Harmonic Analyzer Does It With Cranks And Gears

November 17, 2019 by Lewin Day 5 Comments

Before graphic calculators and microcomputers, plotting functions were generally achieved by hand. However, there were mechanical graphing tools, too. With the help of a laser cutter, it’s even possible to make your own!

The build in question is nicknamed the Harmonic Analyzer. It can be used to draw functions created by adding sine waves, a la the Fourier series. While a true Fourier series is the sum of an infinite number of sine waves, this mechanical contraption settles on just 5.

This is achieved through the use of a crank driving a series of gears. The x-axis gearing pans the notepad from left to right. The function gearing has a series of gears for each of the 5 sinewaves, which work with levers to set the magnitude of the coefficients for each component of the function. These levers are then hooked up to a spring system, which adds the outputs of each sine wave together. This spring adder then controls the y-axis motion of the pen, which draws the function on paper.

It’s a great example of the capabilities of mechanical computing, even if it’s unlikely to ever run Quake. Other DIY mechanical computers we’ve seen include the Digi-Comp I and a wildly complex Differential Analyzer. Video after the break.

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How To Design A BGA Breakout Module

November 16, 2019 by Lewin Day 11 Comments

Surface mount devices can take some adjusting to for hackers primarily used to working with through-hole components. Despite this, the lure of the hottest new parts has enticed even the most reticent to learn to work with the technology. Of course, time rolls on and BGA parts bring further difficulties. [Nate] from SparkFun worked on the development of the RedBoard Artemis, and broke down the challenges involved.

The RedBoard Artemis is an Arduino-compatible devboard built around the Ambiq Apollo3 chip. In addition to packing Bluetooth and 1 MB of Flash, it’s also capable of running TensorFlow models and using tiny amounts of power. The chip comes in an 81-Ball Grid Array at 0.5mm pitch, which meant SparkFun’s usual PCB fabrication methods weren’t going to cut it.

An initial run of prototype boards was run using 4 layers, blind and buried vias, and other fancy tricks to break out all the necessary signals. While this worked well, it was expensive and inefficient. The only part of the board that needed such fabrication was around the chip itself; the rest of the board could be produced with cheaper 2-layer methods. To improve this for mass production, instead, an SMD module was created to house the Apollo3, which could then be dropped into new designs on cheaper boards as necessary.

[Nate] does a great job of explaining the engineering involved, as well as sharing useful tips for others going down a similar path. So far, this is just part 1, with future posts promising to cover the RF shield design and FCC certification process. [Nate] has always been keen to share his wisdom, and we can’t wait to see what comes next!

Double Pendulum Uses Custom Slip Rings

November 15, 2019 by Lewin Day 11 Comments

Rotating mechanisms can be a headache when it becomes necessary to deliver power through them. [Igor Brkic] faced just such a challenge when creating his double-pendulum build, and solved it with a little DIY.

The project is known as KLAATNO, inspired by the Croatian word for pendulum, klatno. It’s a mechanical installation piece, consisting of a power-assisted pendulum, with a second pendulum fitted at the end of the swinging arm. A 24 volt geared motor is used to drive the assembly. It’s controlled by an Arduino Pro Mini, which measures the back EMF from the motor terminals to determine the speed and direction of the motor’s movement.

To make the installation more visually striking, EL wire was installed on the swinging arms of the twin pendulums. This required the transfer of power to the rotating assembly, which was achieved through the use of custom made slip rings. Copper sheet is used in combination with a flexible metal wire sourced from a guitar string. It’s not as low-friction as [Igor] would like, but it gets the job done.

It’s a fun installation that would be perfectly at home in the common area of any university engineering building. Of course, our favorite pendulums are of the siege weapon variety. Video after the break.

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Credit Card Skimmers Evolve – Shimmers Are Here

November 15, 2019 by Lewin Day 91 Comments

Credit cards are loaded with security features, but the game of cat and mouse goes on. Nefarious syndicates continue to develop technology to steal data in new and innovate ways. After SparkFun did a teardown on some illicit hardware, they were visited by local law enforcement, who requested their help once more.

[Nick] from SparkFun refers to the device in question as a “shimmer”. It’s intended to be installed inside the chip reader of a credit card terminal, in between the terminal and the user’s credit card. Fabricated on a flexible film PCB, it’s thin enough to glue inside without being obvious even during maintenance.

