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Reading the Unreadable SROM: Inside the PSoC4

เสาร์, 03/04/2017 - 22:01

Wow. [Dmitry Grinberg] just broke into the SROM on Cypress’ PSoC 4 chips. The supervisory read-only memory (SROM) in question is a region of proprietary code that runs when the chip starts up, and in privileged mode. It’s exactly the kind of black box that’s a little bit creepy and a horribly useful target for hackers if the black box can be broken open. What’s inside? In the manual it says “The user has no access to read or modify the SROM code.” Nobody outside of Cypress knows. Until now.

This matters because the PSoC 4000 chips are among the cheapest ARM Cortex-M0 parts out there. Consequently they’re inside countless consumer devices. Among [Dmitry]’s other tricks, he’s figured out how to write into the SROM, which opens the door for creating an undetectable rootkit on the chip that runs out of each reset. That’s the scary part.

The cool parts are scattered throughout [Dmitry]’s long and detailed writeup. He also found that the chips that have 8 K of flash actually have 16 K, and access to the rest of the memory is enabled by setting a single bit. This works because flash is written using routines that live in SROM, rather than the usual hardware-level write-to-register-and-wait procedure that we’re accustomed to with other micros. Of course, because it’s all done in software, you can brick the flash too by writing the wrong checksums. [Dmitry] did that twice. Good thing the chips are inexpensive.

The nitty-gritty on the ROP (return oriented programming) tricks that [Dmitry] had to pull, and a good look into the design of the system itself, are all up on [Dmitry]’s blog. We can’t wait to see what other buried treasure he’s going to find as he continues to play around with these chips. And in case you’re wondering what type of mad genius it takes to pull this off, consider that [Dmitry] runs Linux on AVRs, fools nRF24 chips into transmitting Bluetooth LE beacons, and re-writes his own airplane’s GPS.

[Main image is a PSoC4200 dev kit, and [Dmitry] has only been working with the 4000 and 4100 series. Just so you know.]

Filed under: Microcontrollers

WiFi Power Bar!

เสาร์, 03/04/2017 - 19:01

Ever wanted to access a file or run some program on your computer while away from home, but the darned thing is turned off? Finding themselves occasionally working away from home and not wanting to leave their computer on for extended periods, [robotmaker]’s solution was to hack into existence a WiFi-controlled power bar!

Inside the junction box, an eight-channel relay is connected to an ESP8266 module. The module uses MQTT to communicate with Home Assistant and is powered by a partially dismembered USB AC adapter — wrapped in kapon tape for safe-keeping. The entire bar is wired through a 10A fuse, while also using a fire resistant 4-gang electrical box. Once the outlets were wired in, closing it up finished up the power bar.

[robotmaker] controls the outlets via a cheap smartphone — running HADashboard — mounted to a wall with a 3D printed support. Don’t worry — they’ve set up the system to wait for the PCs to power down before cutting power, and the are also configured to boot up when the relay turns on.

The best part — the power bar only cost $25.

[via /r/homeautomation]

Filed under: hardware, home hacks, wireless hacks

This Art Project’s Video is Not a Time-Lapse

เสาร์, 03/04/2017 - 16:01

Artist Pe Lang uses linear polarization filters to create an unusual effect in his piece polarization | nº 1. The piece consists of a large number of discs made from polarizing film that partially overlap each other at the edges. Motors turn these discs slowly, and in the process the overlapping portions go from clear to opaque black and back again.

The disc rotation speed may be low but the individual transitions occur quite abruptly. Seeing a large number of the individual discs transitioning in a chaotic pattern — but at a steady rate — is a strange visual effect. About 30 seconds into the video there is a close up, and you can see for yourself that the motors and discs are all moving at a constant rate. Even so, it’s hard to shake the feeling of that one is watching a time-lapse. See for yourself in the video, embedded below.

Polarizing filters seem to give people ideas, because they are often used in different ways for unusual or clever results. For example, the polarizing filter from a laptop screen was used to create the visuals in this polariscope-like art fixture, and polarized filters were put to work to hide secret messages on LCD screens.

Filed under: misc hacks

Antenna Analyzer is a Lab in a Box

เสาร์, 03/04/2017 - 13:00

There was a time when the measure of a transmitting radio antenna was having it light an incandescent bulb. A step up was a classic SWR/Power meter that showed you forward and reflected power. Over the years, a few other instruments have tried to provide a deeper look into antenna performance. However, the modern champion is the antenna analyzer which is a way of measuring vector impedance.

[Captain Science] did a review of an inexpensive N1201SA analyzer. This device is well under $200 from the usual Chinese sellers. The only thing a bit odd is the frequency range which is 140 MHz to 2700 MHz. For some extra money (about $80 or $100 more) you can drop the low-end frequency to just under 35 MHz.

In addition to the review, you might want to read the manual. The device can measure resistance, reactance, SWR, and S11 (the S parameter for return loss). It also displays the impedance and effective inductance. [Captain Science] thought the interface was easy to use, but he did wish for a numeric keypad.

While you might think this is a great toy for ham radio operators, it would be useful for anyone wanting an antenna in this frequency range. For example, if you are trying to maximize WiFi range or figure out the greatest ever antenna on your drone, this could be for you (as long as you are not on the 5 GHz band).

If this is still too expensive and you want a less flashy solution, you can try an Arduino-based design. There’s plenty of them around.

Filed under: radio hacks, reviews

Powering A Laptop With Supercapacitors

เสาร์, 03/04/2017 - 10:00

What do you do when you find a small horde of supercapacitors? The correct answer is a spectrum of dangerous devices ranging from gauss guns to quarter shrinkers. [Rinoa] had a less destructive idea: she’s replaced the battery in a laptop with a bank of supercapacitors.

