Samsung Galaxy S2 (i777) touchstone mod

[pm]

One of my co-workers had a Palm Pre and bought the touchstone and then he replaced his Palm Pre with a Samsung Galaxy S2 and was talking about how much he missed the touchstone charging ability - plus he had 3 touchstones lying around including one in his car.

So a touchstone is a wireless inductive charging gizmo for Palm devices (and the touchpad)

So we got to talking about how to adapt a touchstone to work on an SGS2 and the more we looked at it, the more possible it seemed. So we thought initially that we were geniuses for thinking of this... and then we did a Google search and discovered that lots of people have done this.

But... according to Google at least, no one has done with an i777. Until today. It took about two hours - most of which was spent trying to figure out how to route a ~20 gauge wire around the inside of a Samsung Galaxy S2... You might be surprised to learn doesn't have a lot of empty space inside of it to route random wires around.

I can post up detailed instructions if anyone wants to do it. But truth told, I'm not sure that I'd recommend it. It was annoying. The solder connection is microscopic, there's no room to route the wires, and getting the phone apart and back together without it looking like I'd taken it apart was annoying. But the end solution is slick and looks professional (you can't really tell that I did anything) and it is neat to charge it without wires. And it was cheap (total cost was $12 for everything. Touchstone kit is $9 here at Amazon). I'll do my wife's Nokia next. For $8, it's a good deal.

In the photo at the bottom, on the right you can see the inductive charger that I pulled from the kit and then just let the adhesive attach it. On the left, on the phone, you can see two tiny strips of copper next to the SIM card and those are the contacts that tie into the USB port of the phone. One strip goes to ground (the easy one) and the other ties to the VCC port of the micro USB connector at the bottom of the phone. If anyone wants to do this themselves, I can take the phone apart again and take photos of the wire route... it took me a couple of tries to figure out how to route it so that the phone would go back together ok.

 

[poofyhairguy]

Absolutely awesome. I would have never thought of this!

Also I love the random stuff in the picture.

 

[pm]

Absolutely awesome. I would have never thought of this!

Also I love the random stuff in the picture.

Actually, I used everything that's in that photo. Seriously. Including the microscope. Maybe I didn't use the massive set of wire cutters in the foreground and maybe I didn't need the curved needlenose pliers but the rest of it, all of it, I used.

And yeah, as far as never thought it of it. I never would have either. It was one of those engineers-hanging-around sort of things where we sort of came up with it... only to discover that lots of other people have too. Google can sometimes be a bit ego-deflating.

 

[ponyo]

Nice work! Yeah I read about people doing the mod for the Galaxy Nexus but it looked too complicated for me. Your install looks real clean. If I had the skill I would do the mod.

 

[Pliablemoose]

very cool, pm.

 

[Ksyder]

I'm not really clear on the touchstone thing but its interesting that you have a micro sim and it is not a problem.

 

[Jodell88]

I use a Palm pre 2. Does it go into exhibition mode automatically also?

Still pretty cool.

 

[soccerballtux]

Actually, I used everything that's in that photo. Seriously. Including the microscope. Maybe I didn't use the massive set of wire cutters in the foreground and maybe I didn't need the curved needlenose pliers but the rest of it, all of it, I used.

And yeah, as far as never thought it of it. I never would have either. It was one of those engineers-hanging-around sort of things where we sort of came up with it... only to discover that lots of other people have too. Google can sometimes be a bit ego-deflating.

why don't we see this feature in more phones?

 

[pm]

I'm not really clear on the touchstone thing but its interesting that you have a micro sim and it is not a problem.

Yeah, the micro sim. I used to have a plastic adapter thing but then I figured out that if you just line up the micro sim contacts correctly, then friction will hold it in place and it works and it's a bit less finicky than trying to get the plastic tray thing in there.

As far as the touchstone, basically it's a little stand that charges the phone without wires. So you just put the phone down and it starts charging. There's magnets that hold the phone down in the correct spot and then it charges the battery through the back of the phone using inductive charging.

