[USBHOST] DIY USB Host dongle

pokey9000 · Jul 1, 2011

Problem, Samsung?

Recipe:
1 dock connector from Kineteka
2 10k ohm resistors - needs to be 20k, a single 22k is too much
1 donor USB extender cable
Various heat shrink, tape, etc to taste

Pinout here. With the connector plugged into the Tab, and the Tab oriented with the chat camera on top and the connector on bottom, pin 1 is to the left of the connector.

Chop off the plug end of the extender, separate out the wires, cut / strip / tin. Cut off the shield. Slide on the plastic shroud for the dock plug and a piece of heat shrink for strain relief. Don't forget this or you'll have to undo the whole thing (like I did). You might also want to cut thin heat shrink to go around each wire to protect it from shorting at the connector pins.

Solder the two resistors in series and put them between pins 13 and 15. This tells the Tab to go into OTG host mode. Be creative. Surface mount parts might be better here.

Solder:

ground (black) to pin 1
green (D+) to pin 3
white (D-) to pin 4
red (+5V) to pin 6

Test this out before shrinking the pins by plugging into the Tab along with a USB key. If it works, you should get the message above.

Once it works, put the connector shield, spring clip, and shroud on.

All said and done, this comes out to about half the price of the Samsung adapter, but at the expense of some elbow grease and potential unreliability. I expect clones will be showing up on eBay someday though, so if I've done anything useful here it's to entice our friends in China to start their assembly lines.

mbh87 · Jul 1, 2011

Clean it up and start selling them imo.

pokey9000 · Jul 1, 2011

mbh87 said:
Clean it up and start selling them imo.

Better?

Taken before I have to ugly it up with a bit of hot glue. The connector housing is too shallow to fit the resistors and make a good strain relief with heat shrink. I also noticed that the retainer ring that holds the housing together pops right off when you unplug the connector. A little super glue needs to go there too.

NyPlaya513 · Jul 1, 2011

Nice job dude specially since they are taking forever to release the damn thing

JStar1033 · Jul 1, 2011

Lol. This is awesome goodjob. Might have to try this out

khanable · Jul 1, 2011

Well played

I'll give this a shot

time_shock · Jul 1, 2011

i'm hoping that the connector can allow you to utilise many of the pins at once.. i'm thinking of designing an all in one connector that has USB host/OTG connectivity and allows me to charge the device and still allows me to use HDMI/component video out

used2hvatreo · Jul 1, 2011

time_shock said:
i'm hoping that the connector can allow you to utilise many of the pins at once.. i'm thinking of designing an all in one connector that has USB host/OTG connectivity and allows me to charge the device and still allows me to use HDMI/component video out

I will pay you infinity for that, give you my firstborn, whatever you want. But seriously, what use is a "media dock" if you can't charge while I are passing hdmi thru.

Back on topic, nice job OP, that is my new weekend project

nemir · Jul 1, 2011

Nice job.

Since I don't have a galaxy tab 10.1 . I have an idea :

Is it possible to use female female usb adapter for the GT ?

does any GT10.1 owner verify whether or not this method is working?

pokey9000 · Jul 1, 2011

nemir said:
Nice job.

Since I don't have a galaxy tab 10.1 . I have an idea :

Is it possible to use female female usb adapter for the GT ?

does any GT10.1 owner verify whether or not this method is working?

Nope, won't work. With this you won't get the 5V power from the tablet, and you won't have the resistor on the ID pin to tell it to go into OTG mode. I suppose you could provide your own 5V power to the device, and hack the kernel to force it into OTG. But that's probably as much trouble as building a cable anyway.

ericlmccormick · Jul 1, 2011

This is awesome! Do you know if it will handle only one item at a time or could you hook a hub to it and run like a hard drive and keyboard at the same time?

pokey9000 · Jul 1, 2011

ericlmccormick said:
This is awesome! Do you know if it will handle only one item at a time or could you hook a hub to it and run like a hard drive and keyboard at the same time?

Haven't tried a hub yet, but I'll do so when I get home later. The Transformer has multiple ports on its dock so presumably that should be ok. There is a power budget limit though, since I got a dock warning about overcurrent when I tried a USB powered hard drive. A powered hub might fix that.

ericlmccormick · Jul 1, 2011

If you create a cable that charges the Tab while using it in host mode, you could probably pull the power off the charging cable instead of from the accessory pin.
If doing that, might want a selector switch or diode to keep current from flowing into the accessory pin.

I ordered a few of the 30pin connectors yesterday and I am starting my designing now for my "docking station". I am trying to figure out if I will have 1 or 4 USBs on it.

dsh897 · Jul 1, 2011

pokey9000 said:
Haven't tried a hub yet, but I'll do so when I get home later. The Transformer has multiple ports on its dock so presumably that should be ok. There is a power budget limit though, since I got a dock warning about overcurrent when I tried a USB powered hard drive. A powered hub might fix that.

Omg thankyou so much, I've been waiting for this. i was missing the two 10 ohm resistors!!!!!
Already cut up a USB and galaxy cable trying this..

will try this when i get home. im at work. let you know what i find

joedoe · Jul 2, 2011

pokey9000 said:
Problem, Samsung?

...

Recipe:
1 dock connector from Kineteka
2 10k ohm resistors - needs to be 20k, a single 22k is too much
1 donor USB extender cable
Various heat shrink, tape, etc to taste
...

Why you didn't you use one 20K 2% ohm resistor instead of two 10K ohm?

pokey9000 · Jul 2, 2011

joedoe said:
Why you didn't you use one 20K 2% ohm resistor instead of two 10K ohm?

I didn't have a 20k resistor on hand, and 20k isn't a common value in smaller resistor kits. The most readily available values in the 10k range are usually 10k, 22k, and 47k.

pokey9000 · Jul 2, 2011

pokey9000 said:
Haven't tried a hub yet, but I'll do so when I get home later.

Sure enough, with a powered hub I can hook up a USB stick, a USB powered hard drive, and a mouse. I tried a USB audio adapter as well as a 360 wireless controller via the PC USB wireless adapter, both were unrecognized. I think I remember hearing that the latter was explicitly unsupported, though I figured I'd try.

Disks show up in /sdcard/usbstorage/sda /sdb ... for as many drives as you plug in.

used2hvatreo · Jul 2, 2011

pokey9000 said:
Sure enough, with a powered hub I can hook up a USB stick, a USB powered hard drive, and a mouse. I tried a USB audio adapter as well as a 360 wireless controller via the PC USB wireless adapter, both were unrecognized. I think I remember hearing that the latter was explicitly unsupported, though I figured I'd try.

Disks show up in /sdcard/usbstorage/sda /sdb ... for as many drives as you plug in.

So does HDMI share any of the same pins as the USB? I ask because I am gonna piece together a hub and then add an HDMI cable to that, and then plug that into the media dock, and then it will be a true dock. Just need to get power for charging involved in that mix

inline4 · Jul 2, 2011

can you try hooking up an usb microphone? I'd like to see if they will work and how well. I have a samson go mic that I wouldnt mind using as a recording tool.

Framedtrash · Jul 3, 2011

Doesnt the orginal galaxy tab's hdmi dock work on the 10.1 i saw vidos of it working on the google io version should be easy to add a switch and usb to it

[USBHOST] DIY USB Host dongle

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