Hi - this is an amature question from a newbie. Hopefully this is the right place. Most headphone jack redirects the output from regular speaker to the jack when you plug in your headset. How does it do that? It is by means of simple mechnical switch inside the jack, or is it by detecting the current draw and triggering some relay switch? A bit background on what I am trying to do: my iPaq has only the headphone jack as audio out. I want to add additional audio out on the bottom of the PDA so that when i set it in the car cradle, it can hook up the audio directly to the car. I don't want to change the pin-out of the standard iPaq connector. So what I am trying to do is to expose the audio connection on the outside of the chassis via some tiny screws drilled in from the outside, and likewise for the cradle. The screws will make the physical connection. With that, I want this additional connection to turn off the whimpy internal speaker automatically similar to the headphone jack. Help is appreciated. Radioflyer
The way it most likeily works is that when the plug is inserted, it pushes a switch to cut signal to the main speaker. I don't think there is an easy way to do it without a headphone jack that has a switch build in.
Those type of headphone jacks have 5 contacts inside of them: left, right, switched left, switched right, and ground. When there's nothing inside of the jack, the left and right contacts are connected with the switched left and switched right contacts. When a jack is inserted, the connection between those four is broken, and the left and right contacts are connected with the plug that's been inserted. Your plan won't work with this setup. You'll need something else to manually switch outputs, like a small DPDT slide switch. This is how you'd hook it up: Code: P L S D e P A f k t L L O O O O O O P R S D i p A g k h R t R
It actually entirely software-based all soundcards since the beginning have had a little process running in the background that is just for that purpose. It's kinda wierd, but what are you gonna do?
padre...that's just wrong. First, this is a PDA we're talking about, not a full-fledged computer. Second, the software you're talking about hasn't been around since the beginning of sound cards, not by a long shot. Those apps require manual intervention to determine what's selected, because my sound card sure as hell can't tell the difference between a pair of headphones and 2.1 speakers using just the 3.5mm jack.
Thanks for all your input. It'll be hard to find a T(riple)PST switch for that size. Of course another option is to steal some of the unused connections from the iPaq bus. But maybe that's just too crazy...
