TP-link WR703n as telemetry link and camera broadcasting Part1 (preparation)

Hello,
here is the first part of a tutorial to hack and tune a small wifi/3G router to be able to broadcast the telemetry of your favorite copter control board

1. Get a wr703n

You'll find it on every good chinese online store, mine come from lightake but it can be found on dealextreme, ...
if you want to have more Ram, prefer a mr3020, which is nearly the same.

2. Open it (optional for the "next" branche firmware(see later))

I annoted few things to notice :

- the Gnd pad, need help?

- 5V pad is for powering the device if you don't want to cut the strange usb cable that is given

- Rx & Tx is for connecting a ttl 3.3v serial interface, mainport of the CopterControl board seems ok (to be checked), warning thes pad are very very small and hard to solder, once you succed in soldering them secure everything in glue.

These pad are also very usefull, not to say needed, when you brick your router (appened me twice in a day), I'll wrote later a tutorial to unbrick it in case of.

- 0 is a zero ohm resistor that I removed to plug a new antenna (see later)(optional)

- 3.3v is a testpad that make revived the router after a short, don't know why it worked, but I'll tell you how

3. choose your method : hid and serial telemetry or vcp ('next') and usb serial

3.1 hid and serial telemetry :

you'll have to solder two really small wire to the two small pad annoted TP_IN (RX) and TP_OUT (TX), and plug them respectively to the TX and RX of one of your CopterControl board port setup as telemetry (57600bds). You'll also need to give the router 5V and Gnd.

Warning : when the router is booting it is streaming the log console on the TP_OUT @ 115200bds and sending them command such as <CR> or <LF> (0x0D 0x0A) can make it enter in console mode waiting for login... so the telemetry link won't work, prefer unpluging the telemetry cable till the router hasn't booted (blue led stay solid).

3.2 Vcp and usb serial

If you have a firmware already compiled with the 'next' branche of git, there is only software to install on the router, that's all and giving the router 5V with the given usb cable (will also power up the CopterControl board). Ah yes, you'll still have to change the usb telemetry from hid to vcp...

4. Install Openwrt
plug an ethernet cable to a computer on which you'll have donwloaded the last firmware version :
Don't really remember, but I thinks mine was this one : http://downloads.ope...hfs-factory.bin
Do not choose the upgradesys one, it will brick your router.

In any case read this : http://wiki.openwrt....-link/tl-wr703n

Open a browser to http://192.168.1.1 and you'll fall on a really nice chinese interface

To flash from the Chinese web interface, at the present time you would select the last menu item on the left, and then the third submenu item. This initiates a popup with two buttons–the upper right one allows you to browse to find the file you want to flash on your PC, the lower left one initiates the flash.

wait few second until you flashed it and reboot it...

once the blue led stay solid, open a terminal an type :telnet 192.168.1.1
it should grant you with openwrt up and runing...
first thing to do is to change the IP adress of the router, so that you can plug it on your home router to give im internet access and you can still go on the web
so : vi /etc/config/network
and change it like that :

config 'interface' 'loopback'
	option 'ifname' 'lo'
	option 'proto' 'static'
	option 'ipaddr' '127.0.0.1'
	option 'netmask' '255.0.0.0'

config 'interface' 'lan'
	option 'ifname' 'eth0'
	option 'type' 'bridge'
	option 'proto' 'static'
	option 'ipaddr' '192.168.1.51'
	option 'netmask' '255.255.255.0'
	option 'dns' '8.8.8.8'
	option 'gateway' '192.168.1.1'

where 192.168.1.1 is your home router, of course... and 192.168.1.51 will be the wr703n ip adress.

On next chapter we will install all the usefull software on the wr703n stay tuned.