yashsingh1/xdaforums huggingface dataset:
[Nexus 7 Accessories] Flowyk:
can u still charge through usb? (physically) ... I want the dock but dont want to burn the usb charging ... which pinout u use?
[Nexus 7 Accessories] herbert1:
Yes, it still charges through usb and I've made my dock using the informations found here (but I haven't connected the audio pins) ;)
[Nexus 7 Accessories] Flowyk:
can u specify the pinout you projected for +5V and GND? is the GND the top one? ... I think most ppl there do it by informations there but also many burned the device
[Nexus 7 Accessories] bsoplinger:
Its been described at least 3 times in this thread and I can remember at least 2 pictures posted also. Would it have been so hard to look through the thread before asking?
[Nexus 7 Accessories] xj220gt:
I have read this thread and realized that some pics of the dock internals might be appreciated.

I am wanting to build a custom dock also, but don't want to risk frying anything.

So I decided to buy the dock and post pics. Hopefully someone knows about the internals....

All the pictures I have are higher quality, but xda mobile won't let me attach them for some reason...
[Nexus 7 Accessories] Flowyk:
If u think that the top Gnd is ok then what is the difference that breaks some devices and some don't

---------- Post added at 12:57 AM ---------- Previous post was at 12:30 AM ----------

Nice! thanks ... it answer some qs like why is the device so expensive and why some devices fryed ... can u please make schema of that with component values? Or even better will be the real values at pins
[Nexus 7 Accessories] xj220gt:
I left my volt meter at work.... So I'll have to find out tomorrow. As far as components, I'll try to figure those out some time later. I put the dock back together just to make sure it was still working hahaha.
[Nexus 7 Accessories] Flowyk:
Upload the hiRes pics pls
[Nexus 7 Accessories] xj220gt:
Output at pins is 5.21dcv. I'll work on uploading higher resolution pics. Keeps failing on xda app.
[Nexus 7 Accessories] katraska:
Thanks for publishing the photos. I can't see the circuit details, but obviously, the dock is not as simple as connect a 5Volt DC power supply to the pogo pins.

It should be very useful to have a high resolution photos, since I can't see the components and tracks clearly

The most important is the PCB with the pogo pins, and the PCB area close to the USB connector (under the ferrite high freq filter). The electrolitic capacitors seems to be a filter for audio connections

This is my "burner" dock station. As you can see, the positive is in the bottom pin. No error posibility at connect:
[Nexus 7 Accessories] herbert1:
As bsoplinger said we all use the some informations, same for katraska and me... here a post from 808HD2 with pics http://cleanimport.xda/index.php?posts/33028898/...

katraska problems are perhaps related with the experiments made using both the dock and the usb otg ?
[Nexus 7 Accessories] theBeachBoy:
there are 6 wires going to the board that connects the 4 pogo pins, anyone knows why there would be two more wires than pogo pins?

Looks like the orange/green/blue are for audio and the red/black for power.. the other big black, no idea.
[Nexus 7 Accessories] bigbop:
Probably the shield for the audio lines
[Nexus 7 Accessories] katraska:
I didn't connect OTG while I was using the dock until I realized that the tablet was broken.
[Nexus 7 Accessories] herbert1:
Not so fun, then !!!

No problem for me till now... says the man who is falling from the skyscraper. I knock on wood and cross my fingers.;)
[Nexus 7 Accessories] katraska:
Sorry, my english is not enough to understand your comment :( ;)
[Nexus 7 Accessories] xj220gt:
As promised, I uploaded some higher resolution pictures onto my picasa account.

https://plus.google.com/photos/113595422488202337870/albums/5836500183895121153

I also tried to make a sketch of all the traces and components, but forgot it at work.....

Wires from left to right on big board (not pogo board): SHGND - GND - VCC - ??? - AGND - CN2

Im thinking green and orange are the audio L+R cables and blue is ground specifically for the audio?

Sorry about the blurry pics, Was having a hard time holding the object in a good viewing angle and taking a pic at the same time.
[Nexus 7 Accessories] dirtyfnd:
Within the next few days I plan on wiring my nexus dock into my car. Since the regular charger runs at 5.0 volts 2A, is it safe to say I can supply the dock at exactly that and the unit will function without issue? I just want to get confirmation for self assurance.

