Monday, May 30, 2022

Fractal Woodburning: Don't Try This At Home—Or Anywhere Else


Some topics are so intrinsically hazardous that one hesitates to write about them, on the off chance that someone who never heard about the subject before will get the idea to try it anyway, despite being warned not to.  I will compliment my readers by saying that you are all smart enough not to do that in this case.  But if you do, don't say you weren't warned.


The topic is something called "fractal woodburning."  Fractals are mathematical objects that show up in a variety of natural situations, from coastlines to lightning bolts to the lightning-shaped patterns called Lichtenberg figures, first described by Georg Lichtenberg, an 18th-century physicist who obtained them from early static-electricity generators.  Fractal woodburning amounts to creating Lichtenberg figures on the surface of wood. 


Now woodburning as a craft is a well-established hobby, and while it involves high enough temperatures to char wood, if the temperature is produced by a safely designed woodburning tool, the process is no more dangerous than using a soldering iron.  I've used soldering irons for almost sixty years and never started a fire with one or seriously injured myself, so nothing in this column should be taken as a criticism of conventional woodburning.


But fractal woodburning is another matter altogether.  An Internet search reveals that the typical fractal woodburner, assuming he has survived, has disassembled an old microwave oven to obtain the transformer.  Then he took a piece of wood and soaked it in a conductive solution such as salt water.  Then he connected one wire from the transformer to the wood and plugged the transformer into a wall socket.  He then held the other wire somehow and touched it to the piece of wood, whereupon a spark jumped around on the wood surface and made a pretty fractal pattern, if he was lucky.


If he's not so lucky, one or more of a number of things can go wrong:


1.  The wood can catch fire.  It has to burn some anyway to make the pattern, and wood has a nasty habit of just burning up completely despite the artist's intentions for it to do otherwise.  This fire can spread to the table, the floor, the ceiling, and end up totalling your house.


2.  Even more exciting, the insulation (if any) between the burning wire and the person holding it can break down.  Microwave oven transformers put out about 2,000 volts AC at a peak current of several amps, which is just about exactly the power used in electric chairs (they also use salt water to improve conductivity through the skin).  Yes, a person with a fractal woodburning set has made their own homebrew electric chair without knowing it.  The American Association of Woodturners has a list on their website of 34 people, names and dates included, who have died while trying to do fractal woodburning.  That's more than the number of people who have been executed by means of the electric chair in the U. S. since 2015.  And none of those people doing the fractal woodburning had done anything deserving of death that I know of, but it caught up with them anyway.


3.  You may actually avoid the first two hazards and live to show your fractal woodburning efforts to others, thus attracting them to this deadly hobby.  In a way, this is a worse outcome than the first two, because burning your house down or dying as a result of fractal woodburning is pretty well guaranteed to turn you off from the hobby and keep others away from it too.  Whereas, a successful effort is likely to give you the faulty impression that there's nothing dangerous about it, and you'll want to get others involved, to their peril. 


During COVID-19, a lot of people had more time on their hands than usual, and perhaps fractal woodburning got a boost when bored individuals stumbled across it on the Internet.  It's hard to imagine such a practice getting established without the Internet, because no brick-and-mortar store or responsible publisher of hard-copy materials—in other words, nobody with anything substantial to lose—would promote or endorse such a dangerous pastime, for fear of getting their socks sued off.  But our ultra-democratic Internet lets anyone who can type and do stupid things tell others about how they got away with it, and so you end up with the phenomenon of fractal woodburning.


Can fractal woodburning be done safely?  I don't see how.  I've gotten to be an old electrical engineer by being very careful around high voltages.  I will admit to having disassembled a microwave oven for purposes other than those for which it was designed, but the piece of lab equipment I built with it was protected with interlock switches and other safety features.  Nevertheless, it did cause a fire inside a metal test chamber.  To put out the fire, I was obliged to use a dry-chemical fire extinguisher on it, and we spent the next two days cleaning up after that little incident. 


If you are just dying to have something pretty and fractal to look at, there are responsible outfits such as Captured Lightning ( which use electron-beam equipment (behind layers of lead and concrete shielding) to create beautiful lightning-like patterns in acrylic plastic blocks.  True, you can't say you made it yourself, but at least you're still around to show it to other people. 


