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Fenris_Ulf
[H]ard|Gawd
- Joined
- Nov 29, 2004
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I know this isn't the traditional computer case mod, but modern smartphones are just small, mobile computers and this is a case mod of one, so...
I really like my new Galaxy Nexus, but one of the big problems I had with my original Droid was the micro USB plug had started to wear out after a year and become unreliable. Looking for a solution, I came across a fairly impressive mod on an Evo here:
http://doesitpew.blogspot.com/2011/03/htc-evo-4g-mods-beyond-stock-and-one-of.html
I decided that when I got my Nexus I would try to add an inductive charger. Fast forward to two weeks ago and I had a shiny new Nexus in my hands. First thing was to order the extended battery and cover, a few Palm Touchstones, and a Palm Pixi touchstone cover. The Touchstones were about $8 each and the Pixi cover was $7. I like the extended cover, it feels like a more natural shape for the phone. A big resource was the teardown at Tech Republic which gave me good insight into planning this.
http://www.techrepublic.com/photos/cracking-open-the-samsung-galaxy-nexus/6334013
Based on the internals, it looked nearly impossible to tap into the USB plug - it's just too integrated and there's nothing exposed to tap into. The pogo pins looked like a much better place to tap, but there is no information that I could find about the pinout. Some "experts" claimed they had been disabled in the Verizon version due to the Verizon car dock lacking the corresponding pins. I played a bit with my multimeter and figured out that the two pins closest to the power button are ground. The third pin has about 83K ohms of resistance to ground. Attaching 5v across the pins caused the phone to indicate it was charging, so it looks like it wasn't nerfed by Verizon.
After coming up with a plan, I used a plastic spudger to open up the case as seen in the ifixit teardown:
http://www.ifixit.com/Device/Samsung_Galaxy_Nexus
I peeled the inductive charging circuitry out of the Pixi - it's all on one big sticker, and used a little spray adhesive to stick it on the inside of the extended battery cover. Here's the phone case, internals, and extended battery cover with the Pixi inductive unit installed. The two wires are from an old sacrificial USB cord will be used to connect everything. Sorry for the crappy pics, but all I had available was a six year old cheap camera.
The only decent place to connect the wires on the pogo pin connector was the top, so I carefully soldered them on. There isn't enough space to run them over the pins so one goes off to the side.
The wires were then threaded through a conviently placed hole and the main cover was re-attached.
Testing the inductive charger on the Touchstone showed that the "top" contact was the positive and the lower was the negative. Then the wires were shortened and soldered to the contacts on the Pixi cover:
All that was left was to put the battery back in, close it up, and test on the Touchstone. Here's the Nexus on the Touchstone:
And here's a front view:
You can see that it shows that it's charging both in the notification tray and the lockout screen. It seems to charge about as fast as the regular plug in charger, but I haven't done any real testing on it yet. One complaint is that the back of the Nexus is fairly slick and doesn't grab onto the surface Touchstone. There are four magnets on the Touchstone that align it, but it definitely needs more friction to keep it from sliding off when bumped.
I really like my new Galaxy Nexus, but one of the big problems I had with my original Droid was the micro USB plug had started to wear out after a year and become unreliable. Looking for a solution, I came across a fairly impressive mod on an Evo here:
http://doesitpew.blogspot.com/2011/03/htc-evo-4g-mods-beyond-stock-and-one-of.html
I decided that when I got my Nexus I would try to add an inductive charger. Fast forward to two weeks ago and I had a shiny new Nexus in my hands. First thing was to order the extended battery and cover, a few Palm Touchstones, and a Palm Pixi touchstone cover. The Touchstones were about $8 each and the Pixi cover was $7. I like the extended cover, it feels like a more natural shape for the phone. A big resource was the teardown at Tech Republic which gave me good insight into planning this.
http://www.techrepublic.com/photos/cracking-open-the-samsung-galaxy-nexus/6334013
Based on the internals, it looked nearly impossible to tap into the USB plug - it's just too integrated and there's nothing exposed to tap into. The pogo pins looked like a much better place to tap, but there is no information that I could find about the pinout. Some "experts" claimed they had been disabled in the Verizon version due to the Verizon car dock lacking the corresponding pins. I played a bit with my multimeter and figured out that the two pins closest to the power button are ground. The third pin has about 83K ohms of resistance to ground. Attaching 5v across the pins caused the phone to indicate it was charging, so it looks like it wasn't nerfed by Verizon.
After coming up with a plan, I used a plastic spudger to open up the case as seen in the ifixit teardown:
http://www.ifixit.com/Device/Samsung_Galaxy_Nexus
I peeled the inductive charging circuitry out of the Pixi - it's all on one big sticker, and used a little spray adhesive to stick it on the inside of the extended battery cover. Here's the phone case, internals, and extended battery cover with the Pixi inductive unit installed. The two wires are from an old sacrificial USB cord will be used to connect everything. Sorry for the crappy pics, but all I had available was a six year old cheap camera.
The only decent place to connect the wires on the pogo pin connector was the top, so I carefully soldered them on. There isn't enough space to run them over the pins so one goes off to the side.
The wires were then threaded through a conviently placed hole and the main cover was re-attached.
Testing the inductive charger on the Touchstone showed that the "top" contact was the positive and the lower was the negative. Then the wires were shortened and soldered to the contacts on the Pixi cover:
All that was left was to put the battery back in, close it up, and test on the Touchstone. Here's the Nexus on the Touchstone:
And here's a front view:
You can see that it shows that it's charging both in the notification tray and the lockout screen. It seems to charge about as fast as the regular plug in charger, but I haven't done any real testing on it yet. One complaint is that the back of the Nexus is fairly slick and doesn't grab onto the surface Touchstone. There are four magnets on the Touchstone that align it, but it definitely needs more friction to keep it from sliding off when bumped.
.