yashsingh1/xdaforums huggingface dataset:
[Nexus 7 Accessories] UncannyValley:
Yes, audio pin connectors seem to have the same source as the headphone plug. I connected a 3.5mm audio jack to a volume control from a broken headset to the audio out. So i can attach whatever output device i want, at first my little battery powered speaker.

First i thought it might be line level output, but its the same low voltage as the headphone output and volume is fixed by software (for whatever reason).

For the pogo pins, I got me some cheap P75 J1 from ebay. The pins have 0.74mm diameter but are quite long with 17mm.

Now i'm building up a plastic stand for the Nexus7.

Thanks to everyone who contributed informations on the pogo connector here!
[Nexus 7 Accessories] MetalMan2:
2) so it sounds like this is a pre-amp output... exactly what is needed for a car installation when using an amplifier for speakers. Hopefully the quality is good/nearly on par with the audio quality from a USB DAC.
[Nexus 7 Accessories] zapro:
The output is just line level. The sound quality is PANTS since the Realtek DAC that's bundled with the Tegra3 is, well crap. I'm using a USB DAC with modded ROM, and it sounds sweet ;)

To use the pogo pins you's just treat them as any other line out, so you'd need some kind of preamp/volume control before your amps.

// Per.
[Nexus 7 Accessories] vivanshah:
Which ROM/DAC are you using??
[Nexus 7 Accessories] zapro:
I'm using the Poitee ROM and a Audiotrak Optoplay DAC

http://www.esi-audio.com/products/optoplay/

// Per.
[Nexus 7 Accessories] CNLiberal:
I just purchased an N7 based upon the work Timur has been doing. I want to use the tablet in my SUV for music/nav but even at 32GB in the N7. that's just not enough storage. So, after looking at the faux123 kernel, I see that USB OTG is implemented, but I don't see a mention of USB OTG + Charging. At least, not in the OP. Do you know for _sure_ that it's working in faux123? I'm purchasing all the little bits I need today for my install. Exciting!!

EDIT: I found a few posts saying that USB OTG + Charging is working as expected. This page of the thread shows it.
[Nexus 7 Accessories] Dillonjs:
Asus Japan posted something about a Nexus 7 Dock being released soon. It was reported on www . phonearena . com/news/Audio-dock-for-Google-Nexus-7-coming-next-month_id37207 if you are interested in reading up on it.

Thank you all for your efforts and input here, I am using this thread to aid in my own implementation with the pogo pins as I am building a dash mounted cradle that will allow me to use the Nexus 7 instead of my headunit. I have a ton of time on my hands. :rolleyes:

Aloha!

Jeremy
[Nexus 7 Accessories] mrsatan:
Id kickstart it if it worked with cases.
[Nexus 7 Accessories] Flowyk:
it will work with case ... just remove case before mounting and add case after unmounting ...
[Nexus 7 Accessories] elegos:
Keep this discussion in topic please.
[Nexus 7 Accessories] UncannyValley:
Audio out

so, since the audio out is supposed line level, will it damage the n7 if I connect a headphone (or my headphone level speaker)? Or can I use it safely if I dont turn up the volume to full power (potentiometer ~600 Ohm)? A quick test setup didnt break anything, but maybe it can happen over time or if its too loud? :eek:

Or does the N7 have some safety for that?

As I understand, a line level output is expecting a high Ohm output device and can short circuit if a low Ohm device (headphone) is connected.

Does anyone know or can measure impedance of the N7?

Please help a noob (and others too maybe) :)

edit: with a case like this from igadgits it can work ;)
[Nexus 7 Accessories] :
Hi guys, did anyone try go hook up a TA2024 amp to the POGO plugs on the nex7? I have a beercrate with some built-in speakers and i'd like to mod a dock on top of the thing but the problem is, as you can see on this image:

that it has three wires, and the nexus has two plugs.

normally, it should hook up to a 3,5 mill jackplug like this:

can anyone give me a tip on what to do with the mantle? if i don't add it I get a really weird sound coming out of the thing :P

cheers :good:
[Nexus 7 Accessories] stranger8:
This is just a guess because I'm not familiar with a TA2024 amp. Assuming it is a stereo amp, you need to feed it 2 channels (-L, +L, -R, +R). The red and yellow wires are probably +L and +R, the black wire will be common for -L and -R. If I understand correctly, the pogo pins work in a similar way. The centre two pins are +L and +R, the GND pin is used for -L and -R.
[Nexus 7 Accessories] :
Ok, i'll try connecting the black one to the GND then as soon as i have one of these guys (dunno the translation) ill try it :) thanks!:highfive:

p.s: this is the ta2024 amp: http://www.kratradio-ta2024-versterker.nl/info/Aansluitschema TA2024.jpg
[Nexus 7 Accessories] elegos:
That seems to be a balanced TRS cable, which can be used both as balanced mono or unbalanced stereo (balanced mono: yellow and red are the same input but inverse phase, while unbalanced stereo they are the L and R channel, while the black is always ground)
[Nexus 7 Accessories] katraska:
Thanks for your excellent information.

