Electric Vehicle 1900’s Style: New Leases On Old Tech

April 8, 2021 by Al Williams 69 Comments

Excited about your new electric vehicle? Thomas Edison would be, too. He tried to produce electric vehicles for Ford around 1900. Petroleum-based vehicles dashed his dreams of the electric car, and the battery he wanted to use languished as a technological dead end. The batteries were long-lasting, sure, but they were expensive and had other problems, not the least of which was producing hydrogen gas. But that battery technology is receiving renewed interest today, because some of the things that made it a bad car battery make it good for alternate energy projects.

You wouldn’t think a century-old battery technology that was never very popular would make a comeback. But then again, who thought we’d see the return of bell-bottom pants or vinyl records? Continue reading “Electric Vehicle 1900’s Style: New Leases On Old Tech” →

Color-Changing Sutures Detect Infection

April 4, 2021 by Kristina Panos 21 Comments

If you’ve ever had surgery, you know firsthand how important it is to keep the wound from getting infected. There are special conductive sutures that sense changes in wound status via electrical signal and relay the information to a computer or smart phone. As awesome as those sound, they’re a first-world solution that is far too pricey for places that need it most — developing countries. And surgical wounds in developing countries are about four times more likely to get infected than those in the US.

Iowa high-school student [Dasia Taylor] found a much simpler solution that could drive down the infection rate. She used beets to develop color-changing sutures that turn from bright red to purple within five minutes if an infection is present.

Beets, and other fruits and vegetables like blackberries, plums, and blueberries are natural indicators of pH. They have a compound called anthocyanin that gives them both their pigment and this cool property. Beets are perfect because they change color at a pH of nine — the same pH level of infected human skin, which is normally around five.

[Dasia] experimented with several types of suture thread to see which ones would absorb the beet juice in the first place. She settled on a cotton-polyester blend that is braided. While it probably helps absorb the beet juice, it would also give bacteria several places to hide. Another problem is that many surgeries involve cutting muscle, too, and by the time a deeper infection would show up on the sutures, it would be pretty late in the game. But if these color-changing sutures can be made to be cost-effective, safe for skin, and of course, keep wounds together, this solution is way better than nothing at all and definitely worth producing. You can see [Dasia] talk about her project in the video below.

Want to know more about natural pH indicators? Sure you do.

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Reverse Engineering Silicon, One Transistor At A Time

April 3, 2021 by Jenny List 10 Comments

Many of will have marveled at the feats of reverse engineering achieved by decapping integrated circuits and decoding their secrets by examining the raw silicon die. Few of us will have a go for ourselves, but that doesn’t stop the process being a fascinating one. Fortunately [Ryan Cornateanu] is on hand with a step-by-step description of his journey into the art of decapping, as he takes on what might seem an unlikely subject in the form of the CH340 USB to serial chip you’ll find on an Arduino Nano board.

Starting with hot sulphuric acid is probably not everyone’s idea of a day at the bench, but having used it to strip the epoxy from the CH340, he’s able to take a look under the microscope. This is no ordinary microscope but a metallurgists instrument designed to light the top of the sample from one side with polarised light. This allows him to identify an area of mask ROM and zoom in on the transistors that make each individual bit.

At this point the chemistry moves into the downright scary as he reaches for the hydrofluoric acid and has to use a PTFE container because HF is notorious for its voracious reactivity. This allows him to take away the interconnects and look at the transistor layer. He can then with a bit of computer vision processing help extract a bit layer map, which with some experimentation and guesswork can be manipulated into a firmware dump. Even then it’s not done, because he takes us into the world of disassembly of what is an unknown architecture. Definitely worth a read for the armchair chip enthusiast.

If you’re thirsty for more, of course we have to direct you towards the work of [Ken Shirriff].

Bringing Some Coulter To The Bench: Measuring Tiny Particles With Nanopore Sensing

March 22, 2021 by Adam Zeloof 6 Comments

We’ve all been there: you’re sitting at your bench, with a beaker full of some conductive fluid with a bunch of tiny particles suspended in it, and you want to measure the sizes of each particle.

Okay, maybe this isn’t a shared experience we’ve all had, but It’s at least an ordeal Hackaday alum [Nava Whiteford] has been through, and he was able to carry out the measurements in question using a neat apparatus known as a Coulter counter.

Imagine a container full of a conductive fluid. If you place an electrode at each end, the fluid will carry a current. Now, drop an insulating divider in the middle of the container, and the current will stop flowing. Finally, poke a small hole (or nanopore) in the divider. Huzzah! The current is flowing again… but how does this let us measure particle sizes? Well, now think about a tiny particle moving through the hole in the divider. As the particle passes through, the hole will be partially blocked, and the current flow will be partially interrupted. It turns out, the resulting dip in current is proportional to the volume of the particle — a fun property known as the Coulter principle.

