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Has anybody tried this: 1. Setup a powered USB hub plugged into the Micro OTG cable 2. hack the cable from right after the OTG cable to where it plugs into the hub, so that the voltage pins are exposed 3. solder in the voltage pins to a usb connector so you can plug in a normal charger [5V 2A] 4. check to see if you can use the USB hub and charge at the same time
I currently have a Asus transformer TF101 and the primary use is watching clips off a 500GB usb HDD. I really, really want to get a N7 and sell my TF101, but if charging & simultaneous host mode is not possible, I would be slightly hesitant to buy it, because I would be eating up the battery much faster than I would like.
Sent from my Nexus 7 using xda premium
An OTG cable is not for charging/connecting your device to a computer. Instead of usb micro to a male usb, it's micro to female usb, so you can plug in peripherals and flash drives etc. to your device.
Sent from my SGH-I777 using xda premium
When a normal USB is plugged in, the Nexus is in "slave" mode. Receives instructions.
When an OTG cable is plugged it allows it to be in "master" mode. Can give instructions.
Sent from my Nexus 7
Stop... MUFFIN TIME!!!
There are basically 3 types of cables you can plug into the USB port of a Nexus 7:
1. A normal USB-to-microUSB cable, plugged into a computer or a USB charger. Either way it charges, and if it is hooked to a computer the N7 is in Client Mode and you can transfer files as well.
2. High-current chargers (like the one that comes with the Nexus 7). The data lines on these are shorted together; this tells the Nexus to accept higher current on the power lines for faster charging.
3. OTG cables have the normal 4 wires on the USB end - two for power, two for data - but on the microUSB end there is a fifth connection called USBID. Normally (as when using a normal 4-wire USB cable) the USBID pin is floating, i.e. not hooked to anything. On an OTG cable, the USBID pin is connected to the ground wire. This tells the N7 that an OTG device is plugged in, which causes it to do two things: it reverses the current on the power lines - because it needs to power whatever you have plugged into the OTG cable, like a USB card reader or keyboard - and it switches the USB interface from Client Mode (which it uses when it is plugged into a computer, because in that instance the N7 is a peripheral device) to Host Mode (because in that instance the OTG device is the peripheral and the N7 is the 'computer').
There is one other option for charging: the pogo pins on the side. (The 4 pins are 5V, stereo left, stereo right, and ground.) Providing power to the pogo pins (as when it is put in a dock) tells the N7 to accept high current on the pogo pins. Momentarily connecting 5V to the right stereo channel tells the N7 that external speakers are connected and it starts driving audio out the two center pogo pins. When this is happening the charging takes place through the dock, the USB connector can be used with a data cable or an OTG device, but no charging takes place through USB when the dock is connected. (An OTG device is still powered by the N7, but current never goes the other way.)
Mechanio said:
There are basically 3 types of cables you can plug into the USB port of a Nexus 7:
1. A normal USB-to-microUSB cable, plugged into a computer or a USB charger. Either way it charges, and if it is hooked to a computer the N7 is in Client Mode and you can transfer files as well.
2. High-current chargers (like the one that comes with the Nexus 7). The data lines on these are shorted together; this tells the Nexus to accept higher current on the power lines for faster charging.
3. OTG cables have the normal 4 wires on the USB end - two for power, two for data - but on the microUSB end there is a fifth connection called USBID. Normally (as when using a normal 4-wire USB cable) the USBID pin is floating, i.e. not hooked to anything. On an OTG cable, the USBID pin is connected to the ground wire. This tells the N7 that an OTG device is plugged in, which causes it to do two things: it reverses the current on the power lines - because it needs to power whatever you have plugged into the OTG cable, like a USB card reader or keyboard - and it switches the USB interface from Client Mode (which it uses when it is plugged into a computer, because in that instance the N7 is a peripheral device) to Host Mode (because in that instance the OTG device is the peripheral and the N7 is the 'computer').