Thanks.
[Nexus 7 Accessories] pwnwolf117:
is there any chance you have a digital multimeter to double check the voltage and current on the pins? i havent been able to find any posts where someone had an official dock and double checked these values on the pogo pins. im 99.99% sure it is 5v on the positive pin, but im not sure it the output current is a full 2 amps or if the current is lowered at some point inside the dock
[Nexus 7 Accessories] penguinlogik:
Yes, I used a standard 1a usb charger to dock my nexus 7 fine. Just make sure you get the pinout correct.

---------- Post added at 11:52 AM ---------- Previous post was at 11:50 AM ----------

It would be easier to check the current of the usb transformer (which is still 5v). Also, the current wouldn't be limited inside the dock. but by the device itself.
[Nexus 7 Accessories] Flowyk:
it looks like the usb shield is important component (big cable ... and connected on both sides of pcb) ... why
[Nexus 7 Accessories] pwnwolf117:
thats what i was thinking, but i wanted to hear someone else say it to confirm my thought. im thinking about modding my nexus to add a 2nd micro-usb port next to the pogo pins to charge while using OTG. before i mod it im going to test charging it with a usb cable that ill cut up and match to the pos and negative contacts. wish me luck! :laugh:
[Nexus 7 Accessories] penguinlogik:
Much easier to open the case up and use the contacts inside of there then. (Between the board and the case)
[Nexus 7 Accessories] Flowyk:
thats not a good idea ... its really hard to make microusb stabille even on new pcb ... and contact that micropins is even harder (dont short 2 3 4 ... it will be problem when charging through pc)
[Nexus 7 Accessories] xj220gt:
I was getting 5.21 dcv with nexus 7stock charger. Was getting 5.04 with a 5v. I think it depends on what you plug in.
[Nexus 7 Accessories] penguinlogik:
The 5.21v would be better as that provides a larger buffer for the voltage to drop down on load. Check the 5.04v one while its under load.
[Nexus 7 Accessories] Flowyk:
pls make photos of the small pcb with pogo pins without the holder (the small triangle) u had it unscrewed
[Nexus 7 Accessories] xj220gt:
It's soldered on :( I would rather not take that Apart.... My solder skills are not very good. Sorry...
[Nexus 7 Accessories] theBeachBoy:
From looking at the other end (pogo side), Blue looks like audio ground and orange/green are left&right (going to the pins).
[Nexus 7 Accessories] katraska:
My Nexus is working again. It has been repaired under warranty. Supposedly, they have replaced the main board
[Nexus 7 Accessories] the3dman:
Thanks to all the useful info on here, my custom audio dock is almost complete, it just needs some trim work and painting.

Here are some pics:

Before the back and top was on the audio compartment.

Again, thank you to everyone for all the great info.
[Nexus 7 Accessories] katraska:
Nice design, more considering the poor audio level in the nexus. Do you charge the device via POGO pins?

This is mine, although without power supply at the moment:

The dock is fixed exclusively with magnets:
[Nexus 7 Accessories] theBeachBoy:
Did you only connect power, ground and L/R audio to the pogo or you have some ground for audio (like the nexus dock) and other boards??
[Nexus 7 Accessories] Snoshrk:
@katraska

Where did you get that mount?

thanks
[Nexus 7 Accessories] katraska:
I have made it with fiberglass, carbon fiber and epoxy resin.
[Nexus 7 Accessories] the3dman:
Yes, power, left and right audio and ground is what I have from the pogo pins, the ground for the left and right audio is connected to the USB ground. My speakers are USB powered, so I only need one USB plug coming out and I split it to power/charge the n7 and the speakers.
[Nexus 7 Accessories] Flowyk:
Usb ground is connected to pogo ground
[Nexus 7 Accessories] the3dman:
Correct. I just didn't run my audio ground back to the pogo pins, it was shorter just to solder a splice in another spot.
[Nexus 7 Accessories] Flowyk:
In official dock is gnd somehow separated to not interfere between audio and charger ... u have it in one line
[Nexus 7 Accessories] the3dman:
Not sure, I am using the usb ground with no interference issues even while charging, I have not really looked at the official dock.

*edit* I just looked at the circuit on the official dock, and it appears that they are using one ground, they just ran everything to the circuitry before going out to the pins with it. It does not appear that they split it for interference reasons, it just looks like they did that for practical reasons. They basically did what I did above, except they ran everything to the audio circuit first then split out to the pins which in retrospect I could have done the same thing and saved myself some splices and soldering :).

I attached a quick picture of my circuit.

