N900 Wireless Charging
 

I was wondering if anyone tried to install one of these qi wireless charging receivers:

http://www.ebay.com/itm/Universal-QI...item2c83141608

There are versions for both micro usb connection and directly to the battery connection points (but not for N900 - for galaxy types)
.
looking for 2 things:
1. to be certain that it'll work with the N900
2. to make it as invisible as possible (even use soldering if needed to the battery connectors)

I would like to install it since i have qi chargers at home for my android tablet and would like to use them for this.

any insights on this would be appreciated.

Re: N900 Wireless Charging
 

I wouldn't mind wireless charging on my N900.

I remember chatting to someone a while ago about it on IRC.
I believe it could be possible to design a battery with the induction charger built around the battery. Obviously to fit charging coils around it the battery would have slightly less capacity. I have yet to find one compatible with the N900
However, if possible or available it would mean no modifications need doing to the device, which would be a must for me.

Re: N900 Wireless Charging
 

i won't mind to attach the coil (if it is only the thin part) to the back cover from the outside - something like this (but with only the coil being out):

http://renerento.wordpress.com/2012/...less-charging/

Re: N900 Wireless Charging
 

I don't know if it helps but here are some links to my old N900 Powermat mod:
http://ruedigergad.com/2011/08/04/th...-powermat-mod/
http://talk.maemo.org/showthread.php?t=72753

Re: N900 Wireless Charging
 

I can say that when installed the Palm Touchstone wireless charging is the bees-knees!
I had it on a N900 with broken USB port and while it is tricky filing down the charge control board to fit inside a Mugen cover with a double Scud battery it is worth is in the ease of use. Clunk and charge overnight, dead easy and no worry about falling onto the USB cable.
If there were a way to trick the N900 charge system to accept charge without shorting the data pins it would be possible to have everything soldered easy internally to USB pads and show charge state just as if you had a USB cable plugged in. I have never gotten an affirmative answer from our charging and USB expert Pali on if this would be possible so I assume not.
http://talk.maemo.org/showthread.php?t=56950

Wonko above is the guy who put a dip switch on his data pads to internalize charging, but I am a big lover of USB host mode and this is inconvenient as having to reboot to use Android apps in Nitdroid. I prefer we come up with a software fix like we did in HEN and later USB host mode manager, still hoping for a OSS Alien Dalvik for the N900 too to avoid unneeded reboots.

Re: N900 Wireless Charging
 

Back then I also experimented with an improved version that does not require the switch.
See post #19:
http://talk.maemo.org/showthread.php?t=72753&page=2
Essentially, this was created based on a hint by woody14619 to use an opto-isolator to short the USB data pins.
The idea of the depicted circuit is to only shorten the date pins when power is provided via the wireless charger and to allow the normal operation otherwise.
The soldering is a bit tricky and back then I think I burned the opto-isolator during one of my experiments while soldering but iirc it used to work.

Re: N900 Wireless Charging
 

Wow, $3.50 for ten TLP421 opto-isolators on ebay. Great a chance to solder on one of the last new N900s ever sold. Why not take a chance at ruining my precious when the payoff is inductive charging fully integrated into the phone.

Re: N900 Wireless Charging
 

a question - should this receiver work - i mean if i'll connect it to the usb and put the charger on a qi charger - should it charge?

Re: N900 Wireless Charging
 

I can tell you that generic QI micro-usb charger pads work fine with the N900. I have one similar to this (has mylar cable to uUSB plug) and use it inside an otterbox case (slight back cover mod w/ a dremel). I use this as a charger at work, and Samsung plate at home.

The connector does take the port up though, and getting it out is a pain. So if you're using the USB port more than once a week for data or misc, this is not for you. If you can't recall the last time you used the USB port for anything but charging, it could still save lots of wear and tear on your connector. (I generally sync and file transfer over wifi or bluetooth.)

One thing to keep in mind is that most pads/plates only supply 500mA to 1A. Some go as high as 1500mA, but that's about the limit right now. Those usually need a 2A brick, since even high-end Qi chargers are in the 70% to 80% efficiency range. (Qi requires 60% for their logo, logoed tend to be over 70%, non-logoed usually in the 40% to 60% range.)

The ones the OP linked above are not Qi logoed. I'm betting they want a full 1A plate to deliver their 650mA current, giving them a 65% efficiency, not bad actually. Put that on a 500mA plate though, and you'll only get 325mA, which may not be enough to even charge an N900. Worse, if your charge plate is crap, you can lose efficiency there too, so it could be less.

Summed up: Yes, they work, but don't skimp if you get it. Get a good high-end pad (500mA min) and plate (1500mA min). Anything less and you may wind up draining more than you charge.

