About a decade ago, [Mansour] learned of the Linksys WRT54G, a wireless router that’s been shoved into just about every project under the sun. After learning of this device’s power, he decided a firmware upgrade was in order. Unfortunately, he accidentally bricked this router and left it sitting on a shelf for a few years.
Idle devices are the devil’s playthings, and when [Mansour] discovered a Samsung hard drive with a an SDRAM that was compatible with the WRT54G, he decided he would have a go at repairing this ancient router. There was only one problem: the most popular utility for programming the router through the JTAG header required a PC parallel port.
No problem, then, as [Mansour] had a Raspberry Pi on hand. The parallel port utility bit-banged the new firmware over to the router, something the GPIO port on the Pi could do in spades. By adding Pi support to the debricking utility, [Mansour] had a functional WRT54G with just a little bit of patience and a few wires connecting the GPIO and JTAG header.
The guys over at Section9 Hackerspace in Springfield, Missouri just finished building this treaded robot. Despite the juxtaposition of the cat, it really doesn’t defend anything. The project is a reconnaissance robot controlled over the network with video feedback.
The team started off with some lofty goals. They wanted to the robot to be able to climb stairs and to feature a detachable flying portion in order to get a better look at hard to reach places. Cost and complexity are cited as the reasons they ditched the idea of the flyer. The rest of the features came out much as planned. The motor controller for the treads is connected to an Arduino. This uses an Ethernet shield to connect to the WRT54G router which is also coming along for the ride. This seems a bit over-powered but it makes it easy to connect the webcam on the front (also via Ethernet).
On the software side they wrote an Android app. It controls the movement of the robot, as well as that of the camera. Of course you need to see where you’re going so they went the extra mile to include video from the webcam. Check out their show-and-tell video after the break.
Continue reading “Tank router defends your pets?”
[John Graham-Cumming] was all set to start a new project based on the Raspberry Pi. Well, that was until shipment was delayed due to manufacturing issues. Not to fret, he transitioned over to a router board which displays the arrival countdown for mass transit bus service.
He based the build on a web page the Transport for London provided. You can load it up and see if your bus is running on time or not. There’s no published API, but by studying the source code from the site [John] was able to figure out how the JSON commands were formatted.
The next step is building a standalone device to pull the data and display it. The board seen above is from a Linksys WRT54GL router. This longtime favorite has a serial port header which can be driven from the Linux kernel. He wired up a jack on the router’s case, and uses an extension cable to get from it to the 7-segment displays mounted in a model of the bus. Since there’s four digits the display can tell you minutes until the arrival of two different buses.
[Thanks Pseudo Lobster]
The wooden frame seen above hosts a parabolic reflector making up one side of a wireless network link. This is a Fab Lab project called FabFi which uses common networking hardware to setup long-distance wireless Ethernet connections. It’s a bit hard to tell in the image above, but the reflector focuses radio waves on the antennae of a router we’re quite familiar with, the Linksys WRT54G. It’s held upside-down in an enclosure meant to protect it from the elements. The node above manages to complete a connection spanning 2.41 miles!
One of the core values of the project is to develop hardware that is easy to build with limited resources, then to make that knowledge freely available. Anyone who has the ability to download and print out the 2D design file can build a reflector for themselves. As we’ve seen in other projects, paper stencils and hand tools can handle this job with no need for a laser-cutter (which was used for the prototype). WRT54G routers are inexpensive and the project uses the open source firmware OpenWRT. They can be run from 12VDC power which means a car battery works when mains power is not an option. The system has been running in Afghanistan for two years and hardware failure is still in the low single-digits.
The Linksys router seen about is a WRT54G version 1. It famously runs Linux and was the source of much hacking back in the heyday, leading to popular alternative firmware packages such as DD-WRT and Tomato. But the company went away from a Linux-based firmware starting with version 8 of the hardware. Now they are using a proprietary Real Time Operating System called VxWorks.
[Craig] recently put together a reverse engineering guide for WRT54Gv8 and newer routers. His approach is purely firmware based since he doesn’t actually own a router that runs VxWorks. A bit of poking around in the hex dump lets him identify different parts of the files, leading to an ELF header that really starts to unlock the secrets within. From there he carries out a rather lengthy process of accurately disassembling the code into something that makes sense. The tool of choice used for this is IDA Pro diassembler and debugger. We weren’t previously familiar with it, but having seen what it can do we’re quite impressed.
[Image via Wikimedia Commons]
[Chris Kantarjiev] is an amateur radio enthusiast (call sign K6DBG) and does a lot with the APRS. We think his build, turning a WRT54gl router into an APRS gateway will be very useful for the APRS tracker builds we’ve been covering.
Setting up an Internet Gateway, or igate, on APRS usually requires a ‘real’ computer. [Chris] didn’t like that idea, so he took aprs4r, igate software for embedded devices, and pruned it down to fit on the 4MB of flash and 16MB of RAM in the WRT.
The actual APRS hardware is connected though headers soldered onto the WRT54gl’s board which go to a small PIC-Based TNC. [Chris] argues that the APRS ‘backbone’ is great, but there aren’t enough nodes on the network for full coverage. We thing this would be a great way to put cheap hardware out in the wild to cover those gaps in the APRS network.
Check out the video for a rundown of the modded WRT54g after the break. If you’re interested amateur radio, Field Day is coming up in just 2 weeks. Find a local club and check out what’s possible with amateur radio.
Continue reading “Turning a router into an APRS gateway”
Meet TIPI, the Telepresence Interface by Pendulum Inversion. TIPI is something of a surrogate, giving physical presence to telecommuters by balancing an LCD screen and camera atop its six foot frame. The user has full control of the robot’s movement, with their own camera image shown on the display so that others interacting with the bot will with whom they are conversing.
A pair of 12.5″ wheels connec to DC motors via a gear box with a 37:1 ratio. These specs are necessary to recover from a sudden 20 degree loss of equilibrium, quite impressive for a bot of this stature. An Orangutan SVP board monitors a two-axis accelerometer and a gyroscope for accurate positioning data. This board automatically keeps balance, while taking user commands from a second control, a Beagle Board. The Beagle Board handles the communications, including sending and receiving the video signals, and delivering incoming position control data to the Orangutan. Separating the two systems guards against a screen-shattering fall by making sure the hardware likely to face slow-down or lockup is physically separate from that responsible for balance.
Check out the video clip after the brake to see some balancing goodness. It shouldn’t be hard to build your own version for much less than the $15k price tag enjoyed by some commercial versions.
Continue reading “Your robot stand-in has arrived”