I am working on my own nexus 7 holder for my car, with pogo pins

(i would like to post the photos or the web where i am writting how to do it, but it's not allowed for me :( )
[Nexus 7 Accessories] 808HD2:
Nice. I have a similar amp that I bought and I'm about to finish my dock.
[Nexus 7 Accessories] UncannyValley:
This amp looks like its built for use with headphone outputs, but someone stated the N7 dock connectors have line level output. Same question as for my setup above, i think, since it is not recommended to connect a low impedance device as a headphone to a line out for it may break the output device. :confused:
[Nexus 7 Accessories] :
The amp should be able to handle line in input, but it should put a limiter between to control the sound loudness :) I posted a pic of it before and it *should* work

I'm not connecting anything until I have that switch :P

The output is NOT for headphones with the amp
[Nexus 7 Accessories] :
Here's some more interesting stuff:

- managed to get the nexus to charge with the pogo pins using a 12v (7Ah) battery, a usb car charger, and a (male)usb to (male)miniusb cable. tore that cable apart and connected the red and black tips to the nexus pogo :D

- the TA2024 and the usb car charger work simultaneously on the battery when parallel connected. in series wont work :good:

Onwards to the audio! :cool:
[Nexus 7 Accessories] 808HD2:
So I got my dock pretty much hooked up and running.. its just not giving me a charge but ill look In to that..

http://static.photobucket.com/playe...cket.com/albums/b277/faded808/VIDEO0004-1.mp4

Ps. I got it to charge, I guess the xoom charger wasn't giving enough current. I tries to just hook it up with a USB and the stock charger and is was charging. So next up is a new charger :)
[Nexus 7 Accessories] :
Well i made some progress as well :good:

Here's a picture connecting the POGO pins to the USB power and TA2024

Closeup of the pins:

Closeup of the connection:

The TA2024 and car charger to usb both working on a 12v 7Ah battery:

The internals of the beercrate:

The mighty Jupiler beercrate! (belgian beer = :good:):

And this will be the lid where i'm going to work on :):

More stuffs coming :)
[Nexus 7 Accessories] dinomight:
Ok,

So i hooked up 5+ and gnd to pins 1-4, and it started charging YAY!, but now it won't charge over usb (at all) the device has completely discharged and the only way to charge is go in to bootloader mode and hook up the pins ( i used guitar strings like in this device,and now just plain wire, pressed against the pins )..... even then it charges insanely slow.

If i let it boot, it shows the "audio device" dialogue and then powers down immediately,(there is a dialogue that says this but, it doesn't just power off.) I've tried using the stock charger, another 2amp usb charger. nothing get's me a charge. after charging via pogo, in bootloader, i was able to get to 22%. i booted in to the system. It said it was charging but slowly it discharged. I tried getting in to adb but that seemed futile (my screen cracked the day before and was unresponsive.) I'm not sure why it isn't charging via usb.

Any clues?

I should also mention that i had to revert to CWRecovery (non touch) due to the unresponsive screen. I am not on 4.2.1 yet(i'm on 4.2) and i can't update since it doesn't have enough power to do so. I could really use help....

oh and one more thing. If i plug in the usb charger and it is off(nexus 7), i get the little white battery charging animation for about 5 seconds and then it disappears.

I'm about ready to send it back (cracked screen+insurance.... thank you). but i need to get my stuff off of it, and i need to revert to stock. Has anyone else seen a problem charging after they tried the pogo pins?

Currently i've got no power, and my pogo pins are at home

and one last thing.... i want to avoid this happening with my replacement.... why could this have happened.... what do i need to avoid, i may have swaped 5+and GND the first attempt.
[Nexus 7 Accessories] :
from left to right when the tablet is with the screen on the top:

GND - Audio left - Audio right - 5v
[Nexus 7 Accessories] jonnyg1097:
How come you plan on having the nexus 7 laying on it's back and not angled for landscape use? Wouldn't it be easier to have it connected to the pogo pins rather than it flat?
[Nexus 7 Accessories] :
It will be connected with the pogo pins :p, it'll automatically rotate if I'm right or ill lock the rotation. Do you have an idea otherwise on how I could set it up right? I think it'll be very hard then to find a good angle.
[Nexus 7 Accessories] Flowyk:
It will be small app or maybe the integrated dock app could do it

Dino try to connect pins right (top is gnd) ... Maybe u will be lucky
[Nexus 7 Accessories] jonnyg1097:
You're right! it does rotate that slipped my mind when I made the post.

