Weekend Mini-Project: Headphone Splitter
Sharing music is fun. Sharing earphones is not. That's why when I was taking apart an old iHome and noticed it had two headphone sockets, I immediately saw a headphone splitter in the making. A headphone splitter plugs into an audio socket and splits the sound into two sockets so that two sets of headphones can be plugged in and listen to the same sound.
It doesn't matter that one was labeled an aux in and the other is an aux out; they're the same socket.
A couple tests showed that each socket had a center ground pin and right and left pins on either side. By connecting the corresponding pins together, I could make them both output the same sound. I also had to murder a pair of cheap earphones to get the headphone jack and wires from it. There should be two rubber sleeves coming from the headphone jack. Each houses a signal wire (one had the right stereo and one has the left) and a ground wire. These are covered with enamel for insulation against each other, so that must be scraped off first (I used an X-Acto knife). The next step is to solder the signal wires to the left and right pins on the sockets and the ground wires to the ground pins.
To mount it all up, I soldered the components to a perfboard. Then to insulate the small, fragile wires from both short circuits and mechanical vibrations I covered them with hot glue. The whole affair, less than 4cm long, was then placed inside a mini altoids mint tin. I drilled two holes in the front for the sockets and cut a slit in the side so that the headphone jack could either be wired through the slit or stored inside the box. The result is a cute, compact, and useful package.