Day: January 29, 2020

Lazydoro Mothers You Into Being Productive

January 29, 2020 by 3 Comments

The Pomodoro Technique has helped countless people ramp up their productivity since it was devised in the late 1980s. Breaking down tasks into 25 minute chunks can improve your focus tremendously, provided you show up, start the timer, and get to work.

Lazydoro takes the psychology focus even further. In [romilly.cocking]’s interpretation, a time-of-flight (ToF) sensor is your productivity Santa Claus — it knows whether you’re doing your part by simply applying butt to chair, and your present is a productive 25 minutes where not a second is wasted futzing with timers and worrying about time lost to such administrative tasks. When Lazydoro senses that you have arrived, the Raspi Zero starts a 25-minute Pomodoro timer, and represents the time remaining across a Pimoroni BLINKT LED matrix.

But hold on, you haven’t heard the best part yet. Lazydoro was designed with real life in mind, because [romilly] thought of everything. Whenever you leave your chair, a 5-minute timer starts, and there’s a beep when time is up. If you make it through the 25 minutes and hear the victory beep, then it’s break time. But if you get up too soon, the work timer stops, and the 5-minute timer becomes your limited space in which to fret, stare out the window, or get the snack you think you desperately need to keep going. This makes Lazydoro awesome even without the Pomodoro part, because simply sitting back down is a big step one.

If you make a circuit sculpture Pomodoro and stare at it on your 5-minute breaks, you might achieve productivity enlightenment.

Tensors Explained

January 29, 2020 by 30 Comments

You can do a lot of electronics without ever touching a tensor, but there are some situations in which tensors are absolutely essential. The problem is that most math texts give you a very dry description that is difficult to internalize. That’s where [The Science Asylum] comes in. Their recent video (see below) starts with the dry definition and then shows you what it means and why.

According to the video, the textbook definition is:

A rank-n tensor in m-dimensions is a mathematical object that has n indices and mn components and obeys certain transformational rules.

That sounds a lot like an array but we are not sure what “certain transformational rules” really means to anyone.

Wikipedia does a little better:

[A]n algebraic object that describes a linear mapping from one set of algebraic objects to another.

These constructs are key to anything electromagnetic (including antennas) and show up a lot in stress calculations and quantum mechanics. Even Einstien’s theory of relativity uses tensors.

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Wire Loop And Amplifier Solve Audio Problem For The Hearing Impaired

January 29, 2020 by 21 Comments

Imagine being asked to provide sound reinforcement for a meeting that occurs in a large room, where anyone can be the speaker, and in a situation where microphones would hinder the flow of the meeting. Throw in a couple of attendees who have hearing disabilities, and you’ve got quite a challenge to make sure everyone gets heard.

Such a situation faced [David Schneider] at his Quaker meetinghouse, which he ended up solving with this home-brew audio induction loop system. The worship style of conservative sects of the Religious Society of Friends, as the Quakers are formally known, is “silent worship”, where congregants sit together in silence until someone feels moved to share something. Anyone can speak at any time from anywhere in the room, leading to the audio problem.

Rooms mics and a low power FM transmitter didn’t work because those using radio as aids to hearing the service felt awkward, so [David] decided to take advantage of a feature in the hearing aids worn by some members: telecoils. These are inductive receivers built into some hearing aids to send sound directly to them using magnetic fields generated by a loop in the listening area. [David]’s loop ended up being 240 meters of 20-gauge copper wire in the attic above the meeting room. The impedance ended up close to 8 ohms, perfect for feeding directly from the speaker terminals of an old stereo amplifier. Pumping 160 Watts into the coil allows the hearing-aid wearers below hear the service now.

There’s still work to be done on the input side to improve audio quality, but [David]’s solution is elegant in that it helps those who need it most using technology they already have. And perhaps those who need but don’t yet have hearing aids can roll their own.

Building (And Testing) A DIY Air Purifier

January 29, 2020 by 64 Comments

Whether it’s the usual pollution of the city, or the fact that your corner of the globe happens to be on fire currently, poor air quality is a part of daily life for many people. One way of combating this issue is with a high quality HEPA filter in your home, but unfortunately that’s not something that everyone can afford to even has access to.

Which is why [Adam Kelly] decided to design this DIY HEPA air purifier that can be built for less than $100. That might still sound like a lot of money, but compared to the $500 sticker price he was seeing for the models recommended by health officials, it’s certainly a step in the right direction. Of course, it’s only a deal if it actually works, so a big part of the project has also been verifying the design’s ability to filter particles out of the air in a timely manner.

To build his purifier, [Adam] found a HEPA H13 rated replacement filter that was cheap and readily available, and started designing a low-cost way to pulling air through it. He eventually went with a 120 mm computer case fan coupled with a step-up converter that can produce 12 V from a standard USB port. Then he just needed to design a 3D printed “lid” which would position the fan so it draws air through the center of the filter.

In terms of testing, [Adam] wasn’t worried about the purifier’s ability to actually filter out smoke particles; unless the manufacturer lied about the capabilities of the filter itself, that part is a given. But he was curious about how effective the fan would be in terms of circulating air through a room.

