[MOD] Palm Pre Touchstone for Droid Charge (first prototype working!!!!!)
Just ordered another touchstone to play with. They're $3 cheaper through verizon if you have a corporate discount
I'm gonna see about adding some neodymium magnets to this mix in order to hold the phone while its in a case. This is gonna require drilling into the original magnet (yes... even though there's 4 magnet contact points, theres just one big honking magnet in the touchstone which acts as both magnet and ferrite core for the induction coil. There's some pretty cool engineering going on in this thing) which should be fun. It turns out that the phone will charge through a really thin case (like a gel case or a cheap amazon two piece case) but just not through the stock verizon or thicker case.
Well... it works!!!! There wasn't any strange hitches with the setup. The wireless charge ports on the back do as they're supposed to, and the pre induction pickup works through the droid charge case. The hardest part was finding the right material for the contact points (I'll post an update later with more details about how I did this... ). The only drawbacks to this mod are that your charge is now about 1mm thicker on the back and the induction charging does NOT work through a case (at least the stock verizon case with kickstand). That being said, this mod is completely reversible (unlike every other pre induction charger to X phone mod) so you don't lose your warranty (or even your back cover).
1x Palm Pre Touchstone Charging Dock, cable and power adapter
1x Palm Pre Touchstone Back Cover
a soldering iron and solder
Total cost of materials comes out to ~$15
(0) If you don't know your way around a soldering iron or multimeter then I highly suggest you stop here and get some help doing this. The likelihood of damage to your phone is low, but doing something stupid like flipping the polarities or shorting your charge wires WILL probably fry something, either the pre induction charger, your phone, or both. I am most definitely not responsible for any mishaps or stupidity on your part. You have been warned!
1) Separate the induction coil, circult, and metal circles from the back of the Palm Pre. You're gonna have to do some digging with a screwdriver as they're stuck on pretty tight, but once you start peeling it comes off pretty easy.
2) make contacts for the Charge in order to reach the "wireless charging" port on the back. This is the hardest step by far. I ended up using some long 8mil circuit board headers that I bent, cut, and trimmed to size (see pictures for how I did the bending). I'm not sure if I recommend doing it my way as this still isn't an ideal setup, but it works. The important thing to remember is that there's about 1mm or less of clearance between the phone-side contacts and the case, so plan accordingly. Again, look at my pictures for a basic idea of how to make the contacts work, but remember that what I did IS NOT IDEAL.
3) place the contacts carefully on the phone in the correct position. Its easier to line them up on the phone than it is to guesstimate their position on the case.
4) put a small piece of tape on the back of the pre induction charger (see picture for tape location, it should be on the non-sticky side) and lay this CAREFULLY and STICKY SIDE UP onto the position you want on the back of the phone. Make sure you have not moved your contacts when you laid this down. At this point you don't need to press anything down yet, so just gently placing it is fine as long as its in the right position.
5) gently and without moving anything snap the cover back on. Press tightly, then carefully remove the cover. Everything you just placed (especially the contacts) should still be in the same place. If not, you're gonna have to start over at least with the contacts.
6) Press everything down tight, and permanently secure the contacts to the back of the cover (or in my case, the back of the pre induction charger sticky piece). a dab of superglue should be plenty.
7) solder the wires from the induction charger circuit to the contacts. Positive at toward the top of the phone, ground is toward the bottom of the phone. On the induction charger if you flip it like I did then positive is toward the top and ground is toward the bottom as well.
8) TEST TEST TEST
. Get a volt meter and make sure you're getting ~5.5v from your contacts when you put the back cover on the touchstone. If not, then you did something wrong. My mistake the first time was not putting all the sticky layers back together in the correct order. It goes black sticky layer, silver sticky layer, then coil. The coil should be sitting directly on the plastic of the cover. The order is important! Also, make sure that your polarities are correct (positive top, gnd bottom).
9) Snap everything back together and put the phone on the touchstone. It should register immediately as wireless charging. Voila la! Wireless charging for $15 on the Droid Charge! Now go get a beer and take a nap :P
Now I need some sleep... Ask any questions you want and I'll try to be helpful, and maybe tomorrow I'll put up a proper tutorial with pictures on how to do this. Till then... take a gander at the pictures of the final product
Dunno why I haven't seen this on the droid charge forums yet, but I've just bought the parts for a palm pre induction charger grafted onto a droid charge. The way I see it, the charge (and the thunderbolt) are perfect phones for this as verizon has kindly provided us with inductive charger contact points already
But wait you ask... why am I going through all this trouble when there's already an induction charger available for the Droid Charge? Simple. I really didn't want to pay over $50 for an induction charger, so $15 for a touchstone + pre backplate seemed like a good compromise. My only concern at this point is the rather limited spacing between the back cover and the battery. I'm gonna have to do some testing to see if I can actually wedge the charger in there (probably not... seeing as how verizon had to make a slightly thicker back for their charger) or if I'm gonna have to do some fancy cutting to the stock back. Stay tuned...