Painted Pics (Sitting on my 1939 Zenith Radio :) ):
[Nexus 7 Accessories] bsoplinger:
Looks nice. Did you post a schematic of the circuit you used for the amplifier & speakers?
[Nexus 7 Accessories] the3dman:
I just took apart and used an old set of USB powered computer speakers. I was to lazy to solder up my own amp. There is a picture of the guts on page 29 here. I just had to choose speakers that are not too powerful so I don't overload my USB charge adaptor plug which mine can handle 1.2A max for both charging and audio together.
[Nexus 7 Accessories] kcchen:
The mods in this thread are terrific!

Any point me to a source for the POGO pins? Interested in making a bedside stand...
[Nexus 7 Accessories] the3dman:
These are what I used:

http://www.alliedelec.com/search/productdetail.aspx?SKU=70009131

Total Cost for 8 pins: $17.50 (this includes the $5 fee + tax and ups ground shipping) Beware this site does not give you a total cost until they ship that is why I included my price so you are not surprised when they charge your card $30 and fail to tell you that is is just a temp charge to make sure your card is valid. Shipping was very fast though!
[Nexus 7 Accessories] kcchen:
Thanks! Just put an order in...
[Nexus 7 Accessories] katraska:
I used this:

http://www.ebay.com/itm/10-x-Round-...433?pt=LH_DefaultDomain_0&hash=item4ac0e30569

.. and the procedure:

http://www.bmwfaq.com/f151/soporte-para-nexus-7-a-709278/index3.html#post12393702
[Nexus 7 Accessories] Jakofff:
I recently did a mod to my car with a nexus 7, I'm checking as making the circuit to connect the pins to the power and audio ...

^^

youtube.com/watch?v=SN2npiQTDoI
[Nexus 7 Accessories] xj220gt:
Nice job! What did you use for the sliding mechanism?
[Nexus 7 Accessories] katraska:
:good::good::good:
[Nexus 7 Accessories] Prostheta:
Hi everyone - this is my first post in this area of XDA since I enboughtenified my Nexus 7 a couple of weeks ago. I'm been a hardcore Galaxy S-II user for some time and wrote the reference tutorial on replacing the screen for XDA (pinned in the i9100 accessories forum). I'm hoping to break out a few novelties for the Nexus 7 over the coming months, starting with an adventure into making a dock....hence my protracted segue into this thread....

Excellent post and photoset Ubaldo, thank you.

I am curious however, as to what the additional circuitry in the official dock actually does. It appears that the audio connector section has two matching sets of components, two resistors (both SMD 1,0k and 2,2k) and two capacitors (one SMD, one polarised electrolytic) which in the absence of any power from the USB socket part of the L-shaped circuit board infers a passive filter (I'll try and figure out a trace for the pogo board end of the audio section later). The electrolytics are more than likely to decouple the signal from any DC components or form a passive high pass filter to remove excess low frequencies. The other component are likely the opposite - a low pass filter - to dump excess high frequencies.

I received a bunch of pogo pins this week and threw together a hand-drilled board for four of them and successfully got the N7 charging via pins 1+4, although not before I had to flash a different kernel (Franco r42). Post flash I instantly got a prompt asking how to deal with being plugged into a dock. Bit of a silly question really since what else would you want to do when plugged into a dock?

So cool so far. N7 registering the presence of a charger without any magic involved. I hooked up a 1/4" stereo jack and then patched this into pins 1-3 (I presume that the pinout would be "1-4, top-bottom in portrait mode"?) and had no response from PowerAMP which was already playing through the N7's speakers. No change in the audio and nothing through the amp.

Does the additional circuitry in the official dock have any bearing on the N7 recognising that it is docked? Is there a magnet located in the dock which trips the magnetic sensor nearby? I would presume not since several people have successfully made audio docks and I haven't (yet) seen mention of any complications. No big deal, however it would be nice to use all four pins in my dock design whether I only require it for charging or not. I do like being a completist.

Glad to join the discussion. Apologies for the wall of text, etc.
[Nexus 7 Accessories] xj220gt:
I kinda had the same issue with my n7 when I received the dock. I had to update to a 4.2 ROM in order for it to start working at all. Then I had to go to settings under audio to tell it to play music out of the dock when it was docked.
[Nexus 7 Accessories] Prostheta:
Yeah it's funny because I just checked that and it says that I should have both a sound play when it is inserted into a dock and that it should route audio and notifications through there also. What exactly tells the N7 that it is docked though? The presence of a power source charging it through pins 1 and 4, a magnet tripping the sensor or a combination? I'll see if I can figure out the schematic for the dock circuits from Ubaldo's gallery photos.
[Nexus 7 Accessories] xj220gt:
Power on the pins trigger the dock. At least to my knowledge. I actually traced out the boards last time I had taken it apart.... But I left the drawing at work.. I'll try to clean it up tomorrow and post it up
[Nexus 7 Accessories] Prostheta:
It could well be that my confusion is stemming from a ROM or kernel incompatibility or bug. I'm currently running Liquid Smooth ROM coupled with the Franco kernel. I somewhat doubt it given that the ROM is based on the 4.2.1 AOSP codebase so should be 100% dock ready.

