Audio Output Selector
Using my headphones with my computer is frustrating. Whenever I want to use my headphones, I have to move my computer so I can access the back panel, unplug my computer speakers, and plug-in my headphones. Okay, maybe it isn’t that difficult, but is should be easier. How about a device that allows you to select between headphones or computer speakers?
Solution
After some careful thought, I realized such a device could be implemented using three 3.5mm jacks and one dual-pole dual-throw (DPDT) switch (see the schematic below).
As you can see, the DPDT switch simply selects whether the input is connected to the headphones or the computer speakers.
Other Possibilities
A similar device can be implemented using two dual-pole single-throw (DPST) switches. This would allow the user to select headphones, computer speakers, or both. A much more sophisticated implementation might include operational amplifiers allowing the user to adjust the gain on each output.
22. October 2009 at 7:18 pm :
jackpot. this is so cool!
23. October 2009 at 12:48 am :
You can always adjust the gain passively by just using a potentiometer. An op amp would be nice for boosting signals though. You could also just use a SPDT and leave the grounds connected together at all times. Nice work! I need to make one of these.
23. October 2009 at 9:18 am :
@jared
I like the idea of using a potentiometer to passively adjust the gain. Usually I have the maximum gain at the output of my PC which is good for my computer speakers, but bad for my headphones. The potentiometer would allow me to passively lower the gain for the headphones while delivering the maximum gain to the speakers.
Unfortunately you have to use a DPDT switch because it is a 2-channel stereo signal. Even with the DPDT switch, the grounds are connected together at all times. Thanks for the comment!