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How to mod HTC EVO 3D for use with Palm Touchstone wireless charger

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Following up on last summer's mod to wirelessly charge the HTC EVO 4G with the Palm Touchstone charging dock (tutorial here), G&E reader drinkwd40 has come up with a similar hack for the EVO 3D.

The Touchstone is less than $15 on Amazon, which makes it one of the cheapest wireless charging solutions around, and drinkwd40 says it's much better than similar products like the Powermat. Why? Because the Touchstone "has powerful magnets in its base that connects to steel discs on the receiver, while holding the phone in place if you mount it upright in your car (even over bumps)."

Interested in wirelessly charging your EVO 3D? Find out how to do it below.

What You Need

Items

Tools

  • Soldering kit
  • Dremel
  • Multitool (pliers, knife, scissors)
  • Tape
  • Black Epoxy
  • Marker

What You Do

Evo-3d-touchstone (4) Evo-3d-touchstone (5) Evo-3d-touchstone (6)

1. Cut off the microUSB connector leaving only the +/- pins:  (a) cut clean off (b) use the Dremel with cutting disc to cut through the metal shell but leave the 5 pins uncut.

2. Use pliers to remove the middle 3 pins, leaving the outer 2 (shown in "c" above).

3. Solder each of the 2 remaining pins to a separate ~26g wire. Mix your Epoxy and apply it to the soldered area. These pins will slide so be careful not to dislodge them. This is why it must be epoxy’d first; it's difficult to put the pins back if you dislodge them). It can be easy to confuse the gold pins (what you want to solder) with the silver clips on the bottom of the microUSB assembly (these carry no current), so work carefully.

Exactly how much of the microUSB you cut off is up to you.  I recommend making the metal flush with the outside of the EVO 3D so that the epoxy will be about 1.5mm out of the phone (easier to grab).

Evo-3d-touchstone (7)

4. Remove the Touchstone receiver from the Palm Pre battery door. It's just a sticker overlaying a coil/chip, 4 steel discs, and a metal sticker. You can destroy the black sticker if you want, but you will need the other parts; don't underestimate the metal sticker.

Evo-3d-touchstone (3)

5. Put the metal sticker on the inside of the EVO 3D back door in the same orientation as it was in the Pre. It will be lower on the 3D (not in the middle like on the Pre).

6. Trim the wires to the appropriate length. Solder the +/- contacts to the wire in step 1. Note: On my EVO 4G, I was a novice solderer and melted the plastic of the door a bit. So if this is your first time, you might want to solder it before you put it in the EVO 3D. 

7. Ensure alignment works with the back cover and the Touchstone base. Plug it in et voila!

Evo-3d-touchstone (2)

8. Now just clean things up a bit by arranging the wires out of the way to minimize bulk under the cover. Tape it in place. Close the battery door and ensure a good fit.  If the cover does not fit back on the phone, grab a blow dryer and heat the door so that the plastic will stretch a bit.

I taped the door tightly closed and then heated it, which worked pretty well. I also had to widen the plastic hole for the microUSB in the battery door by about 1mm (just bent with pliers).

Evo-3d-touchstone (8) Evo-3d-touchstone (9)

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Thanks, drinkwd40!

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Jenn K. Lee

Jenn K. Lee is the founder of Pocketables. She loves gadgets the way most women love shoes and purses. The pieces in her tech wardrobe that go with everything are currently the Samsung Galaxy Note II, Sony Tablet P, and Nexus 7, but there are still a couple of vintage UMPCs/MIDs in the back of her closet.

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19 thoughts on “How to mod HTC EVO 3D for use with Palm Touchstone wireless charger

  • Does this mod make you lose the ability to charge normally using the microusb port? Looks like it blocks the charging port.

    Reply
  • Does this affect the compass like it did on the original EVO?

    Reply
  • Seems like if you leave enough slack inside the phone, you can pull out the epoxied micro-usb and free up the port? If not, then losing usb, hdmi, and possibly the compass is a pretty steep price for wireless charging.

    Reply
  • Would it still charge if there was a case on the phone? Curious if the thickness would affect it.

