Gyrators: The Fifth Element

July 6, 2017 by 32 Comments

A few years ago, there was a stir about a new fundamental component called a memristor. That wasn’t the first time a new component type was theorized though. In 1948 [Bernard Tellegen] postulated the gyrator. While you can’t buy one as a component, you can build one using other components. In fact, they are very necessary for some types of design. Put simply, a gyrator is a two-terminal device that inverts the current-voltage characteristic of an electrical component. Therefore, you can use a gyrator to convert a capacitor into an inductor or vice versa.

Keep in mind, the conversion is simply the electrical properties. Normally, current leads voltage in a capacitor and lags it in an inductor, and that’s what a gyrator changes. If you use a gyrator and a capacitor to make a virtual inductor, that inductor won’t magnetically couple to another inductor, real or simulated. There’s no magnetic field to do so. You also don’t get big voltage spikes caused by back EMF, which depending on your application could be a plus or a minus. But if you need an ungainly inductor in a circuit for its phase response, a gyrator may be just the ticket.

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Hacking Into…. A Wind Farm?

July 6, 2017 by 21 Comments

Pick a lock, plug in a WiFi-enabled Raspberry Pi and that’s nearly all there is to it.

There’s more than that of course, but the wind farms that [Jason Staggs] and his fellow researchers at the University of Tulsa had permission to access were — alarmingly — devoid of security measures beyond a padlock or tumbler lock on the turbines’ server closet. Being that wind farms are generally  in open fields away from watchful eyes, there is little indeed to deter a would-be attacker.

[Staggs] notes that a savvy intruder has the potential to shut down or cause considerable — and expensive — damage to entire farms without alerting their operators, usually needing access to only one turbine to do so. Once they’d entered the turbine’s innards, the team made good on their penetration test by plugging their Pi into the turbine’s programmable automation controller and circumventing the modest network security.

The team are presenting their findings from the five farms they accessed at the Black Hat security conference — manufacturers, company names, locations and etc. withheld for obvious reasons. One hopes that security measures are stepped up in the near future if wind power is to become an integral part of the power grid.

All this talk of hacking and wind reminds us of our favourite wind-powered wanderer: the Strandbeest!

[via WIRED]

Stalk Your Cats With A Browser-Controlled Robot

July 6, 2017 by 9 Comments

A good robot is always welcome around here at Hackaday, and Hackaday.io user [igorfonseca83]’browser-controlled ‘bot s is no exception. Felines beware.

[igorfonseca83] — building on another project he’s involved in — used simple materials for the robot itself, but you could use just about anything. His goal for this build was to maximize accessibility in terms of components and construction using common tools.

An Arduino Uno gets two D/C motors a-driving using an H-bridge circuit — granting independent control the wheels — an ESP8266 enabling WiFi access, with power provided by a simple 5V USB power bank. [igorfonseca83] is using an Android smartphone to transmit audio and video data; though this was mostly for convenience on his part, a Raspberry Pi and camera module combo as another great option!

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Fixing Bugs In Ancient BASIC Games

July 5, 2017 by 39 Comments

Before everyone learned programming on Stack Exchange, things were much different. Computer magazines had BASIC programs in them, which readers would type out, line by line, and hit RUN. In theory, this is a terrible way to learn programming; it’s simply rote recitation without any insight into what the code is actually doing. Of course, copying and pasting from Stack Exchange is exactly the same thing, so maybe these magazines were ahead of the curve.

[0xA000] recently came across one of his old computer magazines containing the type-in listing for Blindganger, a game where you wander a maze blindly. When [0xA000] typed this game into his C64 back in 1988, the game didn’t work. Thirty years later, he decided to give it another go and ended up fixing bugs in an old computer game.

When [0xA000] typed this game into his computer back in 1988, the map just didn’t work, and the final screen revealed a maze where the walls were where they shouldn’t be. A quick Google turned up a disk image of the same game that had the same problem. This bug was obviously in the section of code that draws the map at the end of the game, so [0xA000] started looking there. The offending typo in the code was an $F4 instead of an $F5, or 244 instead of 255. This shifted the colors of the map by 11 positions, meaning the locations marked as visited in the final screen were wrong. Whether this bug cropped up in development or was just a simple typo when typesetting the magazine doesn’t really matter now; after 29 years, this bug is fixed.

