Play/stop modded headphone adapter

[sjchiass]

I want to add a play/stop button to my headphones. I had a nice headset that did this in my office. :-(

• [X] Order part
• [x] Receive part in the mail
• [x] Research how to trigger signal to phone
• [x] Find a headphone jack to salvage
• [x] Build a prototype
• [x] Write about it

[sjchiass]

It's all explained here: https://source.android.com/devices/accessories/headset/plug-headset-spec

[sjchiass]

It ended up being a bit difficult to salvage a headphone jack (a.k.a. 3.5mm jack).

The headphone wires are very fine, so they can break under heat. They're also coated with an enamel or a bit of plastic. Stripping the coating with pliers or burning it off with a lighter won't work. The solution ended up being to pass the wires back and forth into a ball of molten solder atop an iron. The coating burns off into the solder (turning it yellow); keep replacing the solder until satisfied.

When soldering these wire, it seems best to use a smaller iron tip and lower temperature lead solder. Don't put too much solder. Try to spread out small amounts.

If you can avoid it, try to keep the wires instead of stripping everything down to the 3.5mm connector. You can melt the plastic inside the connector if you're not careful soldering wires onto it.

[sjchiass]

Making the controls is just a matter of attaching resistor values to buttons that short the (+) and (-) of the microphone.

[sjchiass]

My prototype isn't perfect, but I remember headphone accessories being imperfect too. You don't seem to get instant response from the buttons. It seems that volume buttons have to be held down.

If I had a scope, I would be checking the voltage signal passing through it. Buttons can bounce a lot. The phone might ignore that kind of noise (maybe it thinks it's static?).

[sjchiass]

I thought I was smart cutting up the protoboard before soldering it. I left just enough room to fit the buttons.

Turns out that wasn't a great idea. I had no room for wires! :-(

[sjchiass]

Oh... It might be a good idea to clean old protoboard before using it. I think the pads were oxidized. Solder would slide right off of them. :sweat_drops:

[sjchiass]

[sjchiass]