Power Over Ethernet Splitter Improves Negotiating Skills

August 24, 2018 by Ben James 18 Comments

Implementing PoE is made interesting by the fact that not every Ethernet device wants power; if you start dumping power onto any device that’s connected, you’re going to break things. The IEEE 802.3af standard states that the device which can source power should detect the presence of the device receiving power, before negotiating the power level. Only once this process is complete can the power sourcing device give its full supply. Of course, this requires the burden of smarts, meaning that there are many cheap devices available which simply send power regardless of what’s plugged in (passive PoE).

[Jason Gin] has taken an old, cheap passive PoE splitter and upgraded it to be 802.3af compatible (an active device). The splitter was designed to be paired with a passive injector and therefore did not work with Jason’s active 802.3at infrastructure.

The brain of the upgrade is a TI TPS2378 Powered Device controller, which does the power negotiation. It sits on one of two new boards, with a rudimentary heatsink provided by some solar cell tab wire. The second board comprises the power interface, and consists of dual Schottky bridges as well a 58-volt TVS diode to deal with any voltage spikes due to cable inductance. The Ethernet transformer shown in the diagram above was salvaged from a dead Macbook and, after some enamel scraping and fiddly soldering, it was fit for purpose. For a deeper dive on Ethernet transformers and their hacked capabilities, [Jenny List] wrote a piece specifically focusing on Raspberry Pi hardware.

[Jason]’s modifications were able to fit in the original box, and the device successfully integrated with his 802.3at setup. We love [Jason]’s work and have previously written about his eMMC adventures, repairing windows tablets and explaining the intricacies of SD card interfacing.

Measuring Web Latency In The Browser

July 21, 2018 by Tom Nardi 8 Comments

We’ll go out on a limb and assume that anyone reading these words is probably familiar with the classic ping command. Depending on which operating system you worship the options might be slightly different, but every variation of this simple tool does the same thing: send an ICMP echo request and wait for a response. How long it takes to get a response from the target, if it gets one at all, is shown to the user. This if often the very first step to diagnosing network connectivity issues; if this doesn’t work, there’s an excellent chance the line is dead.

But in the modern web-centric view of networking, ping might not give us the whole picture. But nature it doesn’t take into account things like DNS lookups, and it certainly doesn’t help you determine what (if any) services the target has available to you. Accordingly, [Liu Zhiyong] has come up with a tool he calls “pingms”, which allows you to check web server latency right from your browser.

Rather than relying on ICMP, pingms performs a more realistic test. It takes the list of targets from the file “targets.js” and connects to each one over HTTP. How does it work? The code [Liu] has come up with will take each target domain name, append a random number to create a gibberish filename, and then calculate how long it takes to get a response when trying to download the file. Obviously it’s going to be getting a 404 response from the web server, but the important thing is simply that it gets the response.

With this data, [Liu] has come up with a simplistic but very slick interface which shows the user the collected data with easy to understand color-coded graphs. As interesting as it is to see how long it takes your favorite web sites or service providers to wake up and start talking, watching the colored bars hop up and down the list to sort themselves is easily our favorite part of pingms.

[Liu] has released pingms under the GPLv3 license, so if you’re looking to utilize the software for your own purposes you just need to provide a list of test targets. If you need to perform low-level diagnostics, check out this handy network tester you can build for cheap.

Tiny Websites Have No Server

July 7, 2018 by Al Williams 49 Comments

A big trend in web services right now is the so-called serverless computing, such as Amazon’s Lambda service. The idea is you don’t have a dedicated server waiting for requests for a specific purpose. Instead, you have one server (such as Amazon’s) listening for lots of requests and on demand, you spin up an environment to process that request. Conceptually, it lets you run a bit of Javascript or some other language “in the cloud” with no dedicated server. https://itty.bitty.site takes this one step farther. The site creates self-contained websites where the content is encoded in the URL itself.

Probably the best example is to simply go to the site and click on “About itty bitty.” That page is itself encoded in its own URL. If you then click on the App link, you’ll see a calculator, showing that this isn’t just for snippets of text. While this does depend on the itty.bitty.site web host to provide the decoding framework, the decoding is done totally in your browser and the code is open source. What that means is you could host it on your own server, if you wanted to.

At first, this seems like a novelty until you start thinking about it. A small computer with an Internet connection could easily formulate these URLs to create web pages. A bigger computer could even host the itty.bitty server. Then there’s the privacy issue. At first, we were thinking that a page like this would be hard to censor since there is no centralized server with the content. But you still need the decoding framework. However, that wouldn’t stop a sophisticated user from “redirecting” to another — maybe private — decoding website and reading the page regardless of anyone’s disapproval of the content.

Continue reading “Tiny Websites Have No Server” →

Neat Odroid & GlusterFS Build Stashes Data, Sips Power

June 14, 2018 by Richard Baguley 29 Comments

Most of us accumulate stuff, like drawers full of old cables and hard drives full of data. Reddit user [BaxterPad] doesn’t worry about such things though, as he built an impressive Network Attached Storage (NAS) system that can hold over 200TB of data. That’s impressive enough, but the real artistry is in how he did this. He built this system using ODroid HC2 single board computers running GlusterFS, combining great redundancy with low power usage.