There are those who would say we should suppress information on the Internet that is so dangerous there's no way people can do it safely, including websites that encourage folks to try fractal woodburning.  I'm not sure I would go that far.  After all, there are many dangerous and foolish things people can do with their time, and at some point you have to assume folks will just use common sense.  By now there are at least as many warnings out there against fractal woodburning as there are sites promoting it, and only the most determined self-immolators are going to ignore all the good advice out there against fooling with it (now including this blog) and try it anyway. 


Sources:  I referred to an article in the Washington Post about a couple in Wisconsin who electrocuted themselves and burned their house down with fractal woodburning at  The American Association of Woodturners warns against fractal woodburning at  Information about the power supply to electric chairs is from, and statistics on deaths by execution are at  Texas does not use the electric chair, or else the numbers would be even higher. 

Monday, May 23, 2022

Driver of Tesla on Autosteer Charged with Vehicular Manslaughter


Shortly after the first commercially available driver-assist autopilot-equipped vehicles appeared on roadways, pundits raised the question of who would be responsible in case of an accident:  the driver, the vehicle maker, or both?  That question is about to get legs in the case of Kevin George Aziz Riad, who prosecutors have charged with two counts of vehicular manslaughter as a result of an accident that occurred on Dec. 29, 2019 in Gardena, California.


As we described the crash in this space shortly after it occurred, a couple in a Honda Civic were making a left turn at an intersection with the terminus of the Gardena Freeway that evening.  The traffic light at the intersection was green for them, and red for oncoming traffic to their right coming off the freeway.  Neither Riad nor the Tesla Model S he was driving paid any attention to the numerous slow-down signs or the red traffic signal when the Tesla barreled at 74 MPH into the Civic, killing both of its occupants and slightly injuring Riad and his passenger. 


Subsequent investigation proved that the Tesla had both Autosteer and Traffic Aware Cruise Control engaged at the time.  Tesla's instructions to drivers using these features are clear:  the driver must keep a hand on the steering wheel at all times and "be prepared to take over at any moment."  The Gardena Freeway is basically straight for at least five or six miles before its termination, and data recovered from the Tesla showed that Riad had not moved the steering wheel significantly nor applied the brakes for six minutes before the crash. 


Riad's defense attorney asked Los Angeles County Superior Court Judge Teresa Magno to lower the charges to misdemeanors, claiming that if a crash hadn't occurred the worst charges would have resulted from just running a red light.  The judge declined to follow that line of reasoning, and instead ruled that the trial for vehicular manslaughter will proceed.  It is widely believed that this is the first such trial involving a commercial version of automated driving technology, according to a report in the Orange County Register and a subsequent AP story.


Car accidents due to inattention are nothing new, but the novel feature of this case is that technology has allowed inattention to soar to new heights. 


In the days before driver-assist technologies such as autosteer and cruise control, one of the chief dangers of a long, straight, dull stretch of freeway was that a fatigued driver might simply fall asleep from monotony.  I'm sure this has happened to most drivers at least once or twice, and most of the time, the consequences are minor:  a slight drifting from one's lane, a jerk awake once you realize you've been dozing, and a quick flurry of attention to get things back on track.  If a fatal crash results, then the prospect of vehicular homicide charges arise, and while juries may be sympathetic to someone who simply falls asleep at the wheel, part of driving responsibly is knowing not to drive when you're very sleepy, and it's reasonable to charge such people and sometimes convict them of negligent homicide.


With the sophisticated driver-assist technologies of cars such as Tesla's Model S, the driver receives mixed messages.  According to an article in Popular Science, the Society of Automotive Engineers has established a five-level system for assessing how self-driving a self-driving car is, and the Model S features get it only to Level 2.  In Level 2, the driver is still in charge, even though the system can automatically brake, accelerate, and steer.  But according to Popular Science, that is not the impression that Tesla gives many of its drivers, who apparently play chicken with the system to see what they can get away with, keeping one hand on the steering wheel but having their attention otherwise engaged for many seconds or minutes, as Mr. Riad apparently did. 


