Science

1407 Articles

Racing Cars On A PCB

November 24, 2022 by 14 Comments

Carl Friedrich Gauss was, to put it mildly, a polymath responsible for a large percentage of the things we take for granted in the modern world. As a physicist and mathematician he pioneered several fields of study including within the field of magnetism. But since he died decades before the first car was built, it’s unlikely he could have imagined this creation, a magnetic slot-car race track called the Gauss Speedway by [Jeff McBride], which bears the name of the famous scientist.

The Gauss Speedway takes its inspiration from a recent development in robotics, where many small robots can travel around a large area with the help of circuit traces integrated into their operating area. With the right current applied to these traces, magnetic fields are generated which propel the robots. [Jeff] wanted to build something similar, integrated into a printed circuit board directly, and came up with the slot car idea. The small cars have tiny magnets in them which interact with the traces in the PCB, allowing the cars to move with high precision around the track. He did abandon the traditional slot car controller in favor of a push-button style one directly on the PCB too, which means everything is completely integrated.

While this was more of a demonstration or proof-of-concept, some of the features of this style of robot can be seen in this video, which shows them moving extremely rapidly with high precision, on uneven surfaces, or even up walls. Magnetic robots like these are seeing quite a renaissance, and we’ve even seen some that use magnetism to shape-shift.

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Fuel Cell Catalyst: Less Is More

November 22, 2022 by 14 Comments

A fuel cell is almost like a battery that has replenishable fuel. Instead of charging a battery with an electric current, you recharge a fuel cell with something like hydrogen or you simply consume it from a tank much as an internal combustion engine consumes gasoline. However, fuel cells usually use a catalyst — it isn’t consumed in the reaction, but it is necessary and many fuel cells use platinum as a catalyst which is expensive. But what if you could use less catalyst and get a better result? That’s what researchers in Canada and the US are claiming in a recent paper. The key isn’t how much catalyst they are using, but rather the shape of the catalyst.

Of course, everyone wants to use less of the expensive catalyst but polymer electrolyte fuel cells have had a particular problem where reducing the amount of catalyst used causes a disproportionate drop in cell performance. This new approach uses spherical catalyst support that improves the distribution and utilization of the catalyst.

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New Metric Prefixes Get Bigger And Smaller

November 22, 2022 by 72 Comments

It always fascinates us that every single thing that is made had to be designed by someone. Even something as simple as a bag and box that holds cereal. Someone had to work out the dimensions, the materials, the printing on it, and assign it a UPC code. Those people aren’t always engineers, but someone has to think it out no matter how mundane it is before it can be made. But what about the terms we use to express things? Someone has to work those out, too. In the case of metric prefixes like kilo, mega, and pico, it is apparently the General Conference on Weights and Measures that recently had its 27th session. As a result of that, we have four more metric prefixes to learn: ronna, quetta, ronto, and quecto.

Apparently, the new prefixes are to accommodate “big data” which is rapidly producing more data than there are atoms in the Universe. There were actually proposed earlier in a slightly different form but accepted at the conference. Apparently quecca is too close to a Portuguese swear word. So what do these actually mean? A QB (quettabyte) would be 1030 bytes while an RB (ronnabyte) is only 1027.  So 1 QB would be 1,000,000 yottabytes (YB) the previous top of the scale.

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FDA’s Approval Of Cell Culture Chicken: The Rise Of Fresh Meat Without The Animal?

November 21, 2022 by 105 Comments

On November 14th of this year, the FDA cleared the path for Upside Foods to sell its cell-culture-based chicken products within the US. This is the first product of its kind to be cleared for commercial sale within the Americas, with only Singapore having previously cleared a similar product for sale, back in December of 2020. This latter product comes courtesy of another California start-up called Eat Just.

Since that initial approval in Singapore, Eat Just has begun to set up a 2,800 square meter (~30,000 square feet) production facility in Singapore that is scheduled to begin producing thousands of kilograms of slaughter-free meat starting in the first quarter of 2023. This would make it the top-runner in the cultured meat industry, which to this point has seen dozens of start-ups, but precious few actual products for sale.

