How to Make Accessories & AddOns for your Mobile (Cellular) Phone

Do you want to make an accessory or addon for your mobile (cell) phone? Here are links to HOWTOs, FAQs and manuals for headsets, ring tone amplifiers, chargers and more. If you have written a guide yourself (or if you know of tips and tricks not linked here), please submit a new entry.

Nokia 5100/6100	Adding an answer/end call button to a headset.
Nokia 5110/6110	A standard audio amplifier adaptor for the headset. A headset is useful device when you are outdoors. At home you may prefer speaking directly to the phone. But you can connect the phone to your hi-fi amplifier at home and play music on the line, record the calls, and use it as a "wireless microphone".
Nokia 6230	HOW-TO: Make a Nokia Pop port to female mini jack with volume control for the HDS-3 cable to the headset.
Nokia 6230i HDS-3 Headset	How to add a 3.5" jack to take a normal headset (in German).
Nokia HSU-3 Privacy HandSet	Skype handset: if you prefer to talk to traditional style handset rather than hearing the other person inside your head using stereo headsets or using the fiddly earbud, here is one solution.
Nokia Free Radio HeadSet	This HOWTO explains how to build a free radio head set for all mobile cellular phones with Pop-Port (in German).
Nokia HiFi Adaptor	A selfmade HiFi mono Cinch adaptor with schematics and parts list (in German).
Nokia 51xx/61xx/62xx/63xx/71xx	How to get a headset menue by attaching a fake headset, which is just a special short-circuit connector (in German).
Nokia 51xx/61xx/62xx/63xx/71xx	This guide describes how to build your own headset (in German).
Sony/Ericsson K750i	Headset - 3.5mm jack modding with pictures.
Sony/Ericsson HPM-20 (Portable Stereo Handsfree Kit)	Add 3.5mm earphone support.
USB to Nokia Safe Charger	This simple project shows you how to make a USB powered Nokia cell phone charger. The advantage is that it weighs much less than the bulky AC adaptor, and can be used wherever you have a computer or a laptop.
Mark I	Silly Phone Contraption: how to build a ring tone amplifier, using a small photocell and an LM324 op-amp chip.
Mark II	A cell phone ring detector made with a TLC3704 voltage comparator chip (a very low power CMOS version of an LM339).
V-Three Pte Ltd V3 - BTH3 Bluetooth Wireless Headset	Teardown report with disassembly pictures of a wireless headset.