How Do They Synchronize Power Stations With The Grid?

July 5, 2017 by 58 Comments

There are probably times in every Hackaday reader’s life at which you see something and realise that the technology behind it is something you have always taken for granted but have never considered quite how it works. Where this is being written there was such a moment at the weekend, an acquaintance on an amateur radio field day posted a picture of three portable gas-powered alternators connected together and running in synchronization. In this case the alternators in question were fancy new ones with automatic electronic synchronization built-in, but it left the question: how do they do that? How do they connect a new power station to the grid, and bring it into synchronization with the line? There followed a casual web search, which in turn led to the video below the break of a bench-top demonstration.

If two AC sources are to be connected together to form a grid, they must match each other exactly in frequency, phase, and voltage. To not do so would be to risk excessive currents between the sources, which could damage them and the grid infrastructure. The video below from [BTCInstrumentation] demonstrates in the simplest form how the frequencies of two alternators can be matched, by measuring the frequency difference between them and adjusting their speed and thus frequency until they can be connected. In the video he uses neon bulbs which flash at the difference frequency between the two alternators, and demonstrates adjusting the speed of one until the bulbs are extinguished. The two alternators can then be connected, and will then act together to keep themselves in synchronization. There are further videos in which he shows us the same process using a strobe light, then demonstrates the alternators keeping themselves synchronized, and phase deviation between them.

Of course, utility employees probably do not spend their time gazing at flashing neon bulbs to sync their power stations. The same measurements are not performed by eye but by electromechanical or electronic systems with automatic control of the contactors, just as they are in the fancy electronic alternator mentioned earlier. But most of us have probably never had to think about synchronizing a set of alternators, so to see it demonstrated in such a simple manner should fill a knowledge gap even if it’s one only of idle curiosity.

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Hackaday Prize Entry: An Internet Doorbell

July 5, 2017 by 29 Comments

The Internet of Things will kill us all and is the worst idea anyone has ever had. However, just because something could be labeled an ‘Internet of Things thing’ doesn’t mean it’s a bad idea. The Hackaday Prize’s Internet of Useful Things challenge was all about finding the Internet of Useful things, and one of these projects is so simple yet so elegant, we’re surprised no one has thought of it yet.

[David]’s entry to the Hackaday Prize is effectively an Internet of Things doorbell. You might think an IoT doorbell would just consist of a device sending push notifications to your phone. That’s part of the project, but it gets so much better.

The brilliant part of this build boils down to a simple relay. On command, [David] can turn his doorbell off. This means no ringing doorbell interrupting meals or naps. By sending a command to the ESP32 in this little device, [David] can enable or disable his doorbell. Of course, this doorbell also sends push notifications to his phone, so if the UPS guy throws a package at his front door and manages to hit the doorbell, [David] will still hear it even if he’s upstairs, in the garage, or in the backyard.

This is the simplest and most brilliant Internet of Things device ever created. It solves an obvious problem with surprisingly little hardware. The only data this device collects is the state of a doorbell, and even if this device was completely hacked by balaclava-wearing hackers, they still can’t F5 the doorbell. This is the best the Internet of Things has to offer, and we’re proud to have the Internet of Doorbells make it to the finals of the Hackaday Prize.

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Camera Slide Pans And Tilts Camera Mechanically

July 5, 2017 by 22 Comments

A camera slider is a popular and simple project — just a linear slide, a stepper, and some sort of controller. Adding tilt and pan axes ups the complexity until you’ve got three motors, a controller, and probably a pretty beefy battery pack to run everything. Why not simplify with an entirely mechanical pan-tilt camera slider and leave all that heavy stuff at home?

There’s more than one way to program motion control, and [Enza3D]’s design uses adjustable rails to move the gimballed pan-tilt head through two axes of motion. One rail adjusts vertically to control tilt, while the other adjusts in and out relative to the slider to control pan. Arms ride on each rail and connect to the gimbals to swivel the camera in both dimensions while it travels down the manually cranked slide. It’s pretty clever and results in some clean, dynamic shots as in the video below.

Our quibble is that the “program” is only linear since the control rails are straight lengths of aluminum extrusion; seems to us that some sort of flexible control rails might make for more interesting shots. [Enza3D] has amply documented the build and is looking for feedback, so comment away. And if you don’t have a 3D printer to make the parts, wood works for a slider too.

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