The supercaps in question are 2.7 Volt, 500 Farad caps arranged in banks six for a total of about 3 watt-hours in each bank. The laptop used for this experiment is an IBM Thinkpad from around 1998. The stock battery in this laptop is sufficiently less advanced than today’s laptop batteries. Instead of using a microcontroller and SMBus in the battery, the only connections between the battery and laptop are power, ground, and connections for a thermocouple. This is standard for laptops of the mid-90s, and common in low-end laptops of the early 2000s. It also makes hacking these batteries very easy as there’s no associated microprocessors to futz around with.

With all the capacitor banks charged, the laptop works. It should – there isn’t a lot of intelligence in this battery. With one bank of six supercaps, [Rinoa] is getting a few minutes of power on her laptop. With a stack of supercaps that take up about the same volume as this already think Thickpad, [Rinoa] can play a few turns of her favorite late-90s turn-based strategy game. It’s not much, but it does work.

Check out [Rinoa]’s video below.

Filed under: laptops hacks

How Good Is Your Aim First Thing In The Morning?

เสาร์, 03/04/2017 - 07:00

For the less than highly-driven individuals out there — and even some that are — sometimes, waking up is hard to do, and the temptation to smash the snooze button is difficult to resist. If you want to force your mind to immediately focus on waking up, this Nerf target alarm clock might get you up on time.

Not content to make a simple target, [Christopher Guichet] built an entire clock for the project. The crux of the sensor is a piezoelectric crystal which registers the dart impacts, and [Guichet]’s informative style explains how the sensor works with the help of an oscilloscope. A ring of 60 LEDs with the piezoelectric sensor form the clock face, all housed in a 3D printed enclosure. A rotary encoder is used to control the clock via an Arduino Uno, though a forthcoming video will delve into the code side of things; [Guichet] has hinted that he’ll share the files once the code has been tidied up a bit.

Even though there are commercial options out there for crazy alarm clocks, that should not stop you from putting together your own custom version that will get you up in the future.

[Thanks for the tip, Itay!]

Filed under: clock hacks

Using Backscatter Radio for a Soil Sensor Network

เสาร์, 03/04/2017 - 04:00

With almost 8 billion souls to feed and a changing climate to deal with, there’s never been a better time to field a meaningful “Internet of Agriculture.” But the expansive fields that make industrial-scale agriculture feasible work against the deployment of sensors and actuators because of a lack of infrastructure to power and connect everything. So a low-power radio network for soil moisture sensors is certainly a welcome development.

We can think of a lot of ways that sensors could be powered in the field. Solar comes to mind, since good exposure to the sun is usually a prerequisite for any cropland. But in practice, solar has issues, the prime one being that the plants need the sun more, and will quickly shade out low-profile soil-based sensors.

That’s why [Spyros Daskalakis] eschewed PV for his capacitive soil moisture sensors in favor of a backscatter technique very similar to that used in both the Great Seal Bug and mundane RFID tags alike. The soil sensor switches half of an etched PCB bowtie antenna in and out of a circuit at a frequency proportional to soil moisture. A carrier signal from a separate transmitter is reflected off the alternately loaded and unloaded antenna, picking up subcarriers with a frequency proportional to soil moisture. [Spyros] explains more about the sensor design and his technique for handling multiple sensors in his paper.

We really like the principles [Spyros] leveraged here, and the simplicity of the system. We can’t help but wonder what sort of synergies there are between this project and the 2015 Hackaday Prize-winning Vinduino project.

[via RTL-SDR.com]

Filed under: misc hacks, radio hacks

Making Laser Cutter Designs Work in a 3D Printer

เสาร์, 03/04/2017 - 02:31

The main mechanical tools in a hacker’s shop used to be a drill press and a lathe. Maybe a CNC mill, if you were lucky. Laser cutters are still a rare tool to find in a personal shop, but today’s hackers increasingly have access to 3D printers. What happens when you have a design for a laser cutter (2D parts) but only have access to a 3D printer? You punt.

[DIY3DTECH] has a two-part video on taking a 2D design (in an SVG file) and bringing it into TinkerCad. At that point, he assembles the part in software and creates a printable object. You can see the videos below.

Honestly, on the face of it, this doesn’t sound very complicated. But like anything else, it isn’t always as straightforward as it seems. Watching someone work through the process will help you when you try to do it on your own. Keep in mind that while the laser-cut piece will fit with tabs, the 3D printed part won’t need them. There are other concerns he covers too, like aligning the infill to make the part stronger.

To demonstrate, [DIY3DTECH] devotes a video to converting a 2D fixture for holding wipes. The second video shows the printed result and gives some advice on the printing process. Laser cutters–for example–don’t usually warp, but that’s not true for all 3D printer material.

If you like watching someone work through their 3D printing design process, you can’t go wrong with the videos for a 3D printed vise. If you are pining for the wood that you would use in a laser cutter, maybe you need to try some exotic filaments.

Filed under: 3d Printer hacks

Record Players Explained for the Streaming Generation

เสาร์, 03/04/2017 - 01:01

How do you consume your music, these days? Aside from on the radio, that is. Do you play MP3 or other files on your phone and computer, or perhaps do you stream from an online service? If you’re really at the cutting edge though you’ll do none of those things, because you’ll be playing it on vinyl.

