Amazon Alexa, Google Home, and just about every electronic device manufacturer are jumping on the bandwagon of connected devices. They promise us the ability to turn on our toaster from another room, unlock our doors just by shouting at them from outside, and change the channel on our TV through perfectly enunciating a sentence instead of mashing the buttons on our remotes like chumps. And yet, despite all this new-fangled finger-less control, there is an unanswered question: does this technology save us energy in the long run?
For years we’ve been hearing about vampire power and all the devices in our home that sit in standby, waiting for their masters to turn them on, quietly burning power to listen for that signal to wake. Fortunately the One Watt Initiative and general awareness and design for energy savings has cut out a lot of this phantom load. So how does the smart home, which essentially adds a bunch of connected vampires to our base load, end up saving money in the long run? And is it better than other alternatives or just good habits? I put these questions to the test with today’s smart power strips and controllable outlets.
[Nate] has made snowboarding cool with his Bluetooth connected board. Using 202 WS2812 LEDs carefully wrapped around the edge of the board and sealed with a conformal coating, it’s bright and waterproof. It’s controlled with an Arduino Nano and a Bluetooth classic board, as well as a large swappable USB battery bank; he can get roughly four hours of life at full brightness on his toy.
Where it gets even cooler is with a six-axis gyro connected to the Nano, which tracks the board movement, and the lights respond accordingly, creating cool patterns based on his speed, angles, and other factors. The app used to control this intense ice-rider is a custom app written using MIT App Inventor, which has the ability to work with Bluetooth classic as well as BLE. This came in handy when he made the 100-LED skateboard, which is based on a Feather with BLE and a large LiPo battery. The challenging part with the skateboard was making the enclosure rugged enough (yet 3D printed) to withstand terrain that is a lot less fluffy than snow.
You’ve just finished your project. Well, not finished, but it works and you’ve solved all the problems worth solving, and you have a thing that works for you. Then you think about sharing your creation with the world. “This is cool” you think. “Other people might think it’s cool, too.” So you have to take pictures and video, and you wish you had documented some more of the assembly steps, and you have to do a writeup, and comment your code, and create a repository for it, maybe think about licensing. All of a sudden, the actual project was only the beginning, and now you’re stressing out about all the other things involved in telling other people about your project, because you know from past experience that there are a lot of haters out there who are going to tear it down unless it’s perfect, or even if it is, and even if people like it they are going to ask you for help or to make one for them, and now it’s 7 years later and people are STILL asking you for the source code for some quick little thing you did and threw up on YouTube when you were just out of college, and of course it won’t work anymore because that was on Windows XP when people still used Java.
Take a deep breath. We’ve all been there. This is an article about finding a good solution to sharing your work without dealing with the hassle. If you read the previous paragraph and finished with a heart rate twice what you started, you know the problem. You just want to share something with the world, but you don’t want to support that project for the rest of your life; you want to move on to new and better and more interesting projects. Here are some tips.
Arduino 101 is getting an LED to flash. From there you have a world of options for control, from MOSFETs to relays, solenoids and motors, all kinds of outputs. Here, we’re going to take a quick look at some inputs. While working on a recent project, I realized the variety of options in sensing something as simple as whether a light is on or off. This is a fundamental task for any system that reacts to the world; maybe a sensor that detects when the washer has finished and sends a text message, or an automated chicken coop that opens and closes with the sun, or a beam break that notifies when a sister has entered your sacred space. These are some of the tools you might use to sense light around you.
Cloudflare announced recently that they are seeing an increase in amplification attacks using memcached servers, and that this exploit has the potential to be a big problem because memcached is capable of amplifying an attack significantly. This takes DDoS attacks to a new level, but the good news is that the problem is confined to a few thousand misconfigured servers, and the solution is to put the servers behind a tighter firewall and to disable UDP. What’s interesting is how the fundamental workings of the Internet are exploited to create and direct a massive amount of traffic.