Although, looking at my galaxy nexus now with it in the pogo pins dock it does rotate depending on which orientation you have it in. i.e when holding the phone and dock in portrait mode it will stay in portrait mode. As for ideas, I would just say set up a block of wood x distance away from the pogo pins and the tablet would be slanted to the desired angle you want it.

I was really just asking because I saw the iphone in the pic and it clicked in my head that while that's standing your tablet isn't, so I thought I'd ask about it.
[Nexus 7 Accessories] :
yeah but for the iPhone its easier eh :) it can balance itself then with the 30pin connector if glued correctly, and for the Nexus 7 it would be harder to find a correct angle and to let it stay like that. Plus the wooden plate is only 10mm thick
[Nexus 7 Accessories] UncannyValley:
do I understand right, that you connected all pins 2-4 to GND? That would mean you short circuit pins 2 and 3 (audio). maybe that's the problem for discharge
[Nexus 7 Accessories] NeoTechni:
By working with cases, he specifically meant not having to remove the case
[Nexus 7 Accessories] Flowyk:
Little OT but i cant imagine dock with pogo that works with/out case and be solid enough to buy it ... Maybe some clip but it will look weird
[Nexus 7 Accessories] r00t4rd3d:
Can someone verify some stuff for me?

With Android 4.2 I can apply GND and +5v to the right pogo pins and it will charge with no other modifications and is the pinout correct in the picture below?

I make docks and stuff.

Also did you guys see this?

http://www.cultofandroid.com/20037/im-jelly-official-asus-nexus-7-dock-gets-unboxed/
[Nexus 7 Accessories] :
Confirm
[Nexus 7 Accessories] kasemodz:
Hmm, I watched the unboxing of the finally released nexus dock! Gosh just can't wait till it gets to US, but one thing interesting I saw was that the usb charger is 5v, 2.0A. (Click on the link and watch the unboxing right around 0:50). Quote from the instruction manual in the unboxing video.. "Ensure that your power adapter provides a minimum output of 5V DC 2.0A........"

Someone previously said that the pogo pins can only supply upto 800mA. If the charger is 5V, 2.0A and its main purpose to charge via pin 1 and pin 4, then there shouldn't be any issue for "slow charge". It should charge at the same rate as the normal usb charger.
[Nexus 7 Accessories] Flowyk:
U can have loosing on way from adapter to tablet ... its easy to have slow charge when using low quality products
[Nexus 7 Accessories] penguinlogik:
Finished my mount, just need to put it in my truck and everything should be good.

[YOUTUBE]E2L7BEcsZEc[/YOUTUBE]
[Nexus 7 Accessories] penguinlogik:
From what I've seen, the pogo pins output whatever is output to the headphone jack except its stuck at max volume.
[Nexus 7 Accessories] UncannyValley:
anyone sure about this? high or low impediance? anyone can measure it or look it up somewhere?

i want to use the audio out but dont wanna break anything...
[Nexus 7 Accessories] zapro:
It's the same output that is routed to the dock pins and the Headphone jack. The Nex7 senses it's docked when the Powermanagement chip sees 5V at the dock connector, telling the OS to turn the volume up. There is a detection switch in the Headphone jack too, that disables internal speakers.

See attached pictures of Schematic.

// Per.
[Nexus 7 Accessories] penguinlogik:
Only if the option for audio re-routing is enabled though.
[Nexus 7 Accessories] zapro:
Yeah, but the electrical connection between the jack and the pogo-pins are permanent, there is no switch in-between these. It's a matter of software switching.

// Per.
[Nexus 7 Accessories] zapro:
I'm just trying here to see if anyone has an idea about this, as this is related to the Pogo-pins i think it's fitting to post in this thread.

I'm going to mount my Nex7 i my car. I need to charge it when ignition is turned on - go to sleep when ignition is turned off, and i need to be able to use an USB DAC.

I've tried the Timur Mehrvarz kernel on an otherwise stock 4.2.1 and then I have USB DAC working with a home made OTG cable.

In this configuration i'm charging the Nexus 7 trough the USB plug, and still using the USB DAC at the same time. This works until the power is cut. I do not want to charge the tablet all the time, as this ruins the battery.