And despite the efforts of Tesla engineers to prevent this kind of thing, they have not yet developed a psychic feature that reads the driver's mind in order to find out if he or she is really paying attention, or just acting like it with one hand on the wheel and the rest of the body doing something else altogether.  The number of fatal crashes involving Teslas with some form of driver assist engaged has reached the point that the National Highway Traffic Safety Administration (NHTSA) has required automakers to report any crashes on public roads involving such systems, including vehicles from Tesla and those of several other firms. 


While the absolute number of fatalities in such crashes is small, they form a leading edge of a worrisome upward trend in auto casualties generally.  After reaching a minimum in 2011, the number of U. S. auto fatalities has been creeping upward from less than 33,000 in that year to 38,824 in 2020.  A significant number of these crashes have been linked to inattentive driving in which technology—smartphones, videos, and driver-assist devices, among others—was a factor.


As driver-assist technology is only going to get more widespread as the cost declines and the performance increases, it's even more important that we figure out how to manage the transition between complete driver responsibility, in which nothing automated intervenes between the driver and the road and the driver recognizes that—and complete irresponsibility, the sought-for SAE Level 5 in which the car harbors an effective ideal chauffeur who allows the passengers to play pinochle, sleep, or do whatever else they want during the completely programmed ride. 


No Level 5 technology currently exists outside laboratories and highly-controlled environments, and it is far from clear that we will ever get there unless some radical changes are made in our entire approach to automotive transport.  In the meantime, we have to figure out a way to keep things like the Gardena crash from occurring.  Prevention may have to take the form of really annoying features such as having to press a button whenever a random light blinks, or something along those lines.  Although it would go against the grain of the Tesla-style "Look, Ma, no hands!" approach, we as a society will have to evaluate how much we want to save lives at the price of a little inconvenience.


Sources:  The AP story on Judge Magno's ruling to proceed to trial was carried in numerous places including ABC News at  I also referred to an article in the Orange County Register at, and used the sites

and well.  My first blog on this incident is at

Monday, May 16, 2022

What Tom Brady and I Have In Common


Tom Brady, as every sentient resident of the U. S. probably knows, is widely regarded as the greatest football quarterback of all time.  But even that track record didn't help him the other day when he decided to rent a Citi Bike in New York City and ride a few blocks, subsequently posting his experience on his widely-followed Twitter account, where the New York Post found it and wrote it up. 


Here's where he and I shared a common experience.  By his own admission, he hadn't ridden a bicycle in New York for about fifteen years.  When he went up to the self-operated kiosk to unlock a rental bike, Brady says it took him about ten minutes to figure out how to unlock the thing.  I, too, have recently decided to rent a bike from a self-service kiosk for the first time.  And I, too, had a heck of a time getting it unlocked, though perhaps for different reasons than Brady had.  Beyond this single commonality, I don't think Brady and I share much else.  But the fact that someone as otherwise physically competent as Tom Brady had that much trouble figuring out how to rent a bike may say something about the systems used. 


Because I naturally have more first-hand knowledge of my experience, I'll summarize it briefly here.  I still have relatives in Fort Worth, Texas, where I visit occasionally, and last month I was in town staying with my sister and had some extra time on a Saturday afternoon.  The last time I'd been in town, I had noticed some bike-rental kiosks on the bank of the Trinity River, where the city has installed jogging and biking trails that follow the river for many miles.  So I looked up on the web where you could rent a bike at a location I knew how to access by car, paid online for a one-hour pass (eight bucks), and headed down to the kiosk without any clear knowledge of how they were going to know I paid for it.


I should mention at this point that, in contrast to Tom Brady and most other adults in modern civilization, I do not have a smart phone.  Well, I sort of do, but it's what you might call brain-damaged.  It's a flip phone sold by the Caterpillar Tractor people, I suppose on the basis that if there is still any market for rugged flip phones, people in the heavy-equipment industry are liable to be a big part of that. 


I don't spend a lot of time around heavy equipment, but when my telecomm company forced me to get rid of my old flip phone a few months ago because it would no longer work with their upgraded 5G system, I hunted around and found the one new flip phone out there, and got that.  It's basically an Android system, but the little screen makes most standard apps either inoperable or impractical, and I haven't bothered with installing any of them anyway, because that's not what I want the phone for.  So I can make phone calls, I can text after a fashion, but that's about it.  And that's all I want from my flip phone, which I don't have to worry about dropping on the floor.