Continue reading “Neat Odroid & GlusterFS Build Stashes Data, Sips Power” →

A Home Network, Security System, And A Hidden Room Behind A Bookcase

May 6, 2018 by James Hobson 33 Comments

Ok, now this is something special. This is a home network and security system that would make just about anyone stop, and with jaw hanging agape, stare, impressed at the “several months of effort” it took [timekillerjay] to install their dream setup. Just. Wow.

Want a brief rundown of the diverse skill set needed to pull this off? Networking, home security, home automation, woodworking, running two thousand feet(!) of cat 6a cable, a fair hand at drywall work for the dozens upon dozens of patches, painting, staining, and — while not a skill, but is definitely necessary — an amazingly patient family.

Ten POE security cameras monitor the premises with audio recording, infrared, and motion detection capabilities. This is on top of magnetic sensors for five doors, and eleven windows that feed back to an ELK M1-Gold security system which effortlessly coordinates with an Insteon ISY994i smart home hub; this allows for automatic events — such as turning on lights after dark when a door is opened — to occur as [timekillerjay]’s family moves about their home. The ELK also allows [timekillerjay] to control other things around the house — namely the sprinkler system — via relays. [timekillerjay] says he lost track of how many smart switches are scattered throughout his home, but there are definitely 39 network drops that service the premises.

All of the crucial components are hidden in his office, behind a custom bookshelf. Building it required a few clever tricks to disguise the bookshelf for the secret door that it is, as well as selecting components with attention to how much noise they generate — what’s the point of a hidden security system if it sounds like a bunch of industrial fans?

An uninterruptible power supply will keep the entire system running for about 45 minutes if there is a power outage, with the cameras recording and system logging everything all the while. Not trusting the entrance to his vault to something from Batman, he’s also fitted the bookshelf with a 600lb magnetic lock that engages when the system is armed and the door already closed. A second UPS will keep the door secured for 6+ hours if the house loses power. Needless to say, we think this house is well secured.

[Via /r/DIY]

Building The Perfect Home Router

April 12, 2018 by Tom Nardi 43 Comments

When a favorite piece of hardware dies, it’s fairly common to experience a bit of dread. The thought that now you’ll have to go through the process of getting a replacement for the device can be very troubling, and is fraught with difficult questions. Is the hardware still available? Has it been made obsolete by something else in the time you’ve had it? But while it can be a hassle, there’s no question you can come out the other side better than you went in. Sometimes it takes the passing of an old piece of gear for you to really embrace what’s possible with the latest and greatest.

That’s exactly what happened to [Tyler Langlois]. When his trusty home router finally gave up the ghost, he was left with a couple of options. He could get another consumer router, upgrade to a enterprise-level model, or take the road less traveled and build his own router to his exacting specifications. Since you’re reading about it on Hackday, we’ll give you one guess as to which door he went through.

The blog post [Tyler] has written up about the saga of building his own router is an incredible resource for anyone who might be thinking of taking the plunge into DIY networking. From selecting the proper hardware to the nuances of getting all of the software packages installed, this is an absolute treasure trove. At the beginning of the post he mentions that the post shouldn’t be considered a comprehensive guide, but considering we’ve seen commercial hardware that wasn’t documented this well, we’d have to respectfully disagree on that point.

Some elements of his homespun may come as something of a surprise. For one, [Tyler] bucked the hive mentality and determined the Raspberry Pi simply wasn’t up to the task due (at least in part) to the single 100 Mbps network interface. He ended up going with an ESPRESSObin, a relatively niche Linux SBC that features an onboard gigabit switch in addition to a fairly hefty spec sheet. He also decided to forgo WiFi entirely, and leave the intricacies of wireless networking to a standalone access point from Ubiquity.

A router is often overlooked as just another piece of consumer kit sitting around the house, but it’s actually an excellent place to flex your creative and technical muscle. From adding a remote display to converting it into a mobile battle tank, there’s a lot more you can do with your router than stare at the blinkenlights.

3D Printed Raspberry Pi NAS With Dual Drive Bays

March 21, 2018 by Tom Nardi 37 Comments

While it might not pack the computational punch you’d usually be looking for in a server platform, you can’t beat how cheap the Raspberry Pi is. As such, it’s at the heart of many a home LAN, serving up files as a network attached storage (NAS) device. But the biggest problem with using the Pi in a NAS is that it doesn’t have any onboard hard drive interface, forcing you to use USB. Not only is this much slower, but doesn’t leave you a lot of options for cleanly hooking up your drives.

This 3D printable NAS enclosure designed by [Paul-Louis Ageneau] helps address the issue by integrating two drive bays which can accommodate 2.25 inch laptop hard disk drives and their associated IB-AC6033-U3 USB adapters. The drives simply slide into the “rails” designed into the case without the need for additional hardware. There’s even space in the bottom of the case for a USB hub to connect the drives, and a fan on the top of the case to help keep the whole stack cool. It still isn’t perfect, but it’s compact and doesn’t look half bad.

The design is especially impressive as it doesn’t require any supports, an admirable goal to shoot for whenever designing for 3D printing. As an added bonus, the entire case is designed in OpenSCAD and licensed under the GPL v3; making modification easy if you want to tweak it for your specific purposes.

This certainly isn’t the strongest Raspberry Pi enclosure we’ve ever seen, that title would have to go to the ammo case that does double duty as a media streamer, but looks like it would make a great home for that new 3 B+ you’ve got on order.