With CEO Josh Tetrick of Eat Just projecting price equality between their cultured meat and meat from animals by 2030, could the FDA’s approval herald the dawn of slaughter-free meat? There are obviously still hurdles, but as we’ll see, the idea is not nearly as far-fetched as one might think.

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solenoid wound pickup coil next to a selection of bolts and a steel rod

The Barkhausen Effect: Hearing Magnets Being Born

November 19, 2022 by 21 Comments

The Barkhausen effect — named after German Physicist Heinrich Barkhausen — is the term given to the noise output produced by a ferromagnetic material due to the change in size and orientation of its discrete magnetic domains under the influence of an external magnetic field. The domains are small: smaller than the microcrystalline grains that form the magnetic material, but larger than the atomic scale. Barkausen discovered that as a magnetic field was brought close to a ferrous material, the local magnetic field would flip around randomly, as the magnetic domains rearranged themselves into a minimum energy configuration and that this magnetic field noise could be sensed with an appropriately arranged pickup coil and an amplifier. In the short demonstration video below, this Barkhausen noise can be fed into an audio amplifier, producing a very illustrative example of the effect.

One example of practical use for this effect is with non-destructive testing and qualification of magnetic structures which may be subject to damage in use, such as in the nuclear industry. Crystalline discontinuities or impurities within a part under examination result in increased localized mechanical stresses, which could result in unexpected failure. The Barkhausen noise effect can be easily leveraged to detect such discontinuities and give the evaluator a sense of the condition of the part in question. All in all, a useful technique to know about!

If you were thinking that the Barkhausen is a familiar name, you may well be thinking about the Barkhausen stability criterion, which is fundamental to describing some of the conditions necessary for a linear feedback circuit to oscillate. We’ve covered such circuits before, such as this dive into bridge oscillators.

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Logic Via DNA

November 17, 2022 by 8 Comments

We often say you can make logic gates out of nearly anything. [Steve Mould] would agree as he just finished playing naughts and crosses (tic tac toe if you are an American) with a tray full of DNA. You can see the resulting game and how it works in the video below.

The use of DNA isn’t really significant as it simply implements a logic equation for each of the nine cells. So, for example, each cell is taken by an X (the DNA) only when certain other squares have been taken by O or not taken by O. So you essentially create an AND/OR gate using the state of each cell and its inverse.

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A two picture montage with the left montage showing a pair of hands holding an assembled and closed turbidity sensor and the right picture showing A pair of hands holding the screw on cap for the turbidity sensor and a prototype board against a backdrop of green leave

Rapid Prototyping To Measure Turbidity In Rapids

November 15, 2022 by 6 Comments

[RiverTechJess] is in the process of getting a PhD in environmental engineering and has devoted a chapter to creating a turbidity sensor for river network monitoring. Environmental sensing benefits from being able to measure accurately and frequently, so providing low cost devices helps get more data and excuse the occasional device loss that’s bound to happen when deploying electronics out in the wild. Towards this end, [RiverTechJess] has created a low cost turbidity sensor that rivals the more expensive alternatives in cost and accuracy.

The turbidity sensor is designed to be at least partially submerged allowing for the LED and light sensors to be be able to take measurements. [RiverTechJess] has made a 3D printed prototype to test the design, allowing for rapid experimentation and deployment of the sensors to work out issues. The 3D printed enclosure prototype uses rubber o-rings and “vacuum grease” to provide a watertight seal. An ESP32 microcontroller is used to store logged data on an SD card and drive the TSHG6200 850nm infrared LED and the two TSL237S-LF sensors.

The resulting paper on the turbidity sensor, in addition to the blogs of the process, provide a wealth of data that show what goes into developing and calibrating a device that is meant to be used for environmental monitoring. All source code is available on GitHub and development continues on a newer revision of the turbidity sensor with updated electronics and hardware.

We’re no strangers to water sensors and we’ve seen devices from internet connected water pollution monitors to small handheld potable water detectors.

Video after the break!

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