Fortunately, the people who designed the bike-rental kiosk had taken into account eccentrics like me who, for whatever reason, chose not to download the rental app on their smartphone.  At the end of the kiosk there was a box with a touchscreen, and a place where I could enter personal details like my phone number.  The idea was, they'd text me a confirmation number to check that it was me, and then when that matched my paid-up account, the system would unlock the bike.


Most of the bikes had electric assist, which wasn't something I was familiar with, so I picked the one bike on the rack that was just a plain old manual bike, and started to try to rent it. 


At this remove, I don't recall all the details, but I ran into several problems. 


One was, the surface of the touchscreen was very weathered.  This both made it hard to read in the sunlight, and it also failed to register my touches unless I pounded two or three times in the right place, which wasn't easy.  So it took the better part of a minute just to enter a four-digit number, what with all the mistakes and not-registering and all.


Eventually, I got through the rigmarole that a non-phone-app-user had to get through, and I heard a click.  I pulled my selected bike out from the rack, only to discover that it had a flat.


So here we went again:  put it back, make sure the machine recognizes I finished my world's record short bike ride, make sure I still had some of my eight dollars' worth of riding left, and start all over with the phone number entry, the text to my phone, the punching in of the new text code, etc. etc.  This time I grabbed the first bike that didn't look like it had a flat.  I tried the electric assist but never could get it to do anything.  No matter—I'd come out for the exercise anyway.


The bike ride itself was uneventful, and I made it about halfway to Benbrook before turning around at a point where I would have had to cross the river over a kind of spillway.  The battery made the electric-assist bike a little heavier than it would have been otherwise, but it had three manual gears too, which was all I needed for the gentle rises on the path.


Once Tom Brady finally managed to free a bike, his ride was uneventful too, although as a safety issue I feel compelled to mention that he failed to wear a helmet. (I'd borrowed my sister's helmet on my ride.)  Imagine the headlines if he'd fallen off:  "All-time-greatest quarterback felled by rough spot on Broadway pavement." 


Fortunately, neither Brady nor I encountered anything worse on our bike rides than a less-than-friendly user interface.  But we both eventually got our bikes, and I suppose that is some sort of success.


Sources:  Tom Brady's bicycle excursion around New York is written up at 

Monday, May 09, 2022

Is Cryptocurrency the Future of Money?


The Silicon-Valley firm Nvidia recently got in trouble with the SEC for not disclosing that a good bit of its profits in 2018 were due to sales of their graphics processing units to cryptominers.  Cryptominers verify cryptocurrency transactions in operations that take a vast amount of computing power, real electrical power, and cooling.  One estimate quoted in a recent Associated Press story says that cryptominers making Bitcoin, only one of several types of cryptocurrency, use up 0.2% of the world's electrical supply. 


The reason the SEC fined Nvidia $5.5 million was that cryptocurrency, and presumably the cryptomining that goes along with it, is notoriously volatile.  In the SEC's judgment, Nvidia should have told its investors that a lot of their 2018 profits came fron the up-and-down business of cryptomining.


For a firm with $26 billion in revenue, $5.5 million is chump change, and most of the damage to Nvidia was already done once the press releases came out.  But the SEC's action bespeaks a larger prevalent attitude that government institutions, at least in the U. S., have toward cryptocurrency.  If a company can get in trouble merely for selling their products to cryptominers and not telling their investors about it, the SEC must be really down on cryptocurrency.


And this is not a surprise.  Whoever came up with the idea of Bitcoin in 2008 clearly wanted to leave governments and their meddling with currency behind.  In a sense, cryptocurrency is a libertarian's dream:  nobody controls it and nobody can do Federal-Reserve-type manipulations to it or attempt to tie it to any particular conventional currency.  A unit of cryptocurrency is worth exactly what people will pay for it—no more and no less.


In retrospect (Monday-morning quarterbacks are always right), it was almost foreordained that the few lucky people who bought bitcoins and other cryptocurrencies as they were issued ended up making fantastic profits, at least on paper (or bits).  But after the first cryptocurrency-rush days, the crypto market turned into something resembling the futures market for hog bellies,  but without the inconvenience of having to keep a lot of smelly hog bellies around.