There is one other option for charging: the pogo pins on the side. (The 4 pins are 5V, stereo left, stereo right, and ground.) Providing power to the pogo pins (as when it is put in a dock) tells the N7 to accept high current on the pogo pins. Momentarily connecting 5V to the right stereo channel tells the N7 that external speakers are connected and it starts driving audio out the two center pogo pins. When this is happening the charging takes place through the dock, the USB connector can be used with a data cable or an OTG device, but no charging takes place through USB when the dock is connected. (An OTG device is still powered by the N7, but current never goes the other way.)
Click to expand...
Click to collapse
Dont forget a "y cable", which can charge and preform host mode (otg) at the same time, only at a slower charging rate. This is providing you are using a kernel that supports this function. "Otg+host mode charging"
Sent from my Nexus 7 using xda premium
I'm wondering if anyone knows if it's possible to have simultaneous OTG & charging with the use of a pogo pin charger?
For instance, plug in a usb OTG into the main microUSB charging port, and use a pogo pin charger [either make one or buy when they are available], and have a flash drive, or hard drive plugged in, and charge at the same time with the pogo pin connector?
I used to have a Nexus 7, and via a custom kernel, and a OTG charging cable [basically a regular OTG with additional power wires & connector for charger]. But I think it would be simpler to use the pogo pin approach. The only thing I'm worried of however, the kernel might disable OTG while it charges via pogo, or perhaps disable charging while OTG is enabled. I guess in this case, we would need a modified kernel to achieve simultaneous OTG and charging.
Here is a link to one of the first Nexus 10 pogo charger cables and it makes this claim:
"You still can power Nexus 10 while the USB port is otherwise occupied for data uses. It is fun & convenient to have MagNector to free up the USB port and charge faster."
http://www.ebay.com/itm/MagNector-N...ader_Chargers_Sync_Cables&hash=item20ce4990a6
So if that statement is true than the answer to your question is Yes.
eBay item is no longer available..
However, I know how sellers often make unfounded claims like that. So while it's probably a good sign, I am not convinced it's true. If anyone is fortunate enough to have a pogo charger, could you test it out with a otg cable and let us know the results?
Or if you're a kernel hacker, maybe take a look at the kernel source code and tell me what you think?
Also if anyone has a link where I could read about pogo pins for the N10, I'd like to read it. I'm interested in trying to make one, if they don't make any low-cost ones in the near future.
:bump:
mvmacd said:
eBay item is no longer available..
However, I know how sellers often make unfounded claims like that. So while it's probably a good sign, I am not convinced it's true. If anyone is fortunate enough to have a pogo charger, could you test it out with a otg cable and let us know the results?
Or if you're a kernel hacker, maybe take a look at the kernel source code and tell me what you think?
Also if anyone has a link where I could read about pogo pins for the N10, I'd like to read it. I'm interested in trying to make one, if they don't make any low-cost ones in the near future.
Click to expand...
Click to collapse
The answer to the question is ye, you can charge and use otg. Btw, http://pogocable.com/ 20$ isn't a bad price...
lKBZl said:
The answer to the question is ye, you can charge and use otg. Btw, http://pogocable.com/ 20$ isn't a bad price...
Click to expand...
Click to collapse
Just wondering, have you actually tried it yet? I remember on the n7 it would disable pogo charging when you plugged in otg. I hope n10 is different.
Swiped from my Nexus 10 using xda-developers app
I got the pogo cable in today. I plugged the usb-otg cable into the Nexus 10 with a thumbdrive connected to it. Stickmount recognized the thumbdrive and I can read/write to it. I noticed that the battery runs down while the otg is plugged in though. Running Paranoidandroid 2.99 with whatever kernel comes with that.
bd177 said:
I got the pogo cable in today. I plugged the usb-otg cable into the Nexus 10 with a thumbdrive connected to it. Stickmount recognized the thumbdrive and I can read/write to it. I noticed that the battery runs down while the otg is plugged in though. Running Paranoidandroid 2.99 with whatever kernel comes with that.
Click to expand...
