An Introduction to Feedback Systems

I plan to talk more about technical topics in the coming weeks, and one of those topics that's worth covering is an introduction to Control Systems, commonly called Feedback and Control Systems. 

I know that some of you are already really familiar with these things, in great and gory details.  Take the night off (unless you care to look for mistakes to correct).  For my career in radio design, I principally designed feedback and control systems like Frequency Synthesizers (Phase Locked Loops - PLLs), Automatic Gain Control (AGC) systems in receivers, Automatic Level Controls (ALC) for transmitters, and Cartesian Transmitter Linearizers.  For those of you who haven't looked into the subject, electrical engineering students take a class in control systems that tends to be a very analytical and very mathematical.  I'm going to skip the math and try to explain things in words.  I'll also be the first to say that when you design your 10th or 15th PLL or AGC, there's not much theory involved.  It's pretty much you just solve a few equations (which you've probably stuck in a spreadsheet or other software) and you're done.

For starters, let's define a feedback system.  It's a system that corrects itself by comparing its state ("what we got") to its desired state ("what we want it to be").  This diagram is a simple type of feedback system.

For some folks, this is probably more confusing than helpful, so let's do a simple example of something that everyone knows: a thermostat in an air conditioner.  The thing we're controlling is the temperature at the thermostat, which we use as a proxy for the temperature everywhere under that air conditioning.  The feedback sampler is a thermocouple or something that measures the temperature - the equivalent of a thermometer.  The heart of the loop is that circle with an X in it, which acts to compare the "what we want it to be" (the thermostat setting) to "what we actually got".  It compares the two electrical signals and generates an error signal ("what we got" minus "what we wanted") that goes to something called the feedback controller here and that makes the feedback correction.  In a thermostat, this is an on/off switch.   

It's important to notice that if the output is bigger than we wanted, the control system turns it down, and if it's smaller, the system turns it up.  Since the correction is opposite the measurement, this is called negative feedback.  If you think of the audio screams and howls that happen when a microphone is in front of a loudspeaker, there is no correction and the output gets louder until it can't go up any more.  This is a type of positive feedback, not a control system.  Perhaps you've heard of the term vicious cycle, where something happens and its result is to contribute to causing it again: that's a positive feedback situation.

What I'm going to describe next is how my central air conditioner works.  I don't know how universal this is, but I've watched my thermostat and know that if I set some temperature, say to cool the house to 75 degrees, it won't turn the air conditioner on to reduce temperature until it measures 2 degrees above the desired temperature, 77.  The error has to be that big before it will turn on.  The air conditioner then comes on at full power until the temperature at the thermostat reaches the desired temperature, sometimes it overshoots and goes a degree lower than the thermostat is set.  There has to be some sort of difference (called hysteresis) in the temperature between when its' getting warmer and when it's getting cooler.  There's no way the system could know to both turn on and turn off when it's 75.

This is what's called a Bang-Bang controller.  It either turns on the cooling 100% or it turns it off (0%).  That's a pretty crude system, and lots of control systems you're familiar with don't work that way.  Consider cruise control in a car: if you had a Bang-Bang controller your accelerator would go full throttle or to idle.  A Bang-Bang controller works for a simple thermostat, but in a cruise control the demands for accuracy are higher, and we want something that doesn't continually speed you up and slow you down by a couple of MPH. 

There are much more elegant control systems available, and the smoothest response is generally the Proportional-Integral-Derivative or PID controller.   A PID controller calculates three quantities and then combines them to create the error correction needed.  Hopefully, this graph will help explain it while I add some words.

Proportional to error means that the bigger the error, the harder it tries to correct.  Integration of errors over time is an averaging process - it means that the result is incorporating both how big the error is and how long it lasted; its output gets bigger if some error has lasted longer, not just if the error is larger.  Finally, Proportional to the rate of change term is determining if the error has gotten larger quickly or slowly. 