The legendary Technics SL1200 direct-drive turntable, as used by countless DJs. Photo by Dydric CC-BY-SA 2.5A few years ago reporting on a resurgence of sales of vinyl records was something you would never have expected to see, but consumer tastes are unpredictable. Our red-trousered and extravagantly bearded hipster friends have rediscovered the glories of the format, and as a result it’s popping up everywhere. For those of us who are old enough to have genuinely been into the format before it was cool again, the sight of Sergeant Pepper and Led Zeppelin II on 12″ at outrageous prices on a stand at the local supermarket is a source of amusement. It’s good to see your first love back in vogue again, but is it really the £20($25) per album kind of good?

With the turntable having disappeared as an integral part of the typical hi-fi setup the new vinyl enthusiast is faced with a poor choice of equipment. Often the best available without spending serious money at an audiophile store is a USB device with the cheapest possible manufacture, from which the playback will be mediocre at best. We’ve lost the body of collective knowledge about what makes a good turntable to almost thirty years of CDs and MP3s, so perhaps it’s time for a quick primer.

If you talk to a certain type of audiophile you will encounter a barrage of myth and pseudoscience on almost any topic relating to audio, and vinyl is no exception. It’s simplest for the purposes of this article to say that it is possible to play back a vinyl record such as to achieve a very high standard of audio reproduction given good quality equipment, and leave it at that. We’re not going to descend into audiophile fantasy, nor are we going to wax lyrical about turntables that will cost you more than your car. Instead we’re going to look at what makes a turntable, and hopefully help you pick one which will neither damage your records or sound bad.

How Vinyl Recordings Work

Close-up magnification of a 45RPM vinyl record, showing the audio waveform in each groove. The red lines are 1mm apart. Public domain photo by Alex:D.There was a time when describing the operation of a record player would have been unnecessary as they were ubiquitous, but we want this to be a primer to serve all generations so it’s worth a quick diversion.

A record is a thin plastic disc into the surface of which is cut a spiral groove. Analogue audio is expressed as variations in the wall of the groove, and played back through a needle being placed in the groove and held stationary as the record is rotated anticlockwise on a turntable.

The vibrations of the needle are converted into electrical audio signals which are amplified for your hi-fi system. The discs hold recordings on both sides, and can be found in 12″, 10″, and 7″ variants. Long-playing albums typically require a rotation speed or 33⅓ RPM, while singles usually rotate at 45RPM. You’ll also see reference to earlier 78RPM records and rare 16RPM talking book records, but they are out of the scope of this article.

The groove itself would originally have carried mono audio, but later recordings were adapted for stereo by expressing the right and left channels in its opposing walls. An equalisation curve is applied to the audio before recording in the vinyl, this reduces the bass and thus the area taken up by the groove and the chance of the needle jumping out of it. A corresponding reverse curve must be applied in your playback device’s preamplifier, this is referred to as the RIAA curve after the industry organisation that specified it. The best visualization we’ve ever see for these grooves is with an electron microscope; and amazing trick performed by Ben Krasnow.

A youthful rite of passage for hackers of old was to play music from a record with a piece of paper inserted into the split end of a sharpened matchstick that formed the needle, this serves to demonstrate how accessible and simple this technology can be. Despite this simplicity though, to achieve good playback results you’ll need something a little better. We’ll now go through the individual components of your record player, describe their operation and varieties, and help you spot the good and the bad.

The Platter And Drive A substantial aluminium platter on a belt drive turntable, with its mat removed.

It’s easy to describe the complete device you’ll play back your vinyl on as a turntable, without considering the turntable itself as an important component. We’ll now take a minute to look at it, and split it into its components: platter, bearing, and drive system.

The platter provides the circular flat surface upon which the record sits as it rotates. It will often have a rubber or similar mat on top of it to provide an acceptable surface to avoid damaging the record. The job of the platter is to rotate without vibration or flexing, so a good platter should be rigid, greater than the size of a 12″ record, and have a significant mass. You’ll see them most frequently as aluminium castings, though high-end turntables have been made of a wide variety of materials. By contrast cheap turntables almost always have lightweight plastic platters that provide no damping, and easily warp.

Jockey wheel drive on an ancient and rather grubby 1950s turntable.

The bearing at the centre of the platter has the job of allowing rotation to continue without excess friction or vibration. There are platters that float on a layer of oil, spin on ball bearings, rest on a tapered spindle, and more. Cheap plastic platters will often have minimal attention to this important component, instead simply resting at the bottom of the spindle and relying on the friction between plastic and metal being low enough that the drive system can overcome it.

To rotate, the platter must have a drive system, and this is often touted as a marketing feature of the complete turntable. The drive does not have to be particularly powerful except in special applications such as DJ turntables, it simply has to be as smooth and vibration-free as possible and rotate the platter at the correct speed. Ancient turntables may have a jockey-wheel drive against a rim on the underside of the platter, but you’ll want to look for either a belt drive or a direct drive. Belt drives as their name suggest insulate the platter from vibrations through a rubber belt, while direct drives couple the platter directly to the shaft of a motor.

The belt-drive mechanism in close-up. The lever on the left changes speed by shifting the belt between different widths of the motor spindle.

The choice of motor on a turntable is important, for through the motor comes most of the vibration that can affect playback. Look for twin-pole AC motors in a belt-drive turntable, and avoid shaded-pole motors. Very cheap plastic belt drive turntables often have small and vibration-happy DC motors.

Direct drive motors by comparison will often have the rotor magnets fixed in a ring on the underside of the platter, locating over a ring of stator electromagnets on the turntable chassis. They will be driven by a multiphase AC supply in a similar manner to a stepper motor, and the quality of both motor and drive will depend on the price of the unit. The legendary Technics SL1200 series turntables as used by countless DJs use this arrangement, though it’s arguable whether or not their high cost owes more to the legend than the reality.

