An android phone may fall out of use for a variety of reasons. Maybe you just upgraded to the latest and greatest model, and held on to your old one. Maybe it stopped working properly in some way, but wasn't totally ruined so you felt bad throwing it out. Maybe like me, you're a pack rat and horde all sorts of shiny, semi-working technology . . . you know, just in case.
I'm a buy it used and avoid long term contracts kind of guy--I'm on pageplus and get my 4G from a router from Ting, which is a kludge of a way to do your phone service, but it keeps me out of expensive contracts that I have to stick with for years and years. One of the downsides, however, is a total lack of warranty. So, when my fancy Razr Maxx stopped charging about a year ago (hey, so I'm three generations behind the times, sue me), I simply had to set it aside and buy a new phone (S3, hurray!). The Razr still worked fine, I just had to drill a hole in it and extend a battery wire out so I could attach some alligator clips to those and attach that to a USB charger. Not an elegant solution, but it worked out okay until I replaced it!
So if you're lucky and your phone is just old but still working, all you'll need to do here is plug it in near the location you want the webcam. For me, I had to open the case and modify some things.
Here's where that soldering station from thediyoutlet came in. I have no reservations whatsover recommending this tool, some of you may have seen my old soldering station instructable, but this is waaaaaay better than that mess. It served me well for many years, but this is a definite upgrade. This one has a soldering iron, hot air gun, and a variable power supply, all of which I ended up using for this project.
My first thought was to try and repair the actual USB charging port. The heat gun that comes as part of the station worked great to loosen the solder on the port, allowing me to remove it. I then tried to wire the end of a USB cable directly to the circuit board. The soldering iron worked great and had a really pointy nib for use on SMD circuit boards, but my hands just aren't steady enough for that delicate of work, I guess. I made a mess of things and had to start over.
I realized there's no real need for a USB connection! I decided to make the direct battery connection permanent (and less messy). I took that same USB cable, stripped the positive and negative wires (usually red and black, but in this case gray and black--green and white are data, so you don't need those here). I decided to remove the battery completely since the phone would be permanently powered, and lighter without it. Before I attached the USB wires to the power inputs, I attached the phone to the benchtop power supply and made sure it was working fine without the battery. No problems! I screwed the wires in place, and added a dollop of solder to each for good measure.
Finally, using a dremel I carved the hole at the bottom of the phone's casing a bit deeper, to fit the fatter USB wire. Sticking it in place with hot glue, I then tested everything on a USB wall charger before using epoxy to keep the USB cable in place at the bottom of the phone, reassembled it, and was ready to go!