The investigation begins with identification of the major components on board, followed by attempts to communicate with the device. Unfortunately, the hardware was largely unresponsive, even when connected to a card reader. In an effort to learn more, a schematic was produced. [Nick]’s analysis raised more questions than answers, and the suspicion is that the hardware may have been damaged at some point. However, the basic capabilities of the device are obvious, given the ability of the hardware to interact with a card via its contacts and offload the data through the onboard nRF24L01 radio module.

Thanks to people like [Nick], and earlier work from SparkFun, we all now have a better understanding of the risks when using payment terminals out in the wild. Unfortunately, unless your local gas station is willing to let you spend 20 minutes disassembling their card reader before paying, there’s not a whole lot the individual can do about it. Stay vigilant, and if you’ve got the skinny on a skimmer, drop us a line.

Giant Analog CO2 Meter Sweeps Away Doubt

November 14, 2019 by Kristina Panos 11 Comments

Most of us are aware that trees turn CO₂ into oxygen, but we’d venture to guess that many people’s knowledge of this gas ends there. Is it feast or famine out there for the trees? Who can say? We admire [rabbitcreek]’s commitment to citizen science because he’s so focused on making it easy for people to understand their environment. His latest offering, a giant analog CO₂ meter, might be our favorite so far.

The brains of the operation is an Adafruit Feather Adalogger. It reads the CO₂ sensor that’s mounted close to the business end of the nautilus, and becomes the quill that writes the CO₂ value to a FeatherWing e-ink screen. For the giant needle, this lovely meter uses one of those fiberglass poles you mark your driveway with so you can find it under a blanket of snow. The needle is counter-balanced with washers encased in printed plastic.

As you can see in the GIF, there’s a decent delay between the CO₂ blast and the needle response — we like to imagine the CO₂ spiraling slowly through the nautilus like a heavy, ill wind on its way to gravely move the needle.

Want a way to monitor air quality that’s a bit more discreet? Slip this portable meter into your pocket.

Aging Alcohol In 30 Minutes

November 14, 2019 by Lewin Day 38 Comments

Many alcoholic beverages are aged in barrels for long periods of time. The aim is to impart flavors from the wood of the barrel into the liquid, and allow a whole host of chemical reactions to happen, changing the character of the taste. However, this takes time, and time is money. There’s potentially a faster way, however, and [The Thought Emporium] set out to investigate.

Inspired by several research papers, the goal was to examine whether using ultrasound to agitate these fluids could speed the aging process. Initial tests consisted of artificially aging milk, apple cider, and vodka in a small ultrasonic jewelry cleaner for 30 minutes, with cognac chips for flavor. Results were positive amongst the tasters, with the vodka in particular showing a marked color change from the process. A later test expanded the types of wood chip and beverages under test. Results were more mixed, but with a small sample size of tasters, it’s to be expected.

While taste is subjective, there were definite visible results from the aging process. It’s a technique that’s being explored by industry, too. We’ve seen hackers brew up plenty of tasty beverages before, too – often with a little automation thrown in Video after the break.

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Tindie Seller Reviews A Knock-Off Of His Own Product

November 13, 2019 by Dan Maloney 66 Comments

If imitation is the sincerest form of flattery, online creators are being sincerely flattered at an alarming rate these days. We Hackaday scribes see it all the time, as straight copy-pastes of our articles turn up on other websites under different bylines. It’s annoying, but given prevailing attitudes toward intellectual property rights, there’s very little point in getting upset about it anymore. But what if it’s hardware that’s being infringed upon?

Hacker and Tindie store proprietor [Brian Lough] recently ran into this problem with one of his products, but rather than get upset, he did a remarkably fair and thoughtful review of the knock-off. The board in question, a D1 Mini Matrix Shield, makes it a snap to use LED matrix panels in projects like his Tetris-themed YouTube sub counter. The knock-off came via Ali Express, with the most “flattering” aspect being the copy and the images on the Ali Express listing, some of which are pulled straight from [Brian]’s Tindie store. While the board’s layout is different, it’s pretty clear that it was strongly inspired by the original. And the changes they did make – like terminal choices and undersizing some traces – only serve to lower the quality of the knock-off. Surely this was a cost-cutting move, so they could undercut sales of the original, right? Apparently not – the knock off is more expensive. Yes, [Brian]’s board is a kit and the imitator is fully assembled, but it still begs the question of why?

Hats off to [Brian] for not only making a useful product, but for taking the time to engineer it properly and having the ambition to put it on the market. It’s a pity that someone felt the need to steal his work, but it seems to be a rite of passage these days.

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