The Tonearm

The tonearm takes the form of a balanced arm on a pivot that carries the cartridge and needle assembly over the record, and has to ensure that the correct forces are exerted on the record by the needle. Too much force either downwards or sideways will compromise playback quality and damage both record and needle.

The tonearm fulcrum, showing typical tracking weight and anti-skate adjustments.

A tonearm should have two accessible adjustments, tracking weight and anti-skate force. The tracking weight and anti-skate force settings should be defined by the manufacturer of your cartridge and needle, and will be specified in grammes. Cheap turntables will have these preset by the manufacturer or may miss them entirely, their presence is a good indication that the turntable is of some level of quality.

The tracking weight is simply the weight exerted by the needle on the record, and it will normally be in the region of a gramme or so. In most cases it is set by means of a counterweight on the other end of the tonearm that can be moved back and forth on a screw thread. There should be a dial on the counterweight calibrated in grammes. To set the tracking weight, first adjust the weight until the tonearm balances on the level, then adjust the weight back until the required tracking weight setting is shown on the dial.

The anti-skate force is a force applied to the tonearm that pulls it towards the edge of the record. This counteracts the force applied to the tonearm towards the centre of the record by the friction of the disc, with the desired result of reducing groove wear. There is usually a spring that is tightened or loosened by means of a small calibrated knob, simply turn to the value in grammes.

The tonearm itself can be found in a variety of different shapes, both straight and curved. It should be a metal tonearm, avoid turntables with plastic tonearms as a tonearm should be as rigid as possible. There are a lot of audiophile theories about the perfect shape for a tonearm, but the idea is to ensure that the cartridge axis is always at right angles to the groove and that the arc it tracks is as good an approximation to a straight line as possible. You’ll find hotly contested arguments over straight tonearms versus S-shaped ones, but you are probably better placed concerning yourself with your tonearm’s quality than its shape.

The Cartridge And Needle An Ortofon moving-magnet cartridge in its removable headshell.

The business end of a turntable is a tiny diamond needle that sits in the groove on the record, and transmits the vibrations up its mounting arm to a cartridge. The cartridge converts these vibrations into electrical impulses, which are sent down the wires to your RIAA preamp — the “Phono” input on your amplifier. On some turntables the cartridge sits in a removable headshell rather than being attached directly to the end of the tonearm.

You will see three types of cartridge, in ascending order of quality of price: ceramic, moving magnet, and moving coil. Ceramic cartridges use a piece of piezoelectric ceramic to generate the audio signal and are typically found on cheap turntables, while most reasonable quality cartridges will be moving magnet designs in which a tiny magnet vibrates within a coil of wire. High-end audiophiles will probably go for moving-coil designs in which the magnet stays stationary and the coil vibrates.

As long as the needle is not worn or damaged, and the tonearm adjustments have been made correctly, it should not matter in terms other than audio quality which type of cartridge you use. However you do not have to descend into audiophile silliness to find a decent moving-magnet cartridge to be a better choice than a ceramic one.

Mounting The Turntable

If you’ve made it this far you’ll have gained an understanding that vibration is the chief enemy of the turntable owner. We’ve talked about vibration from the drive system, but what about that from the environment?

There was a time when a cheap “Music centre” hi-fi would have a plastic turntable moulded into its top. It would be an integral part of the unit, and any vibrations in the surrounding environment from traffic or passers-by would find their way directly to the needle. Thus you had to tread carefully, or else the record would skip and jump.

Higher quality turntables will thus incorporate some form of spring and damper system, with the aim of removing these vibrations before they can affect playback. Typically this will mean a set of springs preloaded by the mass of the turntable, but you may find elaborate oil-filled damper systems as well. You will need to ensure that your turntable incorporates some kind of suspension.

So… What Should I Look For?

If you’ve read the advice above, you should now have some idea of what makes a decent turntable. You are looking for rigid components and as vibration free a design as possible, a rigid platter with some mass coupled to a belt or direct drive, with a good quality metal tonearm and a moving-magnet cartridge. If you consult your favourite hi-fi store you’ll find these attributes aplenty in new turntables, but you should expect to pay at least a three-figure sum for them. Avoid plastic turntables at all cost, and pass over the cheap turntables designed primarily for recording your LPs through USB.

If you can’t afford a new turntable, what are your options? There are many decades’ worth of secondhand audiophile turntables out there and you can find bargains, however beware that you’re not paying over the odds for something where a new equivalent would be a better bet. If you’re really strapped for cash though, hit the want ads and the thrift stores. Or ask your older relatives whether their 1970s hi-fi is still gathering dust in the loft. Often the turntable supplied with decent quality mass-market hi-fi systems in the 1970s was surprisingly well-made, and a bit of legwork can still land you one of these unloved and overlooked units for very little money indeed. The turntable in most of the photos on this page for example is an unremarkable JVC turntable from the 1970s with a 2-pole AC motor and a hefty aluminium platter, picked up for a song a few years ago in a junk shop.

It’s important to remember with analogue audio that the most important link in the chain is the first one. Put a bit of effort into sourcing a turntable, and it will reward you.

Filed under: Hackaday Columns, home entertainment hacks, Interest

Amazon S3: Out Like a Light; On Like a Bathtub

ศุกร์, 03/03/2017 - 23:30

You no doubt heard about the Amazon S3 outage that happened earlier this week. It was reported far and wide by media outlets who normally don’t delve into details of the technology supporting our connected world. It is an interesting thing to think that most people have heard about The Cloud but never AWS and certainly not S3.