Click to collapse
Does it say "Charging (USB)" or "Charging (AC)" in Settings > Battery?
mvmacd said:
Does it say "Charging (USB)" or "Charging (AC)" in Settings > Battery?
Click to expand...
Click to collapse
It says "Charging (AC)"
I know it's not the original question, but it looks like that would be possible with a modified OTG USB cable. Sounds like you already have something similar.
I was thinking about this for using my n10 for larger video recording when away from wifi. Just need to hook a battery up to the OTG while its plugged into the thumb drive. It takes a charge off my laptop when connected via the otg usb, so it should work as well with the correct setup voltage/wiring .
I would also like to know the pin designation for the pogo plug. If you can do the same setup as the one above, with the pogo... There would be less chance of damage to the tablet on the go......
metaled222 said:
I know it's not the original question, but it looks like that would be possible with a modified OTG USB cable. Sounds like you already have something similar.
I was thinking about this for using my n10 for larger video recording when away from wifi. Just need to hook a battery up to the OTG while its plugged into the thumb drive. It takes a charge off my laptop when connected via the otg usb, so it should work as well with the correct setup voltage/wiring .
I would also like to know the pin designation for the pogo plug. If you can do the same setup as the one above, with the pogo... There would be less chance of damage to the tablet on the go......
Click to expand...
Click to collapse
I know a nonstandard OTG cable [a OTG charging cable, basically the same as a regular one, except it has female USB only connected to the charging pins] and a modded kernel allowed for simultaneous OTG + charge on the Nexus 7, but I'd rather not have to deal with that, as getting a separate pogo charger seems like a better option.
mvmacd said:
I know a nonstandard OTG cable [a OTG charging cable, basically the same as a regular one, except it has female USB only connected to the charging pins] and a modded kernel allowed for simultaneous OTG + charge on the Nexus 7, but I'd rather not have to deal with that, as getting a separate pogo charger seems like a better option.
Click to expand...
Click to collapse
It has to be a moded kernel to access the data in read/write mode? Nothing to do with charging, and correct?
What I was considering is a battery/usb hub combo. One that plugs into the micro usb port and the battery actually has a female usb port for the thumb drive (need root to write to the drive, but not to stream from it). Amazon carries lots of external batteries with micro usb connection and the female usb port.
I agree, the pogo would be much simpler and still allow data through the micro usb.
The pogo would be much better for portability for this type of use especially if it allows for faster charging. If no one has the pin layout, guess I'll wait to get mine and test them myself. 6 pins on the n10 itself so it's not a standard usb pin setup?
metaled222 said:
It has to be a moded kernel to access the data in read/write mode? Nothing to do with charging, and correct?
What I was considering is a battery/usb hub combo. One that plugs into the micro usb port and the battery actually has a female usb port for the thumb drive (need root to write to the drive, but not to stream from it). Amazon carries lots of external batteries with micro usb connection and the female usb port.
I agree, the pogo would be much simpler and still allow data through the micro usb.
The pogo would be much better for portability for this type of use especially if it allows for faster charging. If no one has the pin layout, guess I'll wait to get mine and test them myself. 6 pins on the n10 itself so it's not a standard usb pin setup?
Click to expand...
Click to collapse
No, on the Nexus 7, if you plug in a OTG cable [which basically grounds a certain pin, the only difference between micro OTG and micro to full size USB adapter], it disables charging through power pins, because it needs to send power to OTG device, for example, a flash drive. It needs +5V power.
So the kernel mod was to disable the output of power, so that it could instead receive power and charge, from the charger. [The charger also 100% powering the OTG device]
Even if you have an externally powered hard drive, it needs power to turn on, even if it uses a wall adapter for the actual power to run the device.
Here is the kernel I was talking about: http://mehrvarz.github.com/usb-host-mode-power-management-nexus7/
it was made by a rootzwiki user. some discussion here: http://forum.xda-developers.com/showthread.php?t=1934722
Check the images of the USB hub on the 1st link.