Re: N900 Wireless Charging
 

This is great news then. I'll be ordering one to test - getting this to work will be huge :)

Re: N900 Wireless Charging
 

A naive question here: can a charger like that be applied directly to the battery and bypass the N900's USB charging circuit altogether, as per sixwelledbeast's post #2? I too would like to keep my phone intact but I would not mind sacrificing one of my many spare batteries for the experiment.

Re: N900 Wireless Charging
 

Speaking of huge... Mind the size of the pad. Some are wider than the N900. Consider orientation and dimensions when making your selection as well. ;)

Re: N900 Wireless Charging
 

I'm going to say "unlikely". AFAIK the battery still needs its charging current/voltage to be setup properly to do charging, and a chunk of that circuity is in the phone. Someone with more battery experience like Dr_Frost_DK may have better insight on that than me though. Even if it could direct connect to the terminals, I'm not sure it could do so in a live system, where the device is drawing at the same time.

Re: N900 Wireless Charging
 

Thanks Woody, that's exactly where I was heading with that question. I would not expect to connect the receiver's contacts directly to the battery contacts. But, assuming some magic circuit between the two, would the phone's firmware be able to cope with it? Reporting the correct charge, for example?

Re: N900 Wireless Charging
 

But Palm Touchstone only works with it's charger, right?

Re: N900 Wireless Charging
 

AFAIK the Touchstone only works with Touchstone chargers. Are you seeing another brand in the wild for public use similar to free WiFi?

I did get an email from Estel on a BME trick for enabling charging in software though it seems that it enables a dumb high draw mode which would possibly undervolt the charging system.

I would like to hear thoughts on using this from BME experts

Re: N900 Wireless Charging
 

BTW, are the two contact points of a qi receiver a D+ and D-?

Re: N900 Wireless Charging
 

Well, at least some more words of warning:
Be very sure to know what you are doing as the pins that are accessible underneath the battery do not have any protection circuits, iirc.
See also a link to a post by joergrw in the thread I linked before.
Also have a look at the USB pin-out.

In the end, you do this all on your own risk and responsibility.
There may be many subtle pitfalls that may result in sub-optimal behavior or even worse, e.g., components getting hot or the battery not being fed with the right current/voltage may even result in fire or the like.
As another example: voltage drops at components you put in the circuit may result in a too low voltage for charging etc.
So, while there are reports of working configurations, in the end, everyone does this on her/his very own and may experience widely varying results.

So, to repeat: be sure to know what you do and be aware that you do this on your own responsibility.

Re: N900 Wireless Charging
 

Yep I read all and a lot about USB today, because currently I'd have to take out my battery to charge it. So I've been finding different ways to charge the battery, from repairing the micro-usb, to creating a new usb connection and wireless charging. So far it seems like Touchstone is the safest, although it only works with it's own charger. So if that charger goes missing, I'm doomed and have to order another charger. Creating a new usb connection seems interesting enough, but I'd really like to implement wireless charging. Not sure to go with qi, or touchstone.

Re: N900 Wireless Charging
 

Akkumaru, is there a more common charger that you are finding compared to Touchstone?

Re: N900 Wireless Charging
 

The dimensions of the one i posted seems perfect :)

Re: N900 Wireless Charging
 

Looking at one of the links above it has been done.
If it is putting strain on the charging circuitry inside the device it yet to be proven.
It seems the battery charges without the device knowing about it. I would assume shorting the Data pins would trick the device into thinking it's charging.

Re: N900 Wireless Charging
 

Shorting data pins makes the N900 able to charge as normal from 5v run through the ground and USB 5v+ pads.

If you have a Li-ion charge board to add to your phone that charge logic will handle the required 4.1v charging voltage and terminating charge for a full battery on your 3.7v BL-5J battery, it takes a reboot in my experience to get the N900 to report correct charge state once you are finished charging.using an auxiliary charge manager circuit.

Re: N900 Wireless Charging
 

I'd say Qi is far more prevalent today that Touchstone. You can find Qi based items all over the place. In fact, there are apparently 3 separate charging systems out in the wild, though until to day I'd only heard of one. Guess which one is winning... Short of Apple grabbing one of the lesser specs (or inventing their own) Qi seems to have the foothold.

Most devices have Qi built in, or (if smart) have connectors under the back cover, and a slim insert or cheap back-plate with the receiver. That would allow them to simple replace that insert or back with another standard receiver if the tables get turned somehow. Right now though, that market looks to be 100% Qi based. (Samsumg, LG, Qualcomm and Nokia are all behind it... so there's a reason it's winning.)

The "best" way to do this with the N900 as is today would probably be a pass-through system. The power on the receiver would switch the external USB pins off (via relay or transistor) and connect on in a way that make it look like a charger of proper amperage. That allows the device to continue to know about charging in the way it's used to, eliminates port wear, and doesn't require a software re-write.