We didn’t report on the outage, but we ate up the details of the aftermath. It’s an excellent look under the hood. We say kudos to Amazon for adding to the growing trend of companies sharing the gory details surrounding events like this so that we can all understand what caused this and how they plan to avoid it in the future.

Turns out the S3 team was working on a problem with some part of the billing system and to do so, needed to take a few servers down. An incorrect command used when taking those machines down ended up affecting a larger block than expected. So they went out like a light switch — but turning that switch back on wasn’t nearly as easy.

The servers that went down run various commands in the S3 API. With the explosive growth of the Simple Storage Service, this “reboot” hadn’t been tried in several years and took far longer than expected. Compounding this was a backlog of tasks that built up while they were bringing the API servers back online. Working through that backlog took time as well. The process was like waiting for a bathtub to fill up with water. It must have been an agonizing process for those involved, but certainly not as bad as the folks who had to restore GitLab service a few weeks back.

[via /r/programming]

Filed under: internet hacks

Wimshurst Machines: High Voltage from the Gods

ศุกร์, 03/03/2017 - 22:01
Wimshurst machine demo

The Wimshurst machine is one of the oldest and best known electrostatic machines, consisting of its iconic two counter rotating disks and two Leyden jars. Most often you see someone hand cranking it, producing sparks, though we’ve seen it used for much more, including for powering a smoke precipitator for cleaning up smoke and even for powering a laser.

It works through an interesting sequence of events. Most explanations attempt to cram it all into one picture, requiring some major mental gymnastics to visualize. This often means people give up, resigned to assume these work through some mythical mechanics that defy a mortal’s ability to understand.

So instead, let’s do a step-by-step explanation.

The Beginning: Charging The Sectors Overview of sectors

Each disk is covered in metal sectors on their outward facing sides. The sequence of events begins at any sector that has an unequal amount of positive or negative charge. As long as the sectors are clean and dry then there’s usually at least one that’s charged. Let’s say for example that one has a net negative charge and is on the front disk.

That net negative charge influences the nearest sector on the rear disk, repelling negative charge to the far side of it leaving the near side with a positive charge. That’s called electrostatic induction, and it’s for that reason that the Wimshurst machine is called an influence machine since the charge on one sector influences the charge distribution on another sector.

Next, let’s switch to the rear disk and look at what happens to that sector that’s been influenced.

The neutralizer bars neutralizing

The next thing that happens is the real genius. Each disk has a neutralizer bar facing it. Each end of a neutralizer bar has a brush that touches the sectors as they pass. And there are an even number of sectors. That all means that when a brush is touching a sector, the neutralizer bar is now electrically connecting that sector with another sector at the other end of the neutralizer bar. It shorts them out.

Let’s say a neutralizer brush is touching the sector that’s been influenced, the one shown above that has had its charge redistributed such that it’s positive on the side facing inward and negative on the side touching the brush. Even though the sector is neutral overall, the neutralizer bar sees only the side that’s negatively charged. It now sees an imbalance between the two sectors that its two brushes are touching. That causes a current to flow in order to restore that balance. Some of the negative charge will flow from our influenced sector to the other sector. From the neutralizer bar’s persepective, it has now neutralized the charge on the two sectors.

Influencing other sectors – rear and front views

When the disk rotates the sectors away from the neutralizer bar, the first sector is left positively charged having just had some negative charge taken from it. And having received that negative charge, the other sector is left negatively charged.

These charged sectors are rotated more to where they face sectors on the front side of the disk just when those sectors are touched by the brushes of the neutralizer bar on that side. And so the newly charged sectors influence charge in more sectors, and so on.

A helpful realization is that this influencing and neutralizing event causes one sector to make the sector facing it on the other disk become charged with an opposite charge. Our negatively charged sector created a positively charged sector. That positively charged sector, once the disk was rotated, went on to create a negatively charged sector.

Charges Whirling To Collectors Whirling charges and collectors

The front and rear disks (which are rotating in opposite directions) result in the charges as shown above.

It may take a moment to convince yourself (since you’re seeing the front and rear views side-by-side), but all negatively charged sectors are headed to the left collector and all positively charged sectors are headed to the right collector. You’ll also notice that the sectors that have just passed the collectors have had their charges, well, collected. They’re neutral overall again until they get to the neutralizer brushes, where the influencing and neutralizing we covered above recharges them.

The collectors don’t touch the sectors. Instead they have sharp points that face the sectors and have an air gap between them. This is a familiar technique which we’ve seen before in the functioning of Van de Graaff generators. Each collector has sharp points facing sectors on both disks which facilitate the transfer.

Using the left collector as an example, the negative charge on the sectors repels electrons from the points, leaving behind a positive charge. Since they are sharp points, that positive charge is crammed together resulting in a strong electric field in the gap near the points. That strong electric field tears air molecules apart and begins the process of making the air conductive, forming a bluish corona near the points. It’s that conductive air that causes the negative charge of the sectors to cross the gap to the collector. That leaves the sectors neutral again.

A similar thing happens at the right collector, just with opposite charges. Since those sectors are positive, the sectors will receive electrons from the collector, making those sectors neutral again.

But where does all that charge used for neutralizing the sectors go to and come from? That’s where the rest of the circuit plays a part.

The Leyden Jars And Spark Gap The Wimshurst machine circuit

The rest of the circuit consists of a spark gap and two Leyden jars. The two Leyden jars are just two cylindrical capacitors connected in series. The spark gap can also be thought of as a capacitor, albeit one with a dielectric that breaks down easily and that has a low capacitance compared to the Leyden jars. The spark gap is in parallel with the Leyden jars, and both are in parallel with the collectors.