Just for the heck of it I plugged a USB cable connected to my PC into the Nexus 10 while the pogo was also connected. The Nexus 10 showed up on the PC as it normally does in the file explorer and I can transfer files back and forth as usual. I went to Settings -> Battery on the Nexus 10 and it showed "Charging AC". I then unplugged the pogo cable and the status changed to "Charging USB". Plugged the pogo back in and the status switched back to "Charging AC". Then to make sure the pogo was actually doing the charging, I watched 2 hours of Netflix with the screen set to full brightness. The battery went down only 2%, so I'm pretty sure the pogo was doing the charging.
Sv: [Q] Pogo pins and OTG question [simultaneous charge & OTG?]
Thanks for your test. However with Nexus 10 connected to pc it is not in otg/host mode. You need to connect for example an usb memory with a otg cable to test if charging work with host mode enabled. There seems to be some discussions going on claiming pogo charging is disabled in host mode on Nexus 10 as well. It would be really really stupid if that's the case and I can't for the world figure out how they could put this limitation in the kernel.
Skickat från min HTC Desire via Tapatalk 2
Johan1976 said:
Thanks for your test. However with Nexus 10 connected to pc it is not in otg/host mode. You need to connect for example an usb memory with a otg cable to test if charging work with host mode enabled. There seems to be some discussions going on claiming pogo charging is disabled in host mode on Nexus 10 as well. It would be really really stupid if that's the case and I can't for the world figure out how they could put this limitation in the kernel.
Skickat från min HTC Desire via Tapatalk 2
Click to expand...
Click to collapse
Yes I tried that and the pogo would not charge.
EDIT: I bought a couple of OTG Y-cables on ebay (1 male micro usb end, 1 female micro usb end and a female usb end) to play around with when I saw they had a fix for the Nexus 7. I tried one on my Nexus 7 (PA rom and Timur kernel), connecting the female usb to a powered usb hub that has 16gb sdhc card plugged into it. Then connected the female micro usb end to a spare micro usb charging cable and the other end of the charging cable to the usb hub. The male micro usb end gets connected to the Nexus 7. I fired up the Nexus 7 while in the Asus pogo dock I bought for it and it charges the Nexus 7 while also allowing the OTG connection. I tried the same setup with my Nexus 10 (PA Rom, Ktoonez kernel) and pogo cable and it worked. The Nexus 10 charges through the pogo cable while the OTG works also. With the usb hub I'm using with the Nexus 10, I had to plug the charging cable into a charger wall wart. I don't think the old hub was putting out enough power to power the usb device. I let them both run over a day like this. Ran some RomToolBox app backups on both them and they both are charging on the pogo pins while doing so. If you go to system settings -> battery it shows "Charging AC" on both.
The galaxy nexus already has a custom kernel that supports OTG + charging (via a y-cable):
http://forum.xda-developers.com/showthread.php?t=1835720
In that thread (and the link in the OP there) there are discussions about porting that kernel to the nexus 7. Also, this modified kernel is (currently) for 4.1.2. Unfortunately I am not smart enough to do this myself (especially we are now dealing with the pogo cable and the USB); I do hope to let everyone -- especially the developers! -- knows about the possibility in view of the gnex kernel.
Is this an issue only with Disk Media over OTG, or is it with anything (controllers, etc.) over OTG?
If anyone is interested read my edit a couple of posts up.
Sv: [Q] Pogo pins and OTG question [simultaneous charge & OTG?]
It says AC charging even though it's not actually charging. Confirm this with for example battery monitor widget.
Skickat från min HTC Desire via Tapatalk 2
I have an andrid. Stick mx2 imito and I have a powered USB hub but I can't configure how I am meant to to get it to read from the hub. I have 2 ports on the stick, one full sized usb and one mini usb .
And In terms of devices I have my keyboard I want to add
1 external usb hard drive
And if I can get it to work a USB wifi dongle
Huh!