The drawback of PID systems is that they're complex and can be hard to get running well; in many cases, an error signal that's proportional to the error is all that's needed.  I don't recall ever seeing an AGC, PLL, ALC or any other electronic control system that used a PID controller.  On the other hand, this is something that the continuing advancement of electronics has vastly improved, and for some control tasks, like the temperature of furnace, kiln or for some operation, you can buy a preprogrammed, ready-to-use PID controller for well under $100, and sometimes under $20. 

Proportional or PID systems are starting to make their way into air conditioners.  We have a Mini Split system in the workshop and it behaves that way.  Instead of the unit turning off when the temperature is cooler than the thermostat is set for, it cools at the lowest energy consumption it can. 

A Fun Fact is that PID controllers were first developed for automatic steering systems of ships at sea in the 1920s.  They make an obvious choice for automatic steering systems in an autonomous car or truck.  The details of how the car decides "what we want" and measures "what we got" are monstrously huge problem that have to be solved. 

This Guy Needs a Little Econ 101

Cartoonist Bob Gorrell:

Once more from the top.  Corporations do not pay tax.  Corporations collect tax.  Since the bulk of their sales is to middle class people (because they're the majority of the country), the middle class taxpayers pay the corporations' taxes.  Corporate tax cuts are middle class tax cuts. 

Corporations don't have a penny that wasn't made through sales.  Consider a local "mom and pop" pizza parlor.  Their sales price consists of two major things:

• Cost of materials and the labor to make it sellable (for example, pizza ingredients plus the labor to make them into that delectable Food of the Gods) 
• Overhead (for example, electricity for the oven, rent for the building, napkins, other supplies, and taxes/fees mandated by the various government levels that regulate.  Things like insurance payments for workman's compensation, unemployment insurance and an increasingly longer list of fees/taxes.) 

Those are absolutely mandatory expenses that must be covered.  Maybe not minute by minute, but if those expenses aren't covered, the business can't survive. 

Whatever rate the Feds tax at, that's before profit and part of what must covered by price.  That tax is paid by the pizza buyer.  If the percentage of taxes drops, the price of the product can drop, or it can leave more money in the business for expansion.  Ultimately, both of those outcomes are good for the pizza buyer.

Veteran's Day Tribute 2017

There really isn't anything I can add to the quality writing exhibited around the blogs today.  I came of military age while the Viet Nam war was winding down and the draft switched over to a lottery system.  My number was high enough that they didn't get to me that year, and because no one in my family had a history of enlisting, it simply never occurred to me.  I had one friend who went to the Air Force Academy, but that just seemed different.  So while I'm not a veteran, I have deep respect for those of you who are.  You allow me to sit here and write this. 

There's a million good images to use, but this one speaks to me.

Extreme Modeling

A few weeks ago, when I wrote about the new Blade Runner 2049 movie, I emphasized the virtual world they created.

It may be the most visually stunning movie I've ever seen.  The design of the futuristic dystopian world they create is really incredible.  It's literally world creating, not set creating.  The sets - however much is CGI and how much is carpentry and paint I can't say - are simply amazing.

Today I stumbled across a bit more information on this.  The 3D CAD program I use the most, Rhino3D, has a user forum that I visit perhaps once a week.  Today, someone pointed out that in this video, there's evidence that Rhino was used in the creation of the world of Blade Runner.  Sure enough, there's a brief glimpse of a computer screen with program menus at 53 seconds in this video.  I doubt it lasts a half second.  It could well be Rhino, but I'm not familiar enough with other tools to know that it's the only program it could be.


Whether it's Rhino isn't the point of this post.  The point is a look behind the scenes at the utterly amazing models they built.  Then notice the sheer number of artists and model builders that they employed.  Notice their incredible attention to detail.  Not to mention the physical size of these models.  There's a spot in the video (around 3:10) where production manager Pamela Harvey-White says of one set of models, "they're "bigature", not miniature.  They're just massive buildings".

Honestly, I didn't know this sort of "movie magic" was still done these days.  I can never tell anymore whether I'm looking at actors in front of a green screen with everything drawn in around them, or how much of the set is really there.  I mean, if it's like Guardians of the Galaxy and someone is talking to Rocket the talking Racoon, that one's pretty obvious.  How much of the rest of the scene is there? 