That means the collectors are connected to each other through the disks but also through the Leyden jar/spark gap capacitors.

Charge that’s collected from the sectors charges up the Leyden jars and the spark gap. The Leyden jars are designed to withstand a higher voltage than the spark gap so it’s the spark gap that breaks down first. When it does it produces a short circuit. All the accumulated charge in the Leyden jars quickly dumps through the spark gap as a spark, neutralizing the Leyden jars until the charging process starts again.


In summary, through induction, the neutralizer bars are tricked into charging the sectors. The collectors collect that charge and store it in Leyden jars and the spark gap. When the charge has resulted in a sufficient potential across the spark gap a spark occurs, shorting out the Leyden jars until enough charge can be collected again for another spark.

But as we said, they can be used for more than just producing sparks. Two examples we’ve seen here on Hackaday are for powering a smoke precipitator and for powering a TEA laser.

Filed under: classic hacks, Engineering, Featured

Glitchy Synthesizer Meets Honeycomb LED Matrix

ศุกร์, 03/03/2017 - 19:01

Don’t watch [Jason Hotchkiss]’s video if flashing lights or bleepy-bloopy synthesizer noises give you seizures. Do watch, however, if you’re interested in a big honeycomb-shaped LED matrix being driven at audio frequencies through a dedicated square-wave synthesizer that’s built in.

The LED panel in question is housed in a snazzy laser-cut, honeycomb-shaped bezel: a nice change from the standard square in our opinion. The lights are 1/2 watt (whoa!) whites, and the rows and columns are driven by transistor drivers that are in turn controlled by shift registers. We’re not entirely sure how the matrix is driven — we’d love to see a circuit diagram — but it looks like it’s some kind of strange, non-scanning mode where all of the column and row drives are on at once. Whatever, it’s art.

And it’s driven by logic chips making audio-frequency square waves. Two of these are fed into an LFSR and into an R-2R DAC and then into the shift registers. The output is chaos, but the audio and the visuals do seem to influence each other. It’s an audio-visual embodiment of some of my wildest Logic Noise fantasies. Pretty cool. Enjoy the video.

Filed under: musical hacks, video hacks

Raiders of the Lost OS: Reclaiming A Piece of Polish IT History

ศุกร์, 03/03/2017 - 16:01

In today’s digital era, we almost take for granted that all our information is saved and backed up, be it on our local drives or in the cloud — whether automatically, manually, or via some other service.  For information from decades past, that isn’t always the case, and recovery can be a dicey process.  Despite the tricky challenges, the team at [Museo dell’Informatica Funzionante] and [mera400.pl], as well as researchers and scientists from various museums, institutions, and more all came together in the attempt to recover the Polish CROOK operating system believed to be stored on five magnetic tapes.

Originally stored at the Warsaw Museum of Technology, the tapes were ideally preserved, but — despite some preliminary test prep — the museum’s tape reader kept hanging at the 800 BPI NRZI encoded header, even though the rest of the tape was 1600 BPI phase encoding. Some head scratching later, the team decided to crack open their Qualstar 1052 tape reader and attempt to read the data directly off the circuits themselves!!

Using an Arduino Mega as a sampling device and the tape in test mode, the team were able to read the tapes, but the header remained inscrutable and accompanied by errors in the rest of the data. Promising nonetheless!

Switching gears, the decision was made to use a logic analyzer to read the tapes and use software to decode the data. While they waited for their new analyzer to ship, one of the team members, [Jacob Filipowicz] harnessed the power of Python to write a program called Nine Track Labs (pictured below) which would allow them to read any kind of magnetic tape, at any speed, BPI, and writing standard. Armed with the software and analyzer, the team was able to successfully recover the data from the tapes in its entirety without errors!

Among the data recovered, there were numerous versions of the CROOK operating system — allowing them to reproduce the OS’s development process, as well as hundreds of other files containing programs and tools hitherto believed to be lost. There was also a backup of a ‘live’ MERA-400 system with a binary CROOK-3 OS, ready to run in emulation. All things considered, the techno-archeological tour-de-force was a smashing success.

If — in your more modern travels — you need to recover an audio recording gone awry, know that you can retrieve that data with a hex editor.

Filed under: classic hacks, computer hacks, slider

Speech to Sign Language

ศุกร์, 03/03/2017 - 13:00

According to the World Federation of the Deaf, there are around 70 million people worldwide whose first language is some kind of sign language. In the US, ASL (American Sign Language) speakers number from five hundred thousand to two million. If you go to Google translate, though, there’s no option for sign language.

[Alex Foley] and friends decided to do something about that. They were attending McHack (a hackathon at McGill University) and decided to convert speech into sign language. They thought they were prepared, but it turns out they had to work a few things out on the fly. (Isn’t that always the case?) But in the end, they prevailed, as you can see in the video below.

The heart of the project is a pair of 3D-printed hands. At first, they accidentally printed two left hands. They printed a right hand quickly, but they found out later they were missing one segment which they wound up carving out of wood. Fishing line formed tendons and there were enough servos to require two CPU boards to drive everything.

The speech recognition is from Nuance and if listen closely to the video, you’ll see they are signing “hello” and “goodbye.” We’ll have to take their word for it that the signing is correct and legible.

This reminded us of the sign language gloves from the Hackaday Prize. These hands probably won’t advance the state of the art in prosthetics, but that wasn’t what they were going for.

Thanks to [Butter] for the tip.

