Ever since I first saw the original HTC EVO’s Palm Pre wireless charging mod, I have wanted to add the same feature to one of my own devices and reap the benefits. However, I have always been a little bit cautious about soldering anything onto an expensive new device, and even just making any permanent hardware modification in general. But then just yesterday, I got an idea: Andreas has been using cheap generic cases in order to attach and add accessories to his Galaxy SII for a while now. What if I did the same?
I happen to have one or two of these cases, so I decided to see how the inductive charging coil fit into the case. Even with the coil, the case fit quite well, and I was then left only with the problem of getting the power to the Nexus. I didn’t really want to run anything into the actual battery compartment of the phone, but I also didn’t want to use the fragile microUSB port. Then, I realized that the Galaxy Nexus is one of the few smartphones with Pogo pins, and a plan began to take shape.
First, I got out the case and the Touchstone kit I bought from Amazon quite a while ago. I carefully removed the magnets and magnetic coil from the Pre’s back cover and aligned the magnets in the case using the Touchstone dock to get them into just the right place. Then, I placed the magnetic coil in the middle of the magnets, just as it is in the Pre.
Next, I taped down the magnets and the coil with some electrical tape, leaving the contacts exposed. I soldered two wires to these contacts, and then cut them so that they would end up right next to the Galaxy Nexus’s Pogo pin slot. I happened to have an old Nokia phone lying around, so I took the metal battery contacts out of that and soldered them to the end of the wires. I then bent the contacts to conform to the case and the side of the Nexus, and lined them up with the pins on the phone. Finally, I taped everything down on the inside of the case, leaving just the metal prongs uncovered to contact the Nexus’s pins.
There was one problem, and that is that my generic case has a cutout for the pogo pins – this means that there was nothing there to hold the pins against the Nexus. As a temporary solution for this issue, I put a bit of hot glue on the outside of the case to hold the pins in place. Ideally, I would have used some Sugru, but I didn’t have any on hand.
At this point, I tested out the phone and case combo on the Touchstone, and to my surprise everything seemed to work. The Nexus actually started charging, and nothing exploded. Unfortunately, I soon found out that there was a fatal flaw in my plan to use the pogo pins for power: the generic case is actually quite flexible, so it doesn’t keep pressure on the pins and contacts, resulting in what is at best a flaky connection and an unreliable charger.
Clearly, this little experiment didn’t quite work out how I would have liked, which is why I didn’t take the time to make it into a full tutorial. However, I think that the concept is still a good one, and that with the right case and pogo pin contacts it would be possible to make a wireless charging solution for the Galaxy Nexus without modifying anything at all on the phone, and just using a case. I will be modifying my design just as soon as the hard case I ordered comes in, and if everything works properly, I will post a quick tutorial for others interested in an easy and low risk solution for wireless charging. To see more details on the failed build, just have a look at the gallery below.