It's a bit of a gimmick but I wanted a stand for my phone by the side of my bed so I wouldn't be trying to find the end of the micro USB cable in the dark without turning on the light and waking up my wife. A real SGS2 stand is like $30, and I thought that the touchstone was cheaper and cooler. (and we'll just ignore the ~90 somewhat stressful minutes while I took apart a ~$350 phone and hoped that it would work when I got it back together).

I use a Palm pre 2. Does it go into exhibition mode automatically also?

Yes, I think I can make it do that. If you put a resistor between pins 4 and 5 of the micro USB, you can get it to go into "dock" mode which I think is the same thing. There's a thread on it here: http://forum.xda-developers.com/showthread.php?t=820275

why don't we see this feature in more phones?

I have no idea. It's a handy thing. I guess there's Powermat but the solutions from Powermat seem sort of bulky. I wish more companies integrated it like Palm did.

 

[shabby]

You used the original battery cover or one of the thicker extended battery covers? More pics of the routing would be nice

 

[pm]

Yeah, it's the original battery cover. It fits just fine.

As far as routing, I'm willing to take apart the phone and take photos but only if someone says "pm, I am really seriously thinking about doing this" because taking apart the bezel and all that is a hassle and takes time and I don't want to do it unless someone is really serious about it.

From a high level perspective, I soldered to the resistor next to the VCC pin (which is the one on the left, the one with the triangle on it) because the pin on the USB connector was too small and scary (it was like half the width of my soldering iron tip), and then routed right (phone facing down, from the back), under the speaker, then went up the right side of the phone under the PCB, then near the top of the battery, I went left and tucked it under the SIM tray plastic and then came out under the SIM and soldered to the copper tape (buy it at Michaels or Hobby Lobby... it's a couple of bucks). For ground, pretty much anything will work, but I chose the screw to the lower right of the SIM tray and then just stuck copper tape over the screw. There looks like there's a better way to route up the left-hand side of the phone next to the antenna but I wasn't comfortable sticking a wire next to the antenna and there was a lot less room there than it seemed.

 

[shabby]

Ya don't bother then if its too much work, new phones are coming out soon so i'll probably switch so not much point doing this.

 

[pm]

Full detailed instructions - as requested by a couple of users via private messages. Sorry for the delay - I was travelling last week.

First you need to get a Palm Pre inductive charging kit. Go to Amazon and search for a Palm Pre inductive charging kit. They run less than $10 including shipping (yeah, seriously, I couldn't believe it either). I paid $8.35 for mine. While you are there, get a Palm Pre AC adapter... the kit is finicky about the AC adapter and most of mine didn't work with it. So that's another $3.70 (inc. shipping), so you are now up to $12 or so.

Once you get it, it should look like this:

And inside it looks like this:

Open the kit box, and you will see a touchstone that you stick on your desk that is the charger and then the Palm Pre case back cover with the inductive coil on it. Peel off the inductive coil very very carefully as well as the four silver circular magnets and try to leave everything intact. Set it aside because when you put it on you want the contacts to line up.

Now comes the fun part, taking apart the phone, soldering the wire, and then routing the wire.

To take apart the phone, your best bet is to watch a Youtube video (that's how I did it), but fundamentally, unscrew the 7 small silver screws and then carefully, use your fingernails (best) to work your way around the gap in the edge of the plastic. Or - if like me you don't really have much in the way of fingernails - use a guitar pick or a thin credit card... like a store shopper reward card. Slide it into the gap and work your way around... not too hard. Don't use anything metal or it will scuff the plastic. Just start in a corner and work your way around, be patient and don't try to take them apart until you've worked all the way around. And if this description doesn't make sense, then watch a i777 disassembly video on YouTube.

Once you are done, you need to solder a wire to a resistor at the bottom. There's a close up here:

You could try to solder to the VCC pin on the USB connector but it's tiny and I personally thought the resistor was much easier to solder to without risking shorting any pins. I suck at soldering so if I can do it, others can too. Just get a fine tip for your soldering iron, get it hot (but not red hot), put some solder on the wire, and then touch the iron to the wire and then the resistor quickly. Do it quickly to make sure you don't damage the resistor or the PCB. It took me three tries but I got it.

Then route the wire.

