Build an In Line Network Bandwidth Monitor

[Kurt] likes to know what’s going on with his network. He already uses bandwidth checking software on his DD-WRT capable router, but he wanted a second opinion. So he built his own network monitor. [Kurt] started by building a passive Ethernet tap. He then needed a network interface chip that would serve his purposes. The common Wiznet chips used with Arduinos didn’t allow enough manipulation of raw packet data, so he switched to a Microchip ENC624J600 (PDF). The Microchip controller allowed him to count the bytes in the raw Ethernet packets.

With the Ethernet interface complete, [Kurt] turned his attention to a microcontroller to run the show. He started with an Arduino, but the lack of debugging quickly sent him to an Atmega128 in Atmel Studio. After getting the basic circuit working, [Kurt] switched over to a PIC24F chip. With data finally coming out of the circuit, he was able to tell that his original back-of-the-napkin calculations for bandwidth were wrong. [Kurt] created a PCB to hold the microcontroller, then wrote a Python program to plot the data output from his circuit. The bandwidth plot matched up well with the plot from DD-WRT. Now he just needs a giant LED matrix to show off his current network stats!

An overkill network adapter for retrocomputers


If you want to get an old Apple, Commodore 64, Amiga, or any other retrocomputer up on the Internet, this is for you. [Stian] had an Amiga 500 lying around and wanted to put it on a network. The A500 isn’t expandable, so he needed to look at some sort of adapter to put it on a network. The solution came to him in the form of a Raspberry Pi, a null modem cable, and a few bits of software.

To connect his Amiga to his network, [Stian] made a small serial converter board for his Raspi that breaks out the Tx and Rx pins on the Pi to a 9-pin serial port. With the physical connection to the Pi made, the only thing left to do was to get some software for the Amiga, namely AmiTCP and PPP. It’s not exactly a fast network connection, but this build allows [Stian] to connect to WiFi networks with ancient hardware.

One interesting aspect of [Stian]’s build is the fact it’s completely transferable to other retrocomputers – everything from old S-100 bus computers to classic macs, apples, and pretty much anything else with a serial port that supports PPP. Even with the expense of a Raspberry Pi, it’s much cheaper than absurdly expensive second-hand SCSI to Ethernet controllers and other tomfoolery.

AVR Minecraft server lets you toggle pins from the virtual world

Wanting to test his skills by building a webserver [Cnlohr] decided to also code a Minecraft server which allows him to toggle pins from inside the game. The rows of switches seen above give him direct access to the direction register and I/O pins of one port of the ATmega328.

The server hardware is shown in the image above. It’s hard to tell just from that image, but it’s actually a glass substrate which is [Cnlohr’s] specialty. He uses an ENC424J600 to handle the networking side of things. This chip costs almost twice as much as the microcontroller next to it. But even in single quantities the BOM came in at under $20 for the entire build.

In the video after the break [Cnlohr] and a friend demonstrate the ability for multiple users to log into the Minecraft world. The simulation is fairly bare-bones, but the ability to affect hardware from the game world is more exciting than just pushing 1s and 0s through some twisted pairs.

Continue reading “AVR Minecraft server lets you toggle pins from the virtual world”

Vodafone USB 3G modem driver from mbed

Wow, that’s a really simple hardware setup to supply your device with a 3G Internet connection. Better yet, the software side is just as simple thanks to the Vodafone USB Modem library for mbed. It will work for any of the cell data plans offered by Vodafone. The only problem you may have is not living in one of the 30 countries serviced by the telco.

The dongle seen at the right is sold by Vodafone and is meant to be used for Internet data, so you won’t be doing anything that might get your SIM banned. Connecting to the network is a one-liner thanks to the previously mentioned library. From there, gets and posts can be done with your favorite package. The  Hello World example uses HTTPClient. And since the mbed is simply an ARM platform it shouldn’t be hard to use the library with the ARM chip of your choice.

Keep others from snooping in your digital life

In our digital age prying eyes are everywhere. The sad thing is that they may even belong to your own government. But no matter who it is, there are some things you can do to keep your private digital devices and content as secure as possible.

The link above goes to [Jerry Whiting’s] discussion on the topic. He’s certainly an interesting speaker, but make sure you’re using headphones at work as the language can be a bit sultry once in a while. He aims the lesson at the Occupy movement, but it’s a fun listen for any conspiracy theorist out there. The topics run the gamut, starting with the specter of physical access, then moving on to protecting your network through traffic analysis and using key pairs. This Security 101 segment comes in two parts (the first one is embedded after the break), each a bit more than thirty minutes. He’s planning to post a second lesson covering hashes and encryption. Continue reading “Keep others from snooping in your digital life”

Sniff Ethernet with a throwing star

[Michael Ossmann] came up with a nifty little device that arranges RJ45 plugs into a plus shape for the intent of sniffing Ethernet packets, and named it the “Throwing Star LAN Tap”. While the original design worked fine it does suffer some limitations such as being limited to 10/100 base networks, and one way only. This new version of the “Throwing Star LAN Tap” fixes those and adds some much needed convenience.

Gone are the male plugs, which requires couplers and are prone to break, and fiddly splices in favor of a throwing star shaped pcb, and female sockets. 1000 base networks are supported, but due to the workings of 1000 base and wanting to keep the device passive, capacitors are added to filter out the signal and force the network to drop down to 100 base. Sure, it may be an ugly hack, but it’s an ugly hack that fits in your pocket.

Network packet sniffing with Linux

Here’s a chance to learn a little bit about network security. This article walks us through some of the core concepts of network manipulation and packet sniffing using Linux tools. [Joey Bernard] discusses the uses for packages like tcpdump, p0f, and dsniff. They are capable of recording all network traffic coming through your computer’s connection, seeking out machines installed on the network, and listening to traffic for a specific machine. This isn’t going to give you a step-by-step for cracking modern networks. It will provide some insight on what is going on with your network and you should be able to purpose these tools to check that you’ve got adequate security measures in place.