Filed under: 3d Printer hacks, Arduino Hacks

The Best of Both Worlds: Arduino + 555 Should Confuse Commenters

ศุกร์, 03/03/2017 - 10:00

Hardly a week goes by that some Hackaday post doesn’t elicit one of the following comments:

That’s stupid! Why use an Arduino when you could do the same thing with a 555?


That’s stupid! Why use a bunch of parts when you can use an Arduino?

However, we rarely see those two comments on the same post. Until now. [ZHut] managed to bring these two worlds together by presenting how to make an Arduino blink an LED in conjunction with a 555 timer. We know, we know. It is hard to decide how to comment about this. You can consider it while you watch the video, below.

On the plus side, there probably is a use case for this. The LED will blink with absolutely no intervention from the Arduino. You could put the Arduino in deep sleep, if you wanted to and that LED will still blink. With a little work, you could probably adapt this idea to any number of circuits out of the 555 playbook, like a PWM generator, for example.

There’s almost nothing a 555 can’t do. If you want to see what’s under its expressionless face, this teardown is an interesting read. We just hope the comment section doesn’t overload like a Star Trek computer being asked by Captain Kirk to compute every digit of pi.

Filed under: Arduino Hacks

Wireless Doorbell Hacked Into Hands-on MQTT Tutorial

ศุกร์, 03/03/2017 - 07:00

The project itself is very simple: getting push notifications via MQTT when a wireless doorbell sounds. But as [Robin Reiter] points out, as the “Hello, world!” program is a time-honored tradition for coders new to a language, so too is his project very much the hardware embodiment of the same tradition. And the accompanying video build log below is a whirlwind tour that will get the first-timer off the ground and on the way to MQTT glory.

The hardware [Robin] chose for this primer is pretty basic – a wireless doorbell consisting of a battery-powered button and a plug-in receiver that tootles melodiously when you’ve got a visitor. [Robin] engages in a teardown of the receiver with attempted reverse engineering, but he wisely chose the path of least resistance and settled on monitoring the LEDs that flash when the button is pushed. An RFduino was selected from [Robin]’s ridiculously well-organized parts bin and wired up for the job. The ‘duino-fied doorbell talks Bluetooth to an MQTT broker on a Raspberry Pi, which also handles push notifications to his phone.

The meat of the build log, though, is the details of setting up MQTT. We’ve posted a lot about MQTT, including [Elliot Williams]’ great series on the subject. But this tutorial is very nuts and bolts, the kind of thing you can just follow along with, pause the video once in a while, and have a working system up and running quickly. There’s a lot here for the beginner, and even the old hands will pick up a tip or two.

Filed under: Arduino Hacks, home hacks

Good USB – Protecting Your Ports With Two Microcontrollers

ศุกร์, 03/03/2017 - 04:00

If you’ve ever needed an example of why you should not plug random USB peripherals into your computer, you need only look at BadUSB. The BadUSB attack relies on the fact that the microcontroller inside every USB device is a black box. If you plug a USB thumb drive into your computer, the microcontroller could quickly set up an additional network interface, forward all your traffic to the attacker’s server, and still keep serving up all those files and documents on the drive. Do you want a thumb drive that attaches a virus to every file? Bad USB can do that.

Until now, there is no cure or fix for a device using an implementation of BadUSB. [Robert Fisk] just came up with the first prophylactic USB device, designed to keep BadUSB off your computer. He’s calling it USG, and it’s basically a hardware firewall for USB devices.

The basic design of the system goes something like this: take an ARM microcontroller with a USB host port, take another microcontroller with a USB device port, and have these devices talk to each other over SPI. The command protocol between these two microcontrollers is very simple, and thus decreases the attack surface.

[Robert] is building USG dongles, but in the spirit of Open Hardware and verifiable hardware, he’s also released a design based on two dev boards wired together. This DIY version is basically two STM32F4 dev boards smashed together with bodge wires. The total cost – less solder and a JTAG programmer – is about $50 USD. No, it doesn’t look as pretty as [Robert]’s commercial version of USG, but it does the same job of keeping your computer safe from BadUSB devices.

Filed under: Microcontrollers, peripherals hacks

iPad Tossed Out for RetroPie Arcade Cabinet Redux

ศุกร์, 03/03/2017 - 02:31

The naming and remixing in this project can get a little confusing to those unfamiliar with the different elements involved, but what [John Gerrard] has done is take a stylish mini arcade cabinet intended as a fancy peripheral for an iPad and turned it into an iPad-free retro arcade gaming cabinet. He also designed his own power controller for graceful startup and shutdown.

The project started with a peripheral called the iCade (originally conceived as a fake product for April Fool’s) and [John] observed it had good remix potential for use as a mini retro gaming cabinet. It was a good starting point: inexpensively purchased off eBay with suitable arcade-style joystick and buttons, a nice layout, and plenty of hacking potential. With a small variety of hardware from familiar sources like eBay and Aliexpress, [John] rounded up most of what he needed.

The core of the new machine is RetroPie on a Raspberry Pi 3, and the screen is a replacement iPad 2 LCD combined with a controller that accepts HDMI. The display matches the cabinet well and the adapter allows for easy interface with the Raspberry Pi 3.

The cabinet’s buttons and joystick are re-wired to an Arcade USB controller. Other additions include speakers and Player 1/Player 2 start buttons. We’ve seen scratch-built RetroPie mini cabinets but [John] made excellent use of the existing hardware of the iCade, even going the extra mile and turning the fake 25 cent coin slot into a touch-sensitive button to add credits. The end result works, looks great, and is only a black bezel for the LCD away from being completely done.

Filed under: hardware, Raspberry Pi

Review: Antex TCS 50W Digital Temperature Controlled Soldering Iron.