Since there is only one full sized USB port, I would think that is the solution. That's how it runs on mine anyway. Connect all your devices to the powered hub. Should be straight forward
So I would need a usb cable male to make? To connect to the hub. Do they exist ? I will try find the cable .
i cantget it to work
so the large usb port. i need a cable from that to connect to the hub? usb port
but i dont have a usb port with the same end? male to male etc
Get a USB powered hib
wakkaday said:
i cantget it to work
so the large usb port. i need a cable from that to connect to the hub? usb port
but i dont have a usb port with the same end? male to male etc
Click to expand...
Click to collapse
The hub will come with one male USB to connect to the stick.
http://gadgets.softpedia.com/images/news/How-to-Charge-your-USB-Devices-Quick-and-Easy-4.jpg
Make sure to get a powered hub so that all the devices can be supported properly.
gsurath said:
The hub will come with one male USB to connect to the stick.
http://gadgets.softpedia.com/images/news/How-to-Charge-your-USB-Devices-Quick-and-Easy-4.jpg
Make sure to get a powered hub so that all the devices can be supported properly.
Click to expand...
Click to collapse
this was an old hub i had, i dont have that wire. its a mini usb to full usb type connection isn't it?
Plenty of such options available
Here is another on ebay. Just search for powered USB hub and choose one
http://www.ebay.com/itm/10-PORT-USB-2-0-EXTERNAL-HUB-W-POWER-ADAPTER-FOR-PC-MAC-WITH-cable-SILVER-/370772094009?pt=US_USB_Cables_Hubs_Adapters&hash=item5653bd2c39
gsurath said:
Here is another on ebay. Just search for powered USB hub and choose one
http://www.ebay.com/itm/10-PORT-USB-2-0-EXTERNAL-HUB-W-POWER-ADAPTER-FOR-PC-MAC-WITH-cable-SILVER-/370772094009?pt=US_USB_Cables_Hubs_Adapters&hash=item5653bd2c39
Click to expand...
Click to collapse
ok great, so the port next to the power socket, is the cable i need to attach to and from the imito android stick? so that will be the main one and any other usb devices can go on the hub.
m confused on where i need to connect from on the android stick. which has 1 full sized usb, 1 mini usb otg socket and 1 mini usb (power)
It should also be possible to modify a USB hub to back feed power to the HDMI stick.
You would then power the hub with a sufficiently large USB power supply to power both the stick and all of the USB devices. In most cases, a single 2.1 Amp USB "wall wart" would work to power everything, unless you are really running something outrageous.
My NX003 (Same as MX1) can be powered from either the dedicated USB power jack, or the MicroUSB (OTG) connector.
So to build something like this, here is what I would do:
1. Obtain a USB hub I was willing to modify (destroy, as far as any other use is concerned)
2. Disassemble it.
3. Remove the input (Host) cable or connector.
4. Attach a short cable with a MicroUSB plug. Connect all 4 wires correctly.
5. Find "The diode" - Buy "The diode" I mean the one that that allows USB power to flow from the host to the peripherals when used in non-powered mode, but prevents power from flowing upstream to the host when an external power supply is used. (see referenced link).
6. Remove this diode, and replace it with a wire, jumper, or solder bridge.
7. Ensure all power circuity in the hub can handle 2 amps. Add solder to traces, or add jumper wire if needed to beef up current capability.
8. Reassemble, and clearly mark so that this hub is never used with anything else.
If the HDMI stick were powered via a coaxial connection, but is still powered by 5 Volts, I'd add a lead and coaxial plug off of the +5 in the hub. you'll have 2 wires, but it will still work. (Watch polarity.)
I have done this successfully for a prior, similar project. Reference Here: (Scroll to section about power.)
http://linuxslate.com/N770DockingStation.html
So why don't I actually do this to power my NX003? I did it an easier way. I bought a Tronsmart Prometheus. It has 3 full USB ports built-in.
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Linuxslate said:
It should also be possible to modify a USB hub to back feed power to the HDMI stick.
You would then power the hub with a sufficiently large USB power supply to power both the stick and all of the USB devices. In most cases, a single 2.1 Amp USB "wall wart" would work to power everything, unless you are really running something outrageous.
