The Making of a Beast: WRT54G Mods, Part One

The WRT54G is one the most versatile routers; having a cheap price and a bunch of alternative firmware for it. One can find them at swap meets and second hand store all over the US. The can be used as access points, routers, bridges, repeaters and sometimes as all the above. This instructable will not go into the firmware aspect of the router, nor will it go into antenna desgin; the instructions I provide are a quick and dirty way to create a beast out of your WRT54G.

My entire want is for my WRTs was to be used as a long range repeater. I also wanted to make it Power-Over-Ethernet (POE) so I could put it some where electricity was hard to acquire. CAT5 cabling allows for 48v and 350mA over two of the four pairs, totaling in around 16w of power. The WRT54G use a 12v 500mA adapter, so at peak operating it is using 6w of power. By no means is this PoE standards ( please red up on PoE step 9); however, the router will be operating with PoE. Since in my case I will not be using any cross-over cabling I will eliminate a diode bridge. When we arrive at that part I will explain the purpose and function so one can decide if they need diodes in their project. This will allow me to network this out 100meters from my house and bridge and repeat another signal as well.

This instructable is crude and full of no-nos, so take it as a lesson in how you can modify your router by voiding the warranty. This was a quick solution to a problem I was facing and I took pictures while doing it. There are better ways, but this worked :)

Part Two is here

Step 1: Tearing It Down!!

First let me state the following: AS SOON AS YOU BREAK THE WARRANTY LABEL YOU ARE ON YOUR OWN. EVERYTHING AND/OR ANYTHING THAT HAPPENS FROM THAT POINT ON IS YOUR RESPONSIBILITY.

The v8+ opens up very simply. Two small tabs are really the only thing holding it together. Take the feet off and use a small screwdriver and pop the front off. After that it prety much falls apart. Bring the top back; two screws in the center of the board need to be taken out.

Now lets get rid of those awful antennas.

Step 2: Losing the Antennas!

Find the point where the thin coax join to the board. Do not just cut them, instead lets de-solder them off the board. I had to use a 60w solder iron to de-solder, so speed is essential to components on the board. Quickly heat up and suck up enough solder that you can pluck the wire out. I use a piece of sand paper to clean up any protection covering around the joints. Do not worry about the excess solder left on the board, we will be using that later. Also beware of joining the to points, one connects to the core of the coax (little one) an the other (big one) the ground.

As some of you might be asking. There is places on the board for antenna jacks. Look very close at the layout of the components and you will see missing resistors and capacitors. The routing would need to be completely re-worked, and would be to much work and expensive equipment to do.

Step 3: Eliminate the Power Jack.

This is somewhat optional; the reason I take it out is so I never will mix it up. With out a plug, I know that this is my PoE router. It also gave me room to make a fan plug.

Some more de-soldering skills are needed here. Simply remove the power jack, leaving three empty holes in the board. If you were planning on keep it, de-solder the back side to expose holes in the pin where wires could be soldered to.

Step 4: Wiring the Power

First step here is to obtain some 22awg solid wire. CAT5/6 solid core wire will do the trick; just make sure it is pure copper not copper-clad aluminum. If you can obtain it some Lucent technology silver wire works great.

Second, cut two pieces about 4" in length, strip them about 1/4", and make a loop(hook) in one end.

Solder each on the board, positive is the center pin; so it would be the front (toward front of router) hole. The negative is the side and back hole. I used orange/positive and white/negative. If unsure look and the power adapter, keep it unplugged and put the power jack that you removed on it and figure out how it works.

Next is soldering the wire to the Ethernet port pins. With the board upside down, like in the pictures, #1 pin is the farthest to the right, odds toward you and evens above, #8 would be the last one on the left so: 8 ' , ' , ' , ' , 1. You also have the decision of which port, I used the WAN but and LAN port could be used as well. The positive wire (orange) will be soldered to both pin 4 & 5 and the negative to 7 & 8. you should be able to tell these pins apart since they have no pathways on the board connecting them. these are the blue and brown pairs in CAT5 and are unused in 100BaseT. We will be using both wires of each pair for power transfer.