ศุกร์, 03/03/2017 - 01:00

Sometime last summer, I suffered a very sad loss indeed. My soldering iron failed, and it was not just any soldering iron, but the Weller Magnastat temperature-controlled iron that had been my iron of choice since my student days. It was time to buy a replacement, and a whole world of soldering equipment lay before me. In the end I settled on a choice that might seem unexpected, I bought an Antex TCS 50W temperature controlled iron with a digital temperature controller and LCD display in its handle.

No room for a poor iron

When looking at a new iron it’s worth considering for a moment what requirements you might have.  After all, while we’d all love to own a top-of-the range soldering station it’s sometimes necessary to target your purchase carefully for an acceptable blend of affordability, reliability, and performance. It’s possible to find temperature controlled irons for astoundingly low prices these days, thanks to the wonders of globalised manufacturing. But the irons themselves will not be of good quality, their bits will be difficult to replace, and sometimes they are better described as variable temperature rather than temperature controlled. If I was to escape a poor choice I’d have to set my sights a little higher.

Antex are a perennial in the world of British electronics, their signature yellow-handled irons have been around for decades. They aren’t priced at the top end of the market yet they have a pretty good reputation, but could their all-in-one temperature controlled iron be a good alternative to a unknown-name iron that came with a soldering-station-style controller? I parted with my £55 (about $68) before taxes, and waited for the delivery.

All-in-one, win or bin?

The iron I chose is the latest in a long line of their all-in-one temperature controlled irons, and so the blurb tells me, the first with digital control. Previous models had an analogue adjustment which if I recall correctly was achieved by means of a screw, while this one has an LCD display with up and down buttons on its handle.

I haven’t bothered with the supplied stand, as you can see.

In the box are the iron, a rather useless stand made from metal sheet, and an instruction leaflet. Fortunately my requirements included a decent stand, so I’d already ordered the more substantial companion product with a sponge. Out went the sponge and in went a bundle of brass turnings, but the stand itself is fine.

The iron has the usual Antex bit that fits as a sleeve over the cylindrical element. I bought a range of bits of different sizes, it’s never a bad thing to have choice. The handle is bigger than their standard irons as you might expect, but has a flattened and curved profile that’s easy on the hand. It’s noticeably lighter than the Magnastat, which along with its extra-flexible silicone cable makes it easier to use than its predecessor.

In use, the extra length of the handle doesn’t compromise soldering ability. In the time since purchase it has been used to construct multiple projects, and everything from the smaller surface-mount components upwards are taken in its stride. The 50 W element has plenty of power for soldering to PCB planes that suck away the heat, though you probably wouldn’t use it to solder heavy-gauge copper.

The temperature range of 200 to 450 Celcius is ample for my requirements, in fact once I’d set it to my normal 360 degrees I’ve never changed it. Time from power-on to full working temperature is about 45 seconds, which isn’t the fastest on the block, but then again since I turn it on when I sit down it’s not ever been an issue.

A match made in heaven

So, based on quite a few months of regular use, I’m happy with my iron. The question is though, was it the best choice? I think so, given that the competition at the price would almost certainly not come with such readily available support. There’s almost an instinctive distrust of all-in-one temperature-controlled irons that I haven’t found to be justified by the reality. An alternative might have been to build one of the clever designs that adds a temperature controller to a Weller tip, but given that this is an iron I sometimes use to earn a living I’d rather be working for cash than working on my iron. There are certainly cheaper irons and there are probably better irons, but for me this one hits the sweet spot between the two sets of being a good enough iron without being too expensive.

Filed under: reviews

Chicago to Host Hackaday Unconference

พฤ, 03/02/2017 - 23:31

We’re excited to announce that Chicago will play host to the Hackaday Unconference on March 18th. We are happy to expand our unconference plans to include this event at Pumping Station One from 1-8pm on 3/18.

Astute readers will notice that this is the second location we have announced this week. On Monday we shared the news that San Francisco would host an unconference. Hackaday’s [Sophi Kravitz] and [Jordan Bunker] are organizing things in SF. [Brian Benchoff], [Bob Baddeley], and [Mike Szczys] will be in Chicago for this event that takes shape based on what you find most interesting.

We’re excited that PS:One is opening their doors for us. We’ll make sure there’s food, beverage, some exciting hardware-based door prizes, and other select swag.

Hackaday Unconference is Based on You

The Hackaday Unconference is all about finding interesting talks from anyone who attends. If you go, and you definitely should, be ready to stand up and deliver eight minutes on something that you find interesting right now. The day will start by going around and asking everyone for a talk title or topic. We’ll all make a collective decision on the schedule for the day and roll with it as talks are bound to spawn extemporaneous discussion and follow up presentations that build on the most exciting of concepts. Unconferences are interactive and not bound by the traditional presenter/audience divide of a conference.

You may speak about anything you like, but it sometimes deciding what to talk about is easier if there are some constraints. Consider the theme of the Hackaday Unconference to be Build Something That Matters. You hear this a lot from us because we think it is important. There is immense talent and incredible experience found in the Hackaday community and we like to take some time in life to direct that for the good of all people. If you have an idea to direct creative energy toward high ideal, it’s likely to make a great presentation.

Soak Up the Excitement to Propel Your Next Project

Pressure is low, excitement is high, and the potential for something spontaneous and awesome to happen is palpable. The ‘here and now’ aspect of an unconference sets it apart from events where speakers, talk subjects, and slide decks are decided upon weeks ahead of time. RSVPs will fill up. Don’t miss out on this chance to jumpstart your excitement for a current project, or to discover the direction of your next adventure.

Filed under: cons, Hackaday Columns, slider