The photos of the boards are a little confuzzling because of the hot glue and lack of SMD cap values. Still, knowing the schematic will help figure out why that support circuitry was decided on. It looks like several components were not added on the pogo board. I wonder if these were "moved out" to the second board? I'm also wondering what the large cylindrical component is on the USB/3.5mm jack board....a voltage regulator? Is F1 a fuse, perhaps? It's all quite intriguing. Part of me thinks that these components are designed to protect the dock/tablet from faulty input or shorted audio outputs conditions. I've not much experience of the kind of support circuitry that a basic USB dock might require....I did discover however, that reversing the power pins when trying to charge the N7 produces no result other than the USB port on my motherboard deciding to stop working until I rebooted. Nice for those of us with wireless USB keyboards and mice....
[Nexus 7 Accessories] Flowyk:
it plays through dock only when charging ... if you cut charging it stops playing (through dock) ... even shorting gnd to vdc on tablet dont triggers the dock audio
[Nexus 7 Accessories] katraska:
When I put the Nexus in the dock the first time, I remember one message about audio redirect to pogo pins (or something like that). Since my dock does not have any magnet, the Nexus must change to this mode when it detects power on pogo pins.
[Nexus 7 Accessories] xj220gt:
Official Dock Board Schematics

Took me a while, but here is the best I could come up with on following the traces and listing the components on both of the pcb boards inside the dock.

MAIN PCB BOARD:

View attachment 1704741

POGO PIN BOARD:

View attachment 1704742
[Nexus 7 Accessories] Prostheta:
Awesome, many thanks! I'm still not 100% sure what the circuit is from your drawing however. I think ultimately it is unimportant since laying a +5,1v supply across pins 1 and 4 is sufficient.

The two resistors straight after the pogo pins on the audio lines are possible pull-down resistors to prevent pops on the audio line when dropping the tablet into the dock. The two electrolytics straight after those on the other board are DC decoupling caps. I'm not entirely sure how the resistor/cap combination following each are configured although I presume they are again some way of preventing overly high or low frequencies getting into the audio output jack. Probably low pass I would guess, to reduce interference.

One thing has got me wondering....F1....

That component could be - by the naming convention - a self-healing polyfuse. I am wondering this specifically because I am having issues charging my N7 via USB. It refuses to work until left alone for a while, then it pretends nothing is wrong. Leave it charging and you come back to it "dead" with no response from the charger. I'm thinking the N7 has resettable self-healing polyfuses in the USB power line. The pogo pins allow it to charge okay....
[Nexus 7 Accessories] katraska:
Remember that my N7 was broken after apply 5.1 volts between pins 1 and 4. The symptom was that it was not possible to charge via USB although it was possible to charge it across pogo pins. Supposedly ASUS replaced the mainboard.
[Nexus 7 Accessories] rtx101:
I wanted to mod my bluetooth keyboard case into a N7's dock using these pins. So please tell me which direction is correct in this photo?
[Nexus 7 Accessories] penguinlogik:
http://xdaforums.com/showpost.php?p=35361509&postcount=217

http://xdaforums.com/showpost.php?p=36971243&postcount=262

http://xdaforums.com/showpost.php?p=37268374&postcount=298

Screen up.
[Nexus 7 Accessories] theBeachBoy:
What gauge wire do you use to get to the pogo pins?

18GA, 16GA?
[Nexus 7 Accessories] penguinlogik:
18-24GA stranded will be fine unless you are going over 10ft, then I would suggest 18GA minimum. (and a 2A rated power supply)
[Nexus 7 Accessories] theBeachBoy:
Thanks! I bought the pogo pins, flat plastic board, wire and a 12V-5V 1.5A continuous converter.

