English

Success with Palm Touchstone wireless charging


#1

Very happy. I finally got to fix my old Palm Pre touchstone back cover circuit into the back of my Fairphone 2. Rigged up a connection to the 5 way pogo charge pin and ground and it works!

My Fairphone 2 is sitting on the touchstone as I type, charging successfully.

If you want to do the same thing, palm touchstones and back covers are available inexpensively on eBay. I’m happy because this is the second phone I’ve successfully modified to wirelessly charge with my reused touchstones (the first was my old Samsung S3).


#2

Sounds awesome.

Some internet searching suggests to me that the placement of the induction coil into the cover is vital and not trivial.

So I think everybody interested would be happy about some instructing pictures of what exactly you did.


#3

I’ll have to get a camera out of storage to take some photos.

Although the alignment is much easier than you might fear. The external touchstone has 4 magnets in it which line up with 4 small metal discs in the thin touchstone coil assembly which you stick into the back cover. I simply lined that up with the battery area. The phone magnetically sits in the right place on the touchstone, slightly to one side.

Photos will follow this weekend.


#4

Here’s some photos:

First the touchstone. I had to swap USB power supplies until I found one that worked. The Palm original one works fine. I suspect the PSU just needs to be dumb.


This is the palm pre back cover with the touchtone charging circuit. It peels off carefully.

The four round bumps are little metal discs that are magnetically attracted to magnets in the touchstone to align the two coils. The Palm Pre sat centrally on the touchstone.

Here you see the FP2 charging on the touchstone.

Charging at full rate.

And having the charging LED on, which was nicely green this morning.

Here’s the quick and dirty hack to make it work. I put the coil over the battery with two fine wires attached to the coil circuit. Under the PVC tape I have two pieces of copper foil which I soldered the wires to. I insulated 3 of the 5 pogo pins leaving just pin 2 - charge, and pin 3 - ground. Which I carefully made a layered tape connection to. I had to add 4 layers of PVC tape to hold the connections together. Later I’ll add a custom PCB, but I wanted to see if it worked before I go to all that effort.

Finally, here’s the closeup of the coil in place, stuck to the inside of the back cover. There appears to be enough room in the case for all this without forcing or squeezing, as the Palm charging coil circuitry is very thin.

The magnets hold the phone in place, but it doesn’t seem quite as strong a hold as on the palm pre. I think the back cover is a little thicker and the phone a little heavier., but it does hold. The good thing is that once you feel the magnets holding it in place it is charging. The hold is strong enough to lift the touchstone.

I’m very happy to have wireless charging again, for an outlay of $0, and less than an hour of time. Let me know if you do the same thing!

Lastly, I just have to say that without this community documenting the connectors inside the phone and giving me the confidence to try, this wouldn’t have happened either, so thank you all.


#5

This is really great news. I loved them all, my Palm Pre, the Pre+, the Pre2 and the Pre3. There was never a better phone and WebOS was awesome already 10 years ago.
Now I have a new mission for my Touchstone :smile: just have to cannibalize my working Pre+ :cry:
If anyone needs an original Palm Touchstone, just mail me. I have two spares.


#6

Your Pre+ will still work, it just won’t charge on the touchstone. Alternatively, the back cover is available on eBay for <€5 i.e. https://www.ebay.co.uk/itm/Black-Battery-Back-Cover-For-Palm-Pre-Touch-Stone-Touchstone-Original/350760556822?hash=item51aaf55916:g:hbsAAOSwWBJXA87P