We start with a botnet. This is when a bunch of Internet-connected devices are compromised and controlled by a malicious user. This could be a set of specific brand of web camera or printer or computer with unsecured firmware. Once the device is compromised, the malicious user can control the botnet and have it execute code. This code could mine cryptocurrency, upload sensitive data, or create a lot of web traffic directed at a particular server, flooding it with requests and creating a distributed denial of service (DDoS) attack that takes down the server. Since the server can’t distinguish regular traffic from malicious traffic, it can’t filter it out and becomes unresponsive.
This DDoS attack is limited to the size of the botnet’s bandwidth, though. If all the web cameras in the botnet are pounding a server as fast as they can, the botnet has reached its max. The next trick is called an amplification attack, and it exploits UDP. UDP (as opposed to TCP) is like the early post office; you send mail and hope it gets there, and if it doesn’t then oh well. There’s no handshaking between communicating computers. When a device sends a UDP packet to a server, it includes the return address so that the server can send the response back. If the device sends a carefully crafted fake request with a different return address, then the server will send the response to that spoofed return address.
So if the web camera sends a request to Server A and the response is sent to Server B, then Server A is unintentionally attacking Server B. If the request is the same size as the response, then there’s no benefit to this attack. If the request is smaller than the response, and Server A sends Server B a bunch of unrequested data for every request from the camera, then you have a successful amplification attack. In the case of memcached, traffic can be amplified by more than 50,000 times, meaning that a small botnet can have a huge effect.
Memcached is a memory caching system whose primary use is to help large websites by caching data that would otherwise be stored in a database or API, so it really shouldn’t be publicly accessible anyway. And the solution is to turn off public-facing memcached over UDP, but the larger solution is to think about what things you are making available to the Internet, and how they can be used maliciously.
Look on the back of your laptop charger and you’ll find a mess of symbols and numbers. We’d bet you’ve looked at them before and gleaned little or no understanding from what they’re telling you.
These symbols are as complicated as the label on the tag of your shirt that have never taught you anything about doing laundry. They’re the marks of standardization and bureaucracy, and dozens of countries basking in the glow of money made from issuing certificates.
The switching power supply is the foundation of many household electronics — obviously not just laptops — and thus they’re a necessity worldwide. If you can make a power supply that’s certified in most countries, your market is enormous and you only have to make a single device, possibly with an interchangeable AC cord for different plug types. And of course, symbols that have meaning in just about any jurisdiction.
In short, these symbols tell you everything important about your power supply. Here’s what they mean.
It takes a surprising amount of planning and work if you want something to look old. [vemeT5ak] wanted the Echo Dot sitting on his desk to fit a different aesthetic motivated by a 1940s Canadian radio. Armed with Solidworks, a Tormach CNC, and some woodworking tools at Sector67 hackerspace, he built a retro-futuristic case for the Amazon Alexa-enabled gadget. Future and past meet thanks to the design and material appearance of the metal grille and base molding wrapping the wood radio case. The finishing touch is of course the ring of blue light which still shines through from the Echo itself.
It took about 15 hours of modeling, scaling, and tweaking in Solidworks with an interesting design specification in mind: single-bit operation. This single-bit is not in the electrical sense, but refers to the CNC milling operation. All pieces are cut with a 1/4″ end mill, without any tool changes. Metal pieces were milled from 6061 aluminum and the hickory case (with burgundy stain) was mostly cut on a table saw, but the holes were CNC machined.
What looks like an otherwise perfect build has a single flaw that eats up [vemeT5ak]’s soul; the Echo Dot has a draft angle that wasn’t considered during modeling, and the hole is ever so slightly too wide, meaning it didn’t press fit perfectly flush. Fortunately it’s not noticeable behind the metal grill, and unless you knew (please help keep his dirty little secret), you would think everything turned out perfectly.
It turns out building a case for the Echo Dot is challenging for a few reasons; the rubbery material on the bottom doesn’t allow anything to stick to it, and the sides are smooth and featureless with a taper that makes it difficult to lock it in. Many cases resort to clipping over the top to hold it in place. Others install it into a fish or a furby.