Hacking a USB Port Onto an Old Router

Sometimes hacks don’t have to be innovative to be satisfying. We thought that [daffy]’s instructions and video (embedded below the break) for turning an old WRT54G router into an Internet radio were worth a look even if he’s following a well-traveled path and one that we’ve reported on way back when.

The hack itself is simple. [daffy] locates unused USB data lines, adds in a 5V voltage regulator to supply USB bus power, and then connects it all to a USB sound card. Hardware side, done! And while he doesn’t cover the software side of things in this first video, we know where he’s headed.

The WRT54G router was the first commodity Linux-based router to be extensively hacked, and have open-source firmware written for it. If you’re using OpenWRT or dd-wrt on any of your devices, you owe a debt to the early rootability of the WRT54G. Anyway, it’s a good bet that [daffy] is going to find software support for his USB sound card, but we remain in suspense to see just exactly how the details pan out.

Our favorite WRT54G hack is still an oldie: turning a WRT54G into the brains for a robot. But that was eight years ago now, so surely there’s something newer and shinier. What’s the coolest device that you’ve seen a WRT router hacked into?

24 thoughts on “Hacking a USB Port Onto an Old Router

    1. Off topic but I still have one that we used back in the day for troubleshooting inductors in RF circuits. A plastic with a small magnet in one end and a copper bar in the other. You waved the ends near the suspect coil in turn and observed what impact it had. I found it of limited use, but other swore by it.

  1. I once saw one of those small travel routers loaded up with a openWRT, a USB hub, then USB storage, a keyboard, and a USB monitor. It took some extensive kernel hacking, but the guy got a *proper* Linux desktop with GUI running.

    1. I aslso saw someone rescue a router from the dumpster, add a usb port, a usb hub, a usb drive (needed more swap and storage), install python, install octoprint, plug in a 3d printer, and run the printer off an octoprint server running on the router.

      1. That’s really cool — honestly, with those solder pads — and my skill level — if I needed more than one USB port, that’s the way I’d go (adding a USB hub, instead of trying to solder all four of those data pins).

  2. Couple of additional thoughts:
    1.) Voltage Regulators drop the voltage by dissipating heat — you may find that your hot glue ends up reflowing over time — I recommend using epoxy instead of hot glue near heat generating components (also not gluing things to those components anyway, so that they can be convection cooled). — If you want to use hot glue, get a 30W or higher glue gun — and only use the high-temperature glue sticks.

    2.) Find another test lead for your multimeter! — if it’s not the removable kind, just solder it on (use some same color heat shrink on the solder joint, and you’ll hardly even notice!) — or maybe an alligator clip? — heck, even just exposing a bit more wire there, tinning it, and throwing some heat shrink on it would be a little better than just using the bare wire!

    1. Same here. My main WAP is still a WRT54GL running Tomato SpeedMod. I even overclocked it pretty heavily several years ago, and after using some thermal adhesive to stick a heatsink to it, it’s been rock solid reliable.

    1. I know that you didn’t mean to say “literally”, but I am assuming you have quite a lot of them. So, why not make a huge mesh network? Give some to your friends and use directional antennas to extend the network.

      1. I did! But we upgraded to radios with better receive sensitivity to get better throughput. Which is why I now have a heap of WRTs.
        Check out the Johannesburg Area Wireless User Group (Jawug), its the network I started in 2000.

  3. There is no need for a voltage regulator because it can be powered directly from 5V.

    The WRT54G is powered by the AC1501-03 DC/DC step down regulator which takes an input between 4.75-40V (*) and generates the 3.3V required for all it’s circuits. This little feature allowed it to work perfectly with passive PoE even with very long cables.

    Check some measurments I did back in the day: http://kioan.users.uth.gr/wireless/wrt54g/supply.html

    * The maximum input voltage is specified by the input capacitors, so it should not exceed 20V unless you replace them.

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