 One of the commenters on the Rhino Forum says

Actors have a really hard time relating emotionally to a story in greenrooms, acting with placeholders in greensuits, so the trend is to let them have as much real scenery around them as possible. And the same goes for directors and photographers, it is much easier to be in the scene with a miniature as you can light it and tweak it hands on, instead of having to ask a “teenager” if “this” or “that” is possible.

Everyone talks about AI and Robots taking over everything, right?  Are they going to imagine scenes like these or the virtual world of Blade Runner?  I'll believe it when I see it.

So let me leave you with this fun fact: the actor in full body makeup with his hand on the greensuit guy sitting for Rocket is David Bautista.  He's in the opening scene of Blade Runner 2049.

The First Actual Chainsaw Bayonet

I was sure I still had this picture, but I had to go do an image search to find it.  The actual chainsaw bayonet.

OK, maybe it's not the actual first chainsaw bayonet; it's just the first picture I ever saw.  I thought I had it on my computer, but I searched pretty extensively and couldn't find it.  Must have said, "I'll never need that picture again" during one of my cleanup frenzies.

Hat tip to MRCTV - the Media Research Center - which includes cringe-inducing video of the saw in action and this chainsaw carrying assault junk Huffy bike.

While Searching for my Next Engine to Build

I came across an interesting post on Pinterest: a Stirling engine-driven battery charger. 

If you haven't already noticed, that's a rendering of a 3D model, not a photo of an engine, and when I went to the original source, Interesting Engineering, it became apparent it's vaporware.  The original rendering and short little article was by a three Mechanical Engineering students who graduated before building this. So no plans and no numbers to understand the problem.

Stirling engines are nothing new, Scottish Clergyman Robert Stirling invented the concept in 1816, and they're very popular among home machinists.  Stirling engines are heat engines that operate by cyclically compressing and expanding air - a good explanation here and a good animation of how they work here.  A well built Stirling engine can turn a good sized fan blade, or spin some sort of flywheel.  There are models which will work on the warmth from your hand. 

I can find that a well built Stirling should achieve efficiency around 66%, but what I can't find is how to design it or how big it needs to be (physically) to deliver a desired amount of power.  In this application, you know that USB chargers are typically either 5W or 10W.  In my mind, that tells me if I want the engine to charge things at the 10W level, it needs to be sized to put out more than that.  How much more?  Since there will probably be some inefficiencies in the circuitry, lets say the generating system is 75% efficient, that means the input to the generator needs to be 10/.75 =  13.3W and the input to the engine would need to be 13.3/.66 = 20.2W.  To me, that ought to be how the size of the flywheel and the piston are calculated.

There's a handful of videos that pop up on YouTube of folks using Stirling engines as phone chargers. I don't know that they're honestly 20W charge rates, but some folks are claiming nearly that. Time for a little more research. 

A Little Update on Son of Side Project

I don't want to jinx myself, but I could be getting into the last little bit of the project I call Son of Side Project; adding a wood side to my Breedlove demo guitar that was introduced to Mr. Bandsaw and hasn't been complete in perhaps a decade.

In that last update, I had gotten to the point where I was ready to glue on the internal wood strips (kerfing strips) that would hold the side.  I eventually got those glued in place.  I had some issues with a couple of pieces of it shifting before the glue would hold it.  As a result, I had to learn how to loosen fish glue and re-stick the pieces.  I replaced one.

Once the side was glued on, I took it down to my friend who has a fixture designed for routing the top of the guitar to add the trim binding strips.  The fixture uses a small, trim router and ball bearing collars to allow an exact width and depth channel to be cut.

This is how I brought it back last Wednesday.  There was an unfinished end like that on the front and back of the guitar where we didn't push the router too far.  So how to cut those off and extend the channel the rest of the way?

Rather than try to do this with power tools, like the rest of the channel for the binding, I went for hand shaping the wood.  I clamped a piece of wood to the top of the guitar as a guide and used a 1/4" wide woodworking chisel.  I cut straight vertically leaning the chisel against the guide to form the back wall of the channel.  The flat back of the chisel would form the new back, and I pushed the chisel in a little at a time (no hammer!), then went in parallel to the top from the side taking out small chips to remove the spruce I had just scored with vertical cuts.  It's a lot like chiseling out the waste in a dovetail joint, parts of a mortise, or pretty much anything. 