Once I get all the parts I'm trying to put this thing in the car, connected to power and radio aux
[Nexus 7 Accessories] UncannyValley:
I'd like to point you to this thread on a german android forum, where someone created a more complete schematic of the original dock's circuits as well as high res pictures: http://www.android-hilfe.de/zubehoer-fuer-google-nexus-7/376729-inside-nexus7-dock.html#post5137815

as theres many components replaced with just zero resistors, it looks like asus stripped down electronics of the dock to a minimum.
[Nexus 7 Accessories] Flowyk:
Nice ... but the cable between boards ... is it really only cable?
[Nexus 7 Accessories] UncannyValley:
yes but it has 6 wires (the coloured ones on the schematic) :)
[Nexus 7 Accessories] Flowyk:
I mean the cylinder on cable in dock
[Nexus 7 Accessories] UncannyValley:
oh thats one of thoise i guess: http://en.wikipedia.org/wiki/Sheath_current_filter

i dont think its that important, probably to avoid that the charging may influence audio quality
[Nexus 7 Accessories] xj220gt:
So, I'm getting closer to finishing my dash mount setup, but still lack a safe way to implement the custom pogo pins :(

I'm considering gutting the official dock and using the insides, but that might get messy and its a waste of a perfectly good dock....

Can anyone update if their custom setup has messed up their nexus 7 in any way?
[Nexus 7 Accessories] penguinlogik:
It has not caused any damage to my tablet so far, although my friend has recently purchased a 3D printer, so I will be modelling a dock to be printed with the pins in the exact spot they need to be.
[Nexus 7 Accessories] xj220gt:
So, I'm getting closer to finishing my dash mount setup, but still lack a safe way to implement the custom pogo pins :(

I'm considering gutting the official dock and using the insides, but that might get messy and its a waste of a perfectly good dock....

Any updates from other's custom setups?
[Nexus 7 Accessories] theBeachBoy:
I found a much better way that the pogo pins, I think. I need to test on mine and get back to you, but if it works, it's about 5% of the work involved with these insanely small pins.
[Nexus 7 Accessories] xj220gt:
Awesome! Eagerly awaiting.
[Nexus 7 Accessories] UncannyValley:
I fixed the pins quite accurate this way: take a thick piece of plastic, drill accurately holes in it for the pins, solder cables to the bottom of the pins, put the pins into the holes and fix them with hot plastic glue. Just dont put glue on the contacts and on the solderings, so you can resolder if you would need to...

My dock did not break my N7, but since I dont trust the power supply without using the filtering that the original dock has, i stopped using it a while ago until i find out how to setup the filter correctly... any electronics expert? :)
[Nexus 7 Accessories] penguinlogik:
The only thing the dock has is emi filtering and a fuse on the 5v input. All of the resistors/capacitors on the audio output side are for noise filtering.
[Nexus 7 Accessories] UncannyValley:
yes i mean that emi filtering on 5V side, so what is it for if not to protect the N7?

btw the "fuse" is just a 0 Ohm resistor on the original dock, no protection at all
[Nexus 7 Accessories] penguinlogik:
To reduce any noise or ripple on the input voltage (which doesn't damage the device, just causes noise in the audio) because it's an audio quality device where you want a clean power source. That's why usb cables just plug directly into our devices but the dock requires extra filtering to get better quality audio out.
[Nexus 7 Accessories] theBeachBoy:
edited, will report back soon
[Nexus 7 Accessories] xj220gt:
Any luck with your nexus?
[Nexus 7 Accessories] Flowyk:
any progress?
[Nexus 7 Accessories] theBeachBoy:
yes, it works (!!), but I plugged it in the reverse polarity when doing my final test after soldering... my tablet is dead (I mean completely dead), hoping for a warranty replacement, wish me luck.
[Nexus 7 Accessories] Flowyk:
can u specifi the project? ... btw I did connect reverse it too but tablet is ok
[Nexus 7 Accessories] theBeachBoy:
I was through a 12V to 5V converter (my project is for the car so I had my power supply at 12V) so connecting reverse probably sent 12V reverse.

---------- Post added at 10:06 AM ---------- Previous post was at 09:58 AM ----------

This is what I have used:

http://www.digikey.com/product-detail/en/009155004301006/478-4688-1-ND/1687187

The pins align perfectly, just need to solder the 4 wires and use something to level the tablet (lift the other corner). MUCH easier than any pogo pin solution.

---------- Post added at 10:10 AM ---------- Previous post was at 10:06 AM ----------

Some pics from my cell. I was planning on taking many more but will do when/if I get a new tablet...
[Nexus 7 Accessories] bigbop:
What a great idea! I have a pile of old cell phones lying around that I can get one of these connectors from.

Thanks