And unlike hog bellies, cryptocurrency uses a lot of energy, much of which is generated with fossil fuels that increase the globe's burden of carbon dioxide.  That bothers some people more than others, but it is a definite downside to cryptocurrency compared to more conventional media of exchange.


Another factor that gives cryptocurrency a somewhat shady reputation is that it has proved very popular with international criminals.  An untraceable, serial-number-free virtual currency is just what the drug dealers and online extortionists like to use, and many of these types will not accept any other kind of money.  (I'm told this—I've never tried to pay a drug dealer myself, either with cryptocurrency or cash.)


So with those counts against it, one shouldn't be too surprised that although cryptocurrency has been accepted in certain circles and by at least one government as legal tender (El Salvador), its progress is slow.


While some may view the advance of cryptocurrency as progress, in some ways it marks a return to a system that prevailed in the early and mid-19th century in the U. S.  While the U. S. government (and the Confederacy during the Civil War) issued its own currency, many private banks chartered by state governments also issued their own currency.  In a given locality, you might have businesses trading in three or four different kinds of money, and so someone would have to keep an exchange chart stating what their comparative worths were. 


And volatility was also an inevitable consequence of that system.  Private banks could flood the market with bills or even go broke, rendering the currency they issued worthless.  In a time before the telegraph had penetrated to most parts of the U. S., a store might take in payment a bunch of bills issued by the Pawtucket State Bank of North Carolina, only to learn a few days later that the bank had ceased to exist.


Of course, all paper money back then was exchangeable at some rate with gold, which was the main medium of monetary exchange between governments.  There are stories of one company loading a ton or so of gold bullion onto a ship at Port A bound for Port B, and another company loading a ton of gold onto a ship in Port B bound for Port A.  Besides being downright silly, such mechanical exchanges were prone to the hazards of ocean travel.  If one of your ships went down with your gold bullion, you were out of luck.


That can't happen with bitcoin, but it can certainly "sink" metaphorically, and has numerous times, wiping out value just as effectively as if it was a pile of gold bars going down to Davy Jones's locker.  As long as cryptocurrency developers insist on staying independent of government control, it seems like volatility will be part of the game.  And that means only people who like to take lots of risks anyway (e. g. drug dealers and online shakedown artists) will accept the risk of volatility for the anonymity and other advantages cryptocurrency has for their business models, if we can call them that.


Three years ago, Facebook launched its own version of cryptocurrency, then called Libra.  Originally, they tried to tie it to a basket of currencies, but regulators nixed that idea.  Then it was rebranded as Diem, and tied to the dollar, but reportedly the Federal Reserve pressured the bank involved to cut its ties with the organization, thus dooming it.  If a substantial outfit like Facebook can't launch a modified cryptocurrency that has some promise to maintain a stable value, it looks like nobody else will try any time soon. 


So for the foreseeable future, all five minutes of it, cryptocurrency looks like it will remain a fringe enterprise, enjoyed by a few rich risk-takers, disappointing others who buy it at the wrong time, and having a core constituency of users whose characters are dubious, to say the least. 


Sources:  The AP story about Nvidia's fine by the SEC appeared in numerous outlets, including the Sacramento Bee at  A report on the fate of Facebook's Libra can be found at  I also referred to Wikipedia articles on Nvidia and cryptocurrency.  My blog on Libra when it came out in 2019 is at

Monday, May 02, 2022

Finding Drones in Peace and War


DJI, the world's largest drone maker, has announced that it is stopping all shipments of new products to both Ukraine and Russia.  The Verge reported this on Apr. 27 following earlier stories that Russian troops were using a drone-tracking technology called AeroScope to locate Ukrainian drone pilots flying commercial drones that had been converted to combat use.  And last week, the White House announced that it was asking Congress to pass laws making it easier for government agencies to detect and track drones.


Drones, more formally known as unmanned aircraft systems (UAS), have changed from super-expensive military-only devices a couple of decades ago into popular consumer and professional products today.  Advances in software and hardware have led to over two million drone users in the U. S. alone, and the repurposing of consumer drones for military uses both by guerilla groups and defenders of the Ukraine. 