I had the idea of charging the Nexus 7 from the Pogo-pins and then attach the USB DAC to the OTG cable and do it this way. Unfortunately, when i've installed a Kernel that enables USB DAC, the state "AC Charging" keeps being active when power from the Pogo-pins are disconnected, rendering the tablet in a state where it never goes to sleep, and drains the battery.

The old hack on the 4.1.2 kernel by modifying the asound.conf is no longer possible on the 4.2.x kernels, it uses a completely different audio system.

Anyone with any hints on what I could try ?

In short this is what i need:

1: USB DAC - Hot plug is not needed, reboot while being connected is fine with me.

2: Able to differentiate Charge from standby, rendering the Nex7 to turn on automatically when power is applied, and go to sleep when power is removed.

3: The tablet does not actually need to supply power to the DAC, i can supply that externally if that changes anything.

// Per.
[Nexus 7 Accessories] penguinlogik:
Modify the OTG cable to transmit only data+/- and have a separate 5v suppy for the DAC and the OTG cable (thats also tied in with the pogo pins). The tablet turns on automatically when docked, however I haven't found a way to keep the screen on (without another app), so a switch for the Pogo pins to turn on and off the charging. The tablet does not turn off automatically when power is removed though (until screen timeout). Also I believe that the tablet does a "float charge" where it stops charging at 100%, waits until it drops to 95% or so (not exact) then recharges again, however this is also bad for the battery in the long run.

I'm not sure if OTG would work without +5v to the pins though, but the AC Charging state might just be a kernel problem and would need to be fixed.
[Nexus 7 Accessories] zapro:
UPDATE!

I think i got it working now! - Timur updated his Kernel to do just what i liked!

Have a look here:

http://mehrvarz.github.com/nexus-7-kernel-download-page/

I tried the timur-usbhost-2012-12-23-jb42-fi.zip for Fixed Installation. I have yet to try the "Mobile" versions - I really cannot seem to find the documentation that states the difference, probably something about things need to be plugged in at boot - whatever...

I made a OTG-Y-Cable like this (lower drawing):

http://www.ida-and-pingala.com/imag...-inch/DIY-OTG-Adapter-&-DIY-OTG-Y-Adapter.gif

It works perfectly - When supplying power to the adaptor the Nex7 says "Charging (USB)" and the USB DAC is powered.

After wakeup "Play" in my music player needs to be pressed, and the music flows. It's important to note that is Audio playback is not disabled before power is cut, the Audio malfunctions, and you need to stop the Audio playback, re-plug the OTG cable and resume playback - This seems to work quite good.

So all in all, i'm a happy camper!

Stopping/starting playback of Audio can be controlled by some Tasker settings, since i now have the "Charge (USB)" I can use to detect if Playback needs to be enabled. To stop playback before power is cut, i'm going to use my Controlled NFC tag i wrote about here: http://www.blog.zapro.dk/?p=309 and make that stop playback before power gets cut (main power on a timed relay)

If anyone has any info on the difference of the Kernel's regarding Mobile or Fixed installation, chime in please.

// Per.
[Nexus 7 Accessories] UncannyValley:
Thanks for clarification, that was my first thought too.

So the ~600 Ohm potentiometer (from a broken headset) and the headphone jack speaker wont do no harm.
[Nexus 7 Accessories] zapro:
Yep, no problem doing that.
[Nexus 7 Accessories] UncannyValley:
Ok, but i have another problem:

when the N7 is plugged in and I touch it, theres sometimes a clicking noise on the speaker, no matter if i touch the display or the frame.

Also I did experience bugged touchscreen input, which is supposed to come from differentiating potentials.

So I wonder could it help to ground connect the frame?

Also my 600~Ohm potentiometer (volume control from a headset) isnt strong enough. Volume goes from loud to very loud :) Needs more Ohm. Anyone found a suitable potentiometer?
[Nexus 7 Accessories] katraska:
Hi, I have made my own dock charging with pogo pins, and it works fine.

However, now is not possible to charge the Nexus with USB connector if the tablet is powered. If switch it off, i it is possible to charge with USB connector.

I am sure about the correct polarity connection in the POGO pins, since the pins are soldered to the charger, and i have not modified it.

The charger voltage has been verified (5.1 volts without load, and about 4.9 volts when connected to the nexus)

Any idea?

Thanks
[Nexus 7 Accessories] katraska:
More news:

I cannot connect the tablet to the PC via USB. The device is not detected

I can connect with a flash drive with OTG, even when the tablet is charging in the dock.