This picture is preliminary, before I finished cleaning up the channel, and it's magnified much more than I was seeing with Optivisors on (which is why I took the pic).  That step from top to the floor of the channel is 1/16".

Then it was time to start gluing up strips to try and match the colored strips you see in cross section in the corner.  I've done this a couple of strips at a time, and now have that top strip in place. 

The tape is in place as a "clamp" for 12 hours, so I can take it off in the morning.  There's a mess of to cleanup here, and some gaps that need to be filled with something or other.  The sides and back trim need to be done as well, but that will be simple compared to this top strip. 

Like I say, I don't want to jinx myself, but I'm making progress. 

Thor Ragnarok - Tons of Light Hearted Fun

I've been looking forward to seeing Thor: Ragnarok, the latest installment in the Marvel Cinematic Universe and third Thor installment since the first trailers started leaking out last April.  It looked like it was going to be fun and it turns out that's an understatement.  Aside from the very, very rare comedy that leaves me laughing until my sides hurt, I don't think I've laughed as much at a movie. 

The name, simply pronounced rag - na - rock, is the mythical end of days for Asgard, the kingdom Thor is from.  The movie, then, is about the apocalypse, and is done extraordinarily light-hearted, which is probably a good way to handle the End of Days, ("it's the end of the world and I feel fine").  There are one or two light-hearted scenes in the trailers - the big one at the end with Thor recognizing the Hulk, whom he's supposed to fight to the death, and breaking out in a smile shouting "We know each other!  He's a friend from work!"  The first scene in the trailer is shown as deathly serious, but actually isn't that way in the movie.  Something that stood out in my mind was the scene in that trailer that features actress Cate Blanchett as Hela, the Goddess of Death and the villain of the movie.  The scene was changed from the first way we saw it. 

In the first trailer, this scene takes place in what looks like a big city alleyway.  In the movie, this takes place in an open green field (as you can see), which is supposed to be in Norway.  Thor hurls his hammer at her, which is supposed to be impossible for anyone not pure enough of heart to lift, and she not only catches it one handed, she destroys it.

Besides the regulars of Chris Hemsworth as Thor, Tom Hiddleston as Loki and others you'll know if you've seen the first two, the move features Blanchett (who seems to be a very versatile actress), Jeff Goldblum who is masterful playing some rather eccentric people.  Probably the only bow to political correctness is making Tessa Thompson, who's apparently a small, African American woman, the Valkyrie.  Valkyries are from Norse mythology (as is the whole Thor universe) and usually depicted as tall, blond, Norse women.  Ignoring that, Thompson does well in the part.

Y'all know I'm a fan of these light, comic book fantasy movies, but I give this a full five stars and am even thinking of seeing it again.

The River of No Returns?

Most of you will recognize that as a common nickname for Amazon, the biggest online shopping force there is, for its history of raising stock price while never paying returns (dividends) to investors.  Full disclosure: I don't own Amazon stock, but I'm a Prime subscriber, which means it seems like a good enough deal to pay for.  At least for the last couple of years.  Whether or not that continues is a subject for another day.

One reason Amazon comes to mind this weekend is because while we took a look at Elon Musk's Tesla Motors and its financial woes Friday, we also hear that Jeff Bezos is the richest man in the world, thanks to Amazon stock holdings.  Today's news is that Jeff sold $1.1 Billion worth of stock yesterday; I guess he needed some new slipcovers for the couch or something.

It might be reasonable to ask exactly what Jeff Bezos has done for the world to warrant being the richest man.  Has he invented anything, developed a new drug, a new alloy, or something that makes life better?  Has he made life better by composing new music or created a new comedy?   Well... maybe he's helped make it more convenient in an era of decreasing leisure time.