My NX003 (Same as MX1) can be powered from either the dedicated USB power jack, or the MicroUSB (OTG) connector.
So to build something like this, here is what I would do:
1. Obtain a USB hub I was willing to modify (destroy, as far as any other use is concerned)
2. Disassemble it.
3. Remove the input (Host) cable or connector.
4. Attach a short cable with a MicroUSB plug. Connect all 4 wires correctly.
5. Find "The diode" - Buy "The diode" I mean the one that that allows USB power to flow from the host to the peripherals when used in non-powered mode, but prevents power from flowing upstream to the host when an external power supply is used. (see referenced link).
6. Remove this diode, and replace it with a wire, jumper, or solder bridge.
7. Ensure all power circuity in the hub can handle 2 amps. Add solder to traces, or add jumper wire if needed to beef up current capability.
8. Reassemble, and clearly mark so that this hub is never used with anything else.
If the HDMI stick were powered via a coaxial connection, but is still powered by 5 Volts, I'd add a lead and coaxial plug off of the +5 in the hub. you'll have 2 wires, but it will still work. (Watch polarity.)
I have done this successfully for a prior, similar project. Reference Here: (Scroll to section about power.)
http://linuxslate.com/N770DockingStation.html
So why don't I actually do this to power my NX003? I did it an easier way. I bought a Tronsmart Prometheus. It has 3 full USB ports built-in.
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Click to expand...
Click to collapse
Thank you for the informatiom, but its a bit too technical for what i want... but i appreciate you efforts in writing this.
my stick can also power via both usb ports (mini) i have connected the cable from the stick to the hub which has been powered to the mains and it works, but the problem i have is when i put another usb device in the hub, it doesnt detect it e.g. keyboard wireless and i don't think the device has enough power to run my usb 2.0 portable harddrive (not main powered) - how can i get this to work? i have tried connecting this directly to the stick, but it just makes a beep sound. im guessing its lack of power... and i was hoping a hub would help.
my hub is powered 3.5 or 4 watts i believe...
Strange
Wakkaday,
This is very strange. On my MK802III I connect the powered USB hub (4 ports) to the full USB port.
I connect my bluetooth keyboard, 1 TB HDD and USB ethernet to the hub.
I power my Android stick using the 4rth port in the USB hub.
If I want USB audio, I replace the Ethernet/HDD with a USB audio peripheral.
All my peripherals work right out of the box. The only thing I am considering now is to have a separate power supply to the Android stick so that I can use all 4 ports on my hub.
It seems your device is not supporting the peripherals? Are the working when you connect directly?
gsurath said:
Wakkaday,
This is very strange. On my MK802III I connect the powered USB hub (4 ports) to the full USB port.
I connect my bluetooth keyboard, 1 TB HDD and USB ethernet to the hub.
I power my Android stick using the 4rth port in the USB hub.
If I want USB audio, I replace the Ethernet/HDD with a USB audio peripheral.
All my peripherals work right out of the box. The only thing I am considering now is to have a separate power supply to the Android stick so that I can use all 4 ports on my hub.
It seems your device is not supporting the peripherals? Are the working when you connect directly?
Click to expand...
Click to collapse
I'm also trying to use a powered 4 port usb hub with my android stick, but it doesnot recognises the hub. Do i need to have any usb host drivers or change any setting to get it work? My stick is on Android ICS.. Thanks in advance
I am using a Seek Thermal imager via the N10's USB OTG port. My battery is old and takes a dive when I use the imager. Roughly only an hour of use before it kills the battery. Obviously the thermal sensor draws power from the n10's battery.
I think I read somewhere that I cannot use the pogo plug to charge while using the otg. Is that correct? That would have been an ideal solution.
Would it be possible to use an external battery (14000mAh USB battery supply) and feed/splice it into the usb otg cable with the imager? What about a 4 port USB hub using the battery and thermal sensor plugged into the otg? Not sure since I don't think it works like a USB host and don't think you can back feed power via USB host port.
Any ideas? Could any of this work? Thanks for any suggestions!
Ed