Doing that in form factor for the N900 would be tough. But if the Neo900 were to have that built-in with exposed pins for power-in from such a plate? May be a last minute request to throw in there?

Re: N900 Wireless Charging
 

Hola comrades, I've been requested to post whats below. I hope it helps:

Sorry mods. Couldn't help myself.
 

Glad to see Estel is taking the ban policy seriously, as always. :rolleyes:

Honestly, yes, opto's are almost always overkill, but they're a risk reduction tool. Which would you rather do if a static charge hits your device just right? Replace a 50¢ part designed to take the hit, or lose your N900? It's your device, and your decision to make based on your opinion.

You know what they say: Opinions are like Estels. Every forum has one, and they all are usually banned. :D

Re: N900 Wireless Charging
 

FWIW I have also ordered a Qi universal charger just to see, It looks to protect the USB port from dust as well as being easy to remove for host mode or mass storage. I will post in a thread, maybe not here though, my results when it arrives.

Re: N900 Wireless Charging
 

I posted the steps to get the Qi universal receiver to work with the N900 and charge properly: http://talk.maemo.org/showthread.php...01#post1431701
No mods to phone required beyond a bit of electrical tape, some soldering required as the Qi charge receiver linked at the top of the thread does not have shorted data pins required by the N900 battery charging circuit.

Re: N900 Wireless Charging
 

As I am looking for Qi chargers atm I ran into this http://katalog.we-online.de/en/pbs/W...5#vs_t1:2_ct:1

can be ordered at rs-online.com (be aware that the older rather thick coils are also available but might not fit a phone I hit the search with the first digits of the WE productcode)

Re: N900 Wireless Charging
 

My final install was to stick the charge receiver onto the back of my Mugen battery cover, with a double Scud battery there is just not enough room.
I would love to find some sort of elastic super sticky membrane to stick this to the outside of my cover as it looks rather junky with electrical tape.
I suppose it is pretty cyberpunk-now though, badass pocket computer phone, shabby post-apocalyptic exterior.
Qi is pretty cool, I really like it and how my port is now well protected at all time unless I am doing USB host mode.

Re: N900 Wireless Charging
 

is it charging with kernel power modules instead of bme? i found that this is the case for all weak chargers i used with N900 - including portable ones. this way there will be no need to mess with the pins.

Re: N900 Wireless Charging
 

I have KP installed for the last few years, I think you need to have Pali's new BME alternative and some edited files to bypass the shorted data pins, though I understand that is not without issues.

I get charging at about the same rate with a 2000mA(2amp) mains to USB charger and Qi pad as I do with my Nokia 1200mA(1.2amp) mains phone charger. Have not wired the phone adapter with an ammeter.

Re: N900 Wireless Charging
 

i use the following to change charger modules:

stop bme
modprobe bq2415x_charger

Re: N900 Wireless Charging
 

Just got my Qi Universal Charger receiver from ebay:
http://www.ebay.co.uk/itm/Qi-Univers...E:L:OU:US:3160

------
connected it to my N900 - it does not charge with bme, but after executing these it charges wirelessly just fine and the yellow charging light is on (through the micro usb connection and without doing any soldering/electronic mess):

stop bme
modprobe bq2415x_charger

A few issues i've noticed:
1. the charging works great - even through the back cover - no need to place the coil outside (the coil itself is very thin), but the part that is connected to the coil cannot be inside the cover since its a little too thick for it to close properly.

2. i am thinking about attaching the small little thick part which is connected to the coil right under the camera, make 1 or 2 little holes for the coil's wires which will reside inside the cover, and another small hole for the microusb wire to go under the cover and into the micro usb socket of the n900.

3. while charging, the N900's screen sometimes gets awakened and after its time limit goes off again - strange behavior i sure want to solve.

Re: N900 Wireless Charging
 

Does it not just need the data pins shorting?

Re: N900 Wireless Charging
 

Impeham, I tried just the coil without the black backing, when stuck under the cover against the battery. The blue in-contact pad light did not come on and the phone didn't begin charging, the contact light comes on even if the receiver is not connected. Not 100% sure what the black layer does but it does keep the coil from receiving when it blocks the charge pad and possibly prevents some sort of interference from behind. Back during my Palm Touchstone charger days there was no black barrier layer just a coil.

Re: N900 Wireless Charging
 

Mine was charging very well - both the blue light of the charger and the yellow of the N900 were working and i charged to from 70% to full this way. can't explain the screen turning on and off once in few mins though.

Re: N900 Wireless Charging
 

Are you running just KP52 or also Pali's new BME?

Re: N900 Wireless Charging
 

just kp52 - don't remember installing anything specifically related to BME. how can i verify this?

Re: N900 Wireless Charging
 

Is it possible to hook one of these up in such a way as to allow i to charge the battery while leaving the USB port free for host mode?