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[HW MOD] Internal USB GPS


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#1
wooshy1

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Ok so I have noticed a few people posting about using a USB GPS dongle with the Vega so I thought I'd give it a go.

First off DO NOT attempt this if
1: you are faint hearted Posted Image
2: you do not know how to use a soldering iron.
3: you do not know how to build and deploy your own kernel.

I am not responsible for you destroying your Vega in the process of installing this mod.

No Advent Vega's were harmed in this modification. Posted Image


Check that the USB GPS dongle you buy has a linux driver. The one I have used is a globalsat nd-100s which simply renders itself as a pl2303 based usb to serial adaptor which is well supported in linux.

I have installed my GPS dongle inside the Vega and will show you below how I did it.

If you just wish to use a USB GPS Dongle externally with the USB port in HOST mode you can skip the hardware section.

Hardware Preparation:
First off follow either of the following excellent posts to get yourself a spare internal USB port.

http://android.modac...al-camera-port/
http://android.modac...hub-and-3g-mod/

For the GPS to work correctly ie be able to get a satellite fix it must be mounted down the one side of the display and then shielded.

As you can see in the images below you will need to remove a section of plastic (using a hot knife) big enough for the ceramic patch antenna, I also scratched away some of the black paint on the back of the glass so you can see the GPS LED from the front of the tablet to check if it has locked out. You can also see the plain kitchen foil I used to shield the GPS module from the lcd screen (this is important as without this shield there is too much interference to get a satellite fix). Finally the modification to the rear panel note I removed the middle retaining leg. My rear panel doesnt quite fit as flush as it did originally it only protrudes about 0.5-1.0mm in the centre. This could be because in my haste to remove the usb plug from the GPS module I pulled off the data- pad so had to solder to the secondary connector on the back of the GPS pcb Posted Image. You have been warned so be careful.

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Software preparation:
As already stated the GPS dongle I am using uses the pl2303 usb to serial adaptor driver if your chosen dongle differs you will need to add the relevent driver (if not already in the kernel) and the config option.
The next step is to build support for the pl2303 usb-to-serial adaptor into the kernel simply download the kernel relevant to your rom in my case I am using the excellent HoneyIce 3.2.7 by Aero for which the kernel is in my github https://github.com/w....36_nvidia_base then add
CONFIG_USB_SERIAL_PL2303=y

to the .config file either by hand editing or menuconfig then build the kernel.

if your GPS device is fitted internally like mine add this
service usbgps /system/xbin/busybox stty -F /dev/ttyUSB0 ispeed 4800
class core
oneshot
 
setprop ro.kernel.android.gps ttyUSB0

to the init.rc in your ramdisk (again this speed is dependent on the GPS device you use)

Then deploy your new kernel, ramdisk and wifi drivers to the tablet.

If you are using your GPS externally via the USB port in Host mode, simply get a terminal app up and as su enter the following:
stty -F /dev/ttyUSB0 ispeed 4800

followed by
setprop ro.kernel.android.gps ttyUSB0

This should be all that is required however I could not get the libgps provided by ejtagle in the kernel thread to work so I did the following
download and install
UsbGPS4Droid_alpha3.apk
from http://forum.xda-dev...=1143329&page=2
it means you must run this mock location app whenever you want to use the GPS.
Maybe when I get some more time I will get the libgps working so that this app is not needed but for the moment it works and I have a GPS lock and have used it with google maps to navigate round my local area.

Hope this helps others who are thinking about this modification.

Credits for this must go to
ejtagle, rebel1 and anybody else who helped in the development of the 2.6.36 kernel
rose840, windin101 and richardmlea for the internel usb hub mod
herbert1 for the Usb4GPSDroid app.
Aero for HoneyIce 3.2.7
Anybody else I have forgot to mention.

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#2
richardmlea

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I missed this at the time you posted it and have been meaning to say "Great work" for a while. I had a go at fitting a Bluetooth GPS internally. It worked but not well because of the location and size. I considered doing what you did but decided to go with Bluetooth for simplicity of connection. You have cracked though.
Well done again,
Richard

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Richard Lea
[email protected]
Replacement Tablet Screens UK
I offer a friendly, UK Advent Vega repair service for hardware problems. Just PM or email me your requirements.
Replacement Touchscreens, LCD's and repair service for most Tablets.




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