You can see the wire route. I routed right... if you are looking at it yourself, you might think the the left side looks better, but it's next to the antenna and I thought the right side was less risky. I routed down, across the speaker (the bare black gap at the bottom is where the speaker is), under the PCB, then crossed up, and then dodged the screw slot in the upper right of the battery compartment by tucking the wire under the plastic there. But you don't have to do it like this... do it any way you want (although I'd steer clear of the antenna), you just want to route from the VCC resistor at the botton up to wherever you want to put the contact.

For the ground connection, any of the screws, or the sim slot metal or anything else works. I used copper tape and just routed with the tape to the screw in above the upper right of the battery compartment. But it doesn't matter. The metal of the SIM card slot works too... whatever you want. Ground is easy.

When you are done, it should look like this (more or less):

I used copper tape ($5 from a hobby store, look in the jewelry section) for the contacts, then lined them up with the contacts from the Palm Pre coil by putting the stock cover with the coil onto the separated plastic from the phone and lining them up by looking at them together.

Yes, this mod is not easy, and it voids warranties, but it is magic every time you stick your phone on a touchstone and it just starts charging. I bought a touchstone for my car, and then one for my nightstand. For <$20, I have a car charger and a home charger and it's super easy to just put the phone near the touchstone and let the built-in magnets hook it up.

Things to be careful of:
Do not short anything. Make sure not to short VCC to ground on the USB connector
Do not flip the power connections. Make sure not to tie VCC on the inductor coil to ground in the phone and visa versa.
Don't damage the resistor when you solder to it. Be fast. But get a good connection too

I used a multimeter to check for shorts and to make sure that I got VCC -> VCC, GND -> GND.

 

[lonelyDonut]

Hey pm,

I did this mod with my friend (an EE) for my phone yesterday night.

Everything's fine, except for one thing: the back cover doesn't fit due to the thickness of the chip near the coil. So essentially, the back cover bulges, and it bulges enough that it doesn't fully close.
What's bugging me is that I positioned my "receiver" coil just like your did in the photos. And I even cut off the protective plastic from above the chip and substituted that with some thin tape to make it thinner - still bulges too much.
As a temporary measure, I superglued the back cover to the phone.

How does yours fit just fine? Did you do anything to make it fit? Please reply.

Thanks.

 

[pm]

Mine mostly fits, lonely. I say "mostly" because sometimes, I will have the phone in my pocket and I'll pull it out and one of the tabs in the corner will be popped out. But I'm staring at my phone right now, and while there is a definite buldge right on the "Galaxy S2" emblem on the back, the cover is totally on.

I didn't do any tricks to make anything thinner. I understand what you are saying when you talk about removing plastic and using tape on the chip - but I didn't do that. I still have the black plastic over everything.

You could move the coil somewhere else... if you moved it lower down, then it would likely solve the problem because the bottom is anchored.

You could take a piece of double-sided permanent tape or this (just don't get double-sided removable tape, it won't hold well enough) and put it down on the inside where the cover is coming off. It might make it harder to get the cover off, but it would solve the problem.

Or you could use a case - which would make the popping of the back cover irrelevant. It will affect the efficiency of the energy transfer of the coils though which would likely mean that the back will get warmer and the phone won't charge as quickly.

Sorry you are having problems though.

 

[gorcorps]

I kind of want to try and integrate this into a case. I saw one of those powermat things at target yesterday on clearance. It was one that came with the "power cube" which is a bunch of little dongles that plug into standard ports, including a micro usb one. I'm content not needing magnets and it just lying on a pad, plus I think it'll help keep it thin.

 

[systix]

Has anyone tried pasting the coils and circuitry OUTSIDE the backcover (covering it with just enuf tape, and just run couple of copper tape strips back inside to where the leads can be safely exposed.

This way the exterior could be covered up nicely without the cover having to pop open loose

Any thoughts?

 

[pm]

Has anyone tried pasting the coils and circuitry OUTSIDE the backcover (covering it with just enuf tape, and just run couple of copper tape strips back inside to where the leads can be safely exposed.

This way the exterior could be covered up nicely without the cover having to pop open loose

Any thoughts?

I never tried that. The guys at work who did the mod with me all put it on the inside but we did talk about doing the outside. It should work though. I think you'd swap the problem with the cover coming off for a new one with the coil coming off though...