[Nava] built a great demo of the system with a macropore in place of the nanopore. The pore in question was a hole melted into a bottle cap, which was suspended in a beaker by two toothpicks. [Nava] used small chips of Acrylic as the particles to be measured, which they pipetted into the solution of KCl. They then passed a current through the solution and used an oscilloscope to sense the interruptions. Be sure to check out their write up for a video of the system in action!

Of course, this technique has a much wider range of applications than measuring little bits of plastic — obtaining blood cell counts, for one. We’ve seen particle counters for use in the air before, but it’s great to see that there’s a way to measure particles in an aqueous solution — you know, in case we ever find ourselves in such a situation.

Battery Of The Future, Now Buildable Yourself

March 13, 2021 by Bryan Cockfield 9 Comments

In theory, batteries and capacitors are fairly simple. One stores energy chemically and the other stores energy in an electric field. In practice though, building an energy storage device that has a practical amount of energy density is delicate, complex work. But if you have access to a few chemical compounds it’s actually not too difficult to produce useful batteries and electrolytic capacitors with the use of ionic liquids.

Ionic liquids are conductive liquids with a few other important qualities. Almost all of the ones shown can be built with relatively common compounds, and most of the products have advantageous physical qualities, making them stable and relatively safe for use. With some equipment found in a chemistry lab it’s possible to produce a wide variety of these liquids without too much hassle (although one method outlined uses an inert gas chamber), and from there batteries and capacitors can be built by allowing the ionic liquids to be absorbed into the device.

The video below shows the production of several of these devices and then illustrates their effects by running a small LED light. While they’re probably not going to be used to create DIY electric cars anytime soon, the production and improvement of atypical energy storage devices will be the key to a large part of the energy needs of society now and into the future, especially aluminum batteries like these.

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Fueling With Ammonia

March 3, 2021 by Al Williams 68 Comments

There’s a major push now to find energy sources with smaller carbon footprints. The maritime shipping industry, according to IEEE Spectrum, is going towards ammonia. Burning ammonia produces no CO₂ and it isn’t hard to make. It doesn’t require special storage techniques as hydrogen does and it has ten times the energy density of a modern lithium-ion battery.

You can burn ammonia for internal combustion or use it in a fuel cell. However, there are two problems. First, no ships are currently using the fuel and second most ammonia today is made using a very carbon-intensive process. However it is possible to create “green” ammonia, and projects in Finland, Germany, and Norway are on schedule to start using ammonia-powered ships over the next couple of years.

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Ben Krasnow Measures Human Calorie Consumption By Collecting The “Output”

February 23, 2021 by Mike Szczys 37 Comments

It’s a bit icky reading between the lines on this one… but it’s a fascinating experiment! In his latest Applied Science video, [Ben Krasnow] tries to measure how efficient the human body is at getting energy from food by accurately measuring what he put in and what comes out of his body.

The jumping off point for this experiment is the calorie count on the back of food packaging. [Ben] touches on “bomb calorimetry” — the process of burning foodstuff in an oxygen-rich environment and measuring the heat given off to establish how much energy was present in the sample. But our bodies are flameless… can we really extract similar amounts of energy as these highly controlled combustion chambers? His solution is to measure his body’s intake by eating nothing but Soylent for a week, then subjects his body’s waste to the bomb calorimetry treatment to calculate how much energy was not absorbed during digestion. (He burned his poop for science, and made fun of some YouTubers at the same time.)

The test apparatus is a cool build — a chunk of pipe with an acrylic/glass laminated window that has a bicycle tire value for pressurization, a pressure gauge, and electrodes to spark the combustion using nichrome wire and cotton string. It’s shown above, burning a Goldfish® cracker but it’s not actually measuring the energy output as this is just a test run. The actual measurements call for the combustion chamber to be submerged in an insulated water bath so that the temperature change can be measured.

Now to the dirty bits. [Ben] collected fecal matter and freeze-dried it to ready it for the calorimeter. His preparation for the experiment included eating nothing but Soylent (a powdered foodstuff) to achieve an input baseline. The problem is that he measures the fecal matter to have about 75% of the calories per gram compared to the Soylent. Thinking on it, that’s not surprising as we know that dung must have a high caloric level — it burns and has been used throughout history as a source of warmth among other things. But the numbers don’t lead to an obvious conclusion and [Ben] doesn’t have the answer on why the measurements came out this way. In the YouTube comments [Bitluni] asks the question that was on our minds: how do you correlate the volume of the input and output? Is comparing 1g of Soylent to 1g of fecal matter a correct equivalency? Let us know what you think the comments below.

The science of poop is one of those 8th-grade giggle topics, but still totally fascinating. Two other examples that poop to mind are our recent sewage maceration infrastructure article and the science of teaching robot vacuums to detect pet waste.

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