Most drones are not autonomous, but controlled from the ground by means of a radio link.  The radio link is the means by which both the controller and other parties can locate and track the drone.  In anticipation of the time when radio identification of drones would become a government requirement, in 2017 DJI began to include a signal broadcast from every drone they made which provides the drone's "position, altitude, speed, direction, serial number, and the location of the pilot."  This data is unencrypted, meaning that anyone with the proper receiver can pick it up. 


DJI also conveniently made available a system called AeroScope, which can receive this data and provide a readout of all drone locations within distances of a few kilometers, depending on the type of system.  Up to now, DJI has sold AeroScope only to law-enforcement agencies and other entities that it deems appropriate for the technology. 


Confirming DJI's intuition, in 2020 the U. S. FAA issued regulations that make it mandatory for any drone weighing more than 0.25 kilograms (about half a pound) to broadcast its location, the operator's location, and an identifying number by 2023.  So by next year, all drones big enough to do anything other than entertain the owner will have to have such radio identification means, whether they are new or old.


As an ethics issue, the question of drone identification and location technology has a number of ramifications.  From the Wild-West days when consumer drones were too rare for the FAA to have made detailed regulations, we have now reached the point that drones of any size must be trackable by authorities. 


If drone users aren't doing anything nefarious, it's hard to imagine why they would object to the requirement that drones must broadcast their identity and location.  A useful comparison might be made to automobile license plates.  The first state to issue state-made automotive license plates was Massachusetts, back in 1910.  Most automobile owners back then were glad that the states began to register and license their vehicles, because it freed them from having to follow a hodge-podge of local regulations that often put them at a disadvantage with respect to horse-drawn vehicles legally.  Massachusetts started their early license-plate numbers with 1 and went up from there.  I don't know if this is still the case today, but up to 1999 (the last year I lived in the state), it was possible to will one's legacy two-to-four-digit license plate to one's heirs, so that your low license-plate number let everybody know that your ancestors were among the first thousand or so people to own a car in Massachusetts. 


I doubt that any drone owners are going to get so attached to their drone ID numbers.  But there are real privacy and security issues in the question of who can access the drone ID signals.  Because DJI has not encrypted the data up to now, the company's AeroScope is simply a convenient way for a law-enforcement agency to get into the business.  I suspect that any well-informed engineer could come up with a similar system by combining the suitable microwave receivers with decoding equipment that would not have to be fancy at all. 


The White House's initiative seems aimed at giving more government entities permission to do this kind of snooping, and providing them with a list of approved equipment that does so.  There is an opportunity here for entrepreneurs to get in on the ground floor of drone-detection equipment, assuming that Congress responds, but that is an open question.


What is not in question anymore is whether a drone operator can fly with the assurance that nobody can find out whose drone it is or where he is.  That assurance, if it was ever present, is now gone.  And in the vast majority of legitimate-use cases, this can only be an asset to the situation.


As for Ukrainian drones, one must applaud the ingenuity of those who repurposed commercial and amateur drones for military purposes, either for surveillance or actual delivery of weapons.  At the same time, it's not at all surprising that the Russians would use AeroScope or something similar to track down the drone operators and attack them, although at this writing it is not clear whether this has actually happened.  One does not see license plates on tanks, and so the requirements of wartime use for drones are very different. 


Drones originated to meet wartime needs, and it's likely that the U. S. or other allied countries can supply Ukraine with military-type drones that will be far more effective than repurposed hobby-type units. 


Whenever I bring up the subject of engineering ethics in a discussion, if it goes on long enough sooner or later someone will come up with the bromide, "Technology is neutral—it's only how it's used that's good or bad." 


Like many sayings, this one has an element of truth in it.  But anonymized drones are obviously more suited to warlike uses than ones that constantly announce both their position and the position of the operator.  So the cases of drone identification in peace and war shows that this saying is limited in its applicability, to say the least. 


Sources:  The Verge carried articles I referred to on various aspects of drones and AeroScope at and   A summary of the White House initiative is at  The FAA's new drone ID requirements are found at  And the story about the first automotive license plates in the U. S. is from