DIODE USAGE: If you want some protection use diodes inline on each positive and negative wires. This will protect the router in case of any reverse voltage happens.

When soldering is done, make sure you did not nick or solder the pathways around the pins. A dab of hot glue will help ensure nothing will ground out.

For more info on CAT5 and PoE, wiki them.

Step 5: A Simple Power Injector.

For a simple power injector: use a chunk of CAT5, add a 8P8C plug leaving the brown and blue pairs out. Wire in T568A or T568B (wiki if you don not know them). Then terminate all the pairs in a 8P8C jack, using what ever standard you picked. Double check, then double check again. The use it to connect a network patch and see if it works before connecting power. When everything is right, connect 12v 1/2A to the blue(+) and brown(-) pairs.

For a good wiring write up:http://www.lanshack.com/make-cat5E.aspx

Step 6: A Cleaner Power Injector.

First, we will need to 8P8C jacks (RJ45), one could use wall jacks, but I would rather make a nice neat box for this injector. So I will de-solder two jacks from old ISA networking cards, one could order them from Mouser or DigiKey; yet, that is no fun and cost money.

Once you find some old card, off a wall of shame or junk store, go through the process to get them off via de-soldering and not damaging them if possible.

Next drill and mount them both onto a small PCB board, I used the small square ones that Radioshack sells in pairs for $2. Drill and mount the power jack.

Start off my solder on pair of the CAT5 at a time. I used T586A standard. So striped green on pin one, solid green pin two. Then orange pair orange stripe on pin three and solid on pin six.

Patch into network and see if there is throughput. If so, next:

Then solder the power jack, blue pair on positive lead and brown pair onto the negaitve lead. Then blue striped on pin five and solid on pin four, Brown striped on pin seven and solid on pin eight. Wiki TIA/EIA-586-A if you have any questions.

Patch to port being used for power and and plug it in. If the Router powers up, then patch to network, check ping, and log into the router to see if everything is working.

If so place everything in a neat project box, it might need some saw or razor blade work, to make room for each plug.

NOW REMEMBER THIS: this PoE in only for this router, network appliances could use a range of different voltages, so keep that in mind if you are looking to expand you networks PoE.

Step 7: Heat Sink and Fan.

First finding a heat sink that fits the broadcom chip is impossible. Try locating a co-processor (or GPU) heat sink off a mother board and cutting it to shape of the chip with a hack saw and vise. That is all it needs, if you are really working the unit hard I doubt it would ever over heat, this will help prevent it though. De-burr it with sandpaper or a Dremel, clean it real good and use a silver type of heat sink paste to attach the heat sink on top of the chip.

Second, scavenge something with jumper pins on it (or buy some sort of plug you like). I used the old ISA network card I stole the RJ45 jack from. De-solder and make sure you have some sort of spacer. Next drill the board to take the pins, one next the positive and one by the negative; where the power jack was located before. And solder in place.

Wire you cooling fan (12v) with a plug that fits, and try it out. Mount the fan on your unit how you see fit.

Step 8: New Antenna Mounts.

Pick a coax of choice, I like RG-58 style but low loss: LMR 195. What I had though was a AWM 1354 which is a great coax, made for appliance hook up, the copper core is pretinned for easy soldering. It is really up to you, and research it well if you want really good performance.

Solider two 3"-4" tails onto the main board where the previous antennas were. Make sure none of the braid makes contact to the core. It can be a a tight job.

Next modify the case to accept new adapters, I will be using a BNC type, well becasue I love BNC connectors (it willl lower my gain just a tad); however you will probaly want to use a Female RP-TNC connector not BNC like me, the TNC has way better performance over the BNC. I'll be making my own antennas so BNC is fine for me. Another decesion that you have to make on your own. Take out the old junk one, saw off any extra plastic. Find a drill it that is the size of the connector you will be using and hand drill it. Mount and solder the tails from the board on to the new jacks.