Unlike Bill Gates, who was the wealthiest man for a long time, Bezos didn't really invent anything new that I can tell.  It has probably been over 30 years since Gates ever slung code, but he did at one time.  Microsoft has arguably created wealth in the sense that it created new products from the intellects of its engineers.  Think of developing code as refining ideas akin to refining ore out of the ground into metals.   Amazon, by contrast, has made shopping more convenient in some ways, and helped define ways that online shopping works, but their main product seems to be convenience.  A few months ago, Mrs. Graybeard and I needed a covered butter dish.  After forgetting it during a Walmart run, we added a "two-fer" pair of Rubbermaid butter dishes to an Amazon order for something else, knowing that because of our Prime membership we'd have them in a few days.  Instead, a small delivery service - probably formed for such contracts - laid them on our doorstep early on Sunday morning - two days later.

As equal time might warrant, after looking critically at Elon Musk my same source, Bill Bonner's Diary took a look at "The World's Favorite Stock".  Some of what he said surprised me.

Two friends and colleagues (both former Wall Street insiders), Rob Marstrand and David Stockman, examined Amazon carefully and independently. They came to the same conclusion: The company loses money in its core retail business.

It disguises the losses with low taxes, capital leases, and accounting tricks – but the losses are real… and unavoidable.

And since that business model requires super-low prices, there is no way for the company to fatten its margins. It can’t make up on volume what it loses on each sale.

In other words, the business model is a failure.

That is no sin… and perhaps no surprise; lots of businesses never make money.

But there is something about the Amazon phenomenon that is truly remarkable – like a plant that needs no light… or a mammal that needs no air.

Amazon is one of the strangest creatures ever to lurk in the capitalist ecosystem.

The second reason Amazon comes to mind is this article that a friend sent me from CNBC: "This 28 Year-Old's Company Makes Millions Buying from Walmart and Selling on Amazon".  To be honest, the fact that it was on Amazon and not eBay was the only thing that struck me about this.  He's doing things with Amazon that I had no idea were available options for a small business.

When 28-year-old Ryan Grant was at Winona State University in Minnesota, he came up with a side hustle to make ends meet.  Twice a year, he organized textbook buyback events on campus.  He listed the books on Amazon and shipped them out to customers around the country for a profit of up to $10,000 a year.  He could use an Amazon provided app to determine what to pay for the used books and list them for sale.  All fine.  The problem was it was very labor intensive packing and shipping books around the country.  The duplex he was renting was full of books and hard to walk around in.

Enter Amazon again.  Their fulfillment services meant Grant could ship all the books in bulk using preferred UPS rates to an Amazon warehouse, where, for a fee, the online retailer handled processing and shipping out each individual order. It made his side hustle more manageable, time-wise.

After graduating, Grant started working in accounting.  He eventually became discouraged with that career field and while trying to think about a new career got the idea to renew his side hustle, only this time with a bigger focus than just textbooks.

After work and on the weekends, he scoped out the clearance aisles at Walmart, scanned a few items using Amazon's app and bought up toys, games, and home improvement items he realized he could re-sell for a profit. A receipt from his early days shows a variety of purchases, everything from vacuums to Barbies, LEGO sets to stainless steel flatware.

The article goes on to describe how he turned part time work on the side, pocketing about $1000 per month quit his accounting job in 2013 and developed an $8 million/year business.  

"I went from just me in this business doing around three-to-five thousand dollars in sales per month and now, four years later, we're a team of 11 and we're doing well over $200,000 in sales per month," Grant says. The team had to move to a warehouse that's over five times as large as their first this past July.

Since he started selling on Amazon, Grant says the business is on track to top $8 million in total sales by the end of this year. Profits are heavily reinvested back into the company, though Grant was still able to take a salary of around $150,000 when he was working for the venture full time.

(Ryan Grant - CNBC photo)

And more power to him.  I have absolutely no problem with someone buying at Walmart and selling on Amazon: willing buyers and sellers and all that.  If you shop around and buy it at what you think is the best price, why would you care if he's buying it on clearance and selling it for a profit?  It's especially ironic considering the online "e-tailer wars" between Walmart and Amazon.  It's no secret Walmart is trying to be the dominant e-