* Supported by OpenWrt.
* Cheap and easy to buy ($20 USD from eBay).
* Has a USB host.
* With a little work, it has a serial port.
* Small form factor.
What follows is a simple hack to add a serial port to your WR703N device. In essence, you just need to solder a couple of wires to some pads onto its PCB. I’ve decided to elaborate and show you how to do this properly.
For this hack you’ll need the following:
* A couple of strands of insulated wire-wrap wire and a heavier duty wire.
* A hobby knife.
* A sharp 0.8mm drill bit.
* A jewellery file.
* A hot glue gun.
* A 4 way 0.1” male header.
* A fine tipped soldering iron, solder, and a solder wick.
* A multi-meter (DMM).
* Reasonable soldering skills and good eyes!
This instructable is aimed for electronics and robotics enthusiasts. Exposing the serial port is only useful if you plan to custom firmware (i.e., OpenWrt on it) and do some hacking. This mod will void your router's warrant and I take no responsibility if something goes wrong!
Using the knife cut the traces from the LED to the existing plated through holes.
Slowly and carefully enlarge one of the holes you just drilled by twirling the tip of the blade in it. Leave the one that designated for ground alone! You’ll need to enlarge the opening especially on the top layer of the PCB. The router’s PCB is multi-layered, so you want to make sure the newly made through hole pads don’t short to ground. Check this by dry-fitting the header and checking whether there is any resistance between the pads and ground with your DMM. Solder the header and confirm that the only pin that is shorted to ground is the one that is meant to be!
Tin the serial port pads which you are going to bring out. Strip the wire-wrap wire and tin it as well. Now carefully solder the wires to the pads. After doing this fasten the wire to the PCB with hot melt glue as I have done.
You’re almost done! Do one last resistance check with the DMM. Now power-up the device and with a bit of luck you’ll get a serial based console from the router. I’ll tell you how to re-purpose that for other things in a subsequent tutorial.