    Reply
  • If you’re using the USB plug, you need to unplug the touchstone receiver first. The way I designed it was to not void my warranty and use this external solution. You could make it loose enough to unplug it from the outside but that would result in a lot of bulk under the door. Tinhoy’s ‘removable wart’ concept would be cool but I’d have to see a real-life example first. To me the compass is a non-issue, b/c if I’m geo-caching (not often) I can use a real 99cent compass or disconnect the back. It will charge with a case but the case would have to be where you attach the receiver (not the battery door). See my drinkwd40 youtube channel–the video with the purple-skinned Epic 4g would be the appropriate concept for a case.

    Reply
  • This is a great project! Do you notice any difference in the amount of time to charge your phone? Do you notice any loss in cell phone signal from the mod?

    It would be interesting to find a cover that was either already modded, or slightly larger to accommodate the extra parts. Possibly the large size covers for high capacity batteries.

    Reply
  • the OEM cover is being sold for $40 right now, so I’ll wait until it is around $10 to really manipulate the plastic. The charging and signal is the same as before. I have my modded Touchstone-hardwired EVO 4G I’m putting on Ebay or Amazon soon with a lot of accessories for $250 if you have any interested family etc you can email me at drinkwd40(at) hotmail.com.

    Reply
  • Nobody mentions any concerns over the magnets effect on the micro sd card…..?

    Reply
  • Avatar of palm detective

    memory in micro SD card is solid state (flash memory) not affected by magnets

    Reply
  • Avatar of Runeazn

    What about the GPS??
    negative effects?

    btw oem cover is 16$ on ebay.

    Reply
  • Good to know the cover is cheaper now. No effect on gps. The only drawback is having to remove the cover to transfer movies >500mb in a timely manner. I use bluetooth file transfer for the small stuff. Touchstones should be very cheap since HP is no longer making phones/tablets (androidcentral). I modded my wife’s new Evo3D and improved: the ‘wart’ on the side is gone and now flush with the cover, and the cover snaps in well on all sides after thinning the areas of the cover where the wire/coil/circuit resting underneath.

    Reply
  • I was wondering if you would be willing to make one of these cases to possibly sell me. I want to try it myself, but i really wouldn’t want to mess up my phone. Please let me know.

    Thanks

    Reply
  • possibly. my weekends are running shorter but for a strange reason I enjoy those challenges. my email drinkwd40 at hotmail.com with an offer, but keep in mind it takes hours to do this right and the cost of materials is apparently around $25. I’d recommend trying it yourself with a OEM back cover as mentioned above (can’t mess up your phone b/c the only mod is to the back cover u just bought). If you can’t do it or run into specific problems I can better help with that.

    Reply
  • Avatar of Mike

    Great tutorial! Does anyone have the same problem as me whereby the position of the device needs to be somewhat perfect or else the charging seems to be on/off. Not sure if that’s good for the battery, or if there’s tweak that can be done to improve.

    Also, is it possible to improve magnet strength so the grip with the touchstone is better?

    Reply
  • what I ended up doing to my phone that you don’t see in the pics above is similar to my Epic4g mod seen at http://youtu.be/b8zXMzgYMn8 .
    All I did was move the metal discs to the outside of the phone with superglue (carefully aligned to exactly where they were on the other side relative to the coil that now remains on the inside), then I put a vinyl skin over it. Custom cuts are at skinit.com or you can get a cheap one that you cut yourself on Ebay (‘carbon fiber silver sample’ in Ebay’s search box) for $.99. The grip is perfect and the charge is too.

    Reply
  • Clarification: the coil and wire and chip are all inside. the metal discs are outside.

    Reply
  • Avatar of Mike

    Ahh, great idea! Will try that out this weekend. Another question — does your induction charging seem half as slow as normal usb cable? Direct USB cable charge seems about 2x faster. Verified the microUSB outputs 5.5V ~1amp.

    Reply
  • I’ve read that it may be slower without shorting a few wires but I’m apparently not bright enough to figure out why or if it even applies in this case. I don’t actually notice a difference, but I haven’t done a conclusive test. When my battery is dead and I need a super quick charge, I turn the phone off and connect directly to the wall outlet and bypass the touchstone. The chinese batteries on ebay are a good bridge too.

    Reply

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