Now, when i remove the tablet from de dock, the icon indicating that the device is charging remains until i switch off the tablet.

I think that there is a software issue

Take care with pogo connections
[Nexus 7 Accessories] brad_wp:
I don't think it's software related. You probably fried something on the board around the connector. I had a similar problem with my first N7. It was plugged into a car charger when the car charger made "magic smoke" and almost caught on fire. After, I had the exact same problem you're experiencing. Wouldn't charge while powered on, no USB to PC, but USB OTG still worked. I did several factory resets to no avail, so I'm pretty sure it is/was hardware.

Sent from my Nexus 7
[Nexus 7 Accessories] katraska:
Well, I'm afraid I agree with you. I have restored the tablet, and it's still bad. However, in my case, no smoke nor wrong connections has happened. So, I must think that something is "fragile" inside the charging circuits.

I will try to get it repaired under warranty, but I will not try to charge it again via pogo pins :( at least until somebody tell us what the original dock has inside (perhaps some protection circuitry...)

Did you repair it?
[Nexus 7 Accessories] Flowyk:
how long/offten did u charge it through pins?
[Nexus 7 Accessories] katraska:
Only once, for about 10 minutes. It was about at 95% charge and I removed it from the dock at 100%

I was monitoring DC volts and AC component in the charger, and everything was correct.
[Nexus 7 Accessories] theBeachBoy:
The official dock indicates 5V, 2 Amps on the back and instructions indicate to use minimum 5V 2.0 Amps input (charger output) - see this video at exactly 15s and 56s: http://www.youtube.com/watch?feature=player_detailpage&v=X4CjB37tdRE#t=15s - , nothing tells us if it's modifying this current to charge through pogo pins or if it's only two wires pos/neg direct from the input to the pins.

Anyone know the tablet's spec for pogo charging?

I know many people just send whatever, but is it really made to get 2 amps?

---------- Post added at 09:33 PM ---------- Previous post was at 09:23 PM ----------

the dock needs 5V 2A input (so you can use your phoen provided charger as the dock does not have one) but doesn't say anything about what the pogo pin gets... until someone can read it or get us datasheets I would not want to put 2A there just in case.
[Nexus 7 Accessories] katraska:
You're right.There is no information about how to charge the device via pogo pins. However, I have been reading the SMB347 data sheet (suposedly, the circuit that controls the charge and USB), and it can be used upto 2500 mA.

Anyway, I will wait until we know what is inside the official dock.
[Nexus 7 Accessories] Flowyk:
Dock specs will be very useful ... is it for sure that gnd is at top?

I charged about minute and usb still works
[Nexus 7 Accessories] funkysam78:
I've tested with 5v 1A, it draws 820mA, also the Pogo's are independent from the USB, I had on otg in at the same time n it was working n charging
[Nexus 7 Accessories] theBeachBoy:
So plugging 2 amps would still draw 820mA... I guess it's not a good idea to plug 2amps direct.

WE'll see with the dock, but I would suspect a step down from 2A input to 5 volts 900-1000mA output.
[Nexus 7 Accessories] Flowyk:
why not
[Nexus 7 Accessories] theBeachBoy:
well it seems that it could damage the unit by the few comments above...

I have no experience with the nexus 7 charging, but I'Ve played quite a lot with hi-power LEDs.. and LED lights are very sensitive to higher currents, they draw a specific amount of mA and if you "give" them too much, they fry. Could be the same with the Nexus pogo charger... It's not because sommething draws 1 amp at 12V that you can plug it direct +/-on a car battery.
[Nexus 7 Accessories] penguinlogik:
LED lights do not pop with higher current, they pop with higher voltages. Same with charging, you can have a 5a charger, but that doesn't mean that 5a of current is flowing all the time. Its limited by the device end. IMO having a 2A charger for a ~860ma circuit would be better, as it the charger would last a lot longer and be more efficient (at 50% load rather than 86% load for a 1A charger)
[Nexus 7 Accessories] Sandheep:
Well said!

Another advantage is you would get a lot more stable voltage out of a charger operating@ half capacity. The closer you get to peak current the more unreliable your voltage output is going to be. Plus the fact that many chargers don't really have the capacity to provide as much current as they are advertised.
[Nexus 7 Accessories] Flowyk:
thats bad logic ... same as saying that electric power did fry the tablet because they use electric power when the tablet fryed ... there will be more problems
[Nexus 7 Accessories] herbert1:
I'm using a DIY dock plugged on a 2amps charger (the nexus 7 one) since several month without any problem...

As explain above by penguinlogik, what's important is the charger voltage and that's the current drained is bellow the charger max amperage.