By installing a pitot tube from one of his drones into the lid of the purifier, he determined the airflow in the center of the filter to be approximately 160 CFM. By his calculations, that means it should be able to circulate all the air in his 25 cubic meter office around 10 times per hour. That’s a promising start, but [Adam] says he’d still be interested in a more detailed analysis of the design’s performance by anyone who might have the equipment to do so.

As he lives in Australia, this project is more than just a passing fancy for [Adam]. He only has to look out the window to see that the air he’s breathing is filled with smoke from the raging bushfires. They say that necessity is the mother of invention, and breathable air is pretty high up on the list of human necessities. Our hat’s off to anyone who sees their fellow citizens suffering and tries to use their skills to come up with a solution.

Burning Things With Big Lasers In The Name Of Security

January 29, 2020 by 4 Comments

Several fields of quantum research have made their transition from research labs into commercial products, accompanied by grandiose claims. Are they as good as they say? We need people like Dr. Sarah Kaiser to independently test those claims, looking for flaws in implementation. At the 2019 Hackaday Superconference she shared her research on attacking commercially available quantum key distribution (QKD) hardware.

Don’t be scared away when you see the term “quantum” in the title. Her talk is very easy to follow along, requiring almost no prior knowledge of quantum research terminology. In fact, that’s the point. Dr. Kaiser’s personal ambition is to make quantum computing an inviting and accessible topic for everyone, not just elite cliques of researchers in ivory towers. You should hear her out in the video below, and by following along with the presentation slide deck (.PPTX).

Quantum Key Distribution

So why is QKD is so enticing? Unlike existing methods, the theoretical foundation is secure against any attacker constrained by the speed of light and the laws of physics.

Generally speaking, if your attacker is not bound by those things, we have a much bigger problem.

But as we know well, there’s always a difference between the theoretical foundation and the actual implementation of cryptography. That difference is where exploits like side-channel attacks thrive, so she started investigating components of a laser QKD system.

As a self-professed “Crazy Laser Lady”, part of this investigation examined how components held up to big lasers delivering power far outside normal operating range. This turned up exciting effects like a fiber fuse (~17:30 in the video) which is actually a plasma fire propagating through the fiber optic. It looks cool, but it’s destructive and useless for covert attacks. More productive results came when lasers were used to carefully degrade select components to make the system vulnerable.

If you want to learn more from Dr. Kaiser about quantum key distribution, she has a book chapter on the topic. (Free online access available, but with limitations.) This is not the first attempt to hack quantum key distribution, and we doubt it would be the last. Every generation of products will improve tolerance to attacks, and we’ll need researchers like our Crazy Laser Lady to find the reality behind advertised claims.

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DDR-5? DDR-4, We Hardly Knew Ye

January 29, 2020 by 32 Comments

This month’s CES saw the introduction of max speed DDR5 memory from SK Hynix. Micron and other vendors are also reportedly sampling similar devices. You can’t get them through normal channels yet, but since you also can’t get motherboards that take them, that’s not a big problem. We hear Intel’s Xeon Sapphire Rapids will be among the first boards to take advantage of the new technology. But that begs the question: what is it?

SDRAM Basics

Broadly speaking, there are two primary contenders for a system that needs RAM memory: static and dynamic. There are newer technologies like FeRAM and MRAM, but the classic choice is between static and dynamic. Static RAM is really just a bunch of flip flops, one for each bit. That’s easy because you set it and forget it. Then later you read it. It can also be very fast. The problem is a flip flop usually takes at least four transistors, and often as many as six, so there’s only so many of them you can pack into a certain area. Power consumption is often high, too, although modern devices can do pretty well.

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Soviet Soyuz Clock Teardown

January 29, 2020 by 24 Comments

We love spacecraft and we definitely love teardowns, especially if they are for vintage devices. [Ken Shirriff] writes about taking apart the digital clock module from the Soviet Soyuz series of spacecraft and there are a lot of interesting bits to the device. After all, it has been into space.

The Soyuz series of spacecraft made their maiden voyage in 1966, and are still flying today. The clock in question comes from somewhere in the middle, around 1996. On the outside, it seems like any spaceship gizmo, and the digital clock keeps local time along with a stopwatch and an alarm function. The guts are much more interesting with no less than 10 PCBs sandwiched inside the small enclosure.

The system consists of dual layer-boards with a mix of SMD and through-hole components that are interconnected by a series of wires that are bunched and packed to create a wiring harness. The pictures show a very clever way of setting up the stack and the system is serviceable by design as the bunch opens up like a book. This gives access to the unique looking components that include 14-pin flat pack chips, large ceramic multicoil inductors, green colored resistors, and orange rectangular diodes.

There are isolated PSU boards, control boards, clock circuitry, some glue logic to put things together, and LED displays with driver circuits. [Ken Shirriff] dives into the clocking circuit and the various parts involved along with a comparison with US technology. There is a lot of interesting detail in these boards, and it may be a source of inspiration for some.

If you are looking for more spaceborne tech, have a look at the one that stowed away on the International Space Station.

Thanks for the tip [Thorsten Eggert]

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