like the LEDs are powered from the computers - the +5 V terminals on the computer USB ports supply power to whatever device you plug in, so the LEDs will have power regardless of the switch position.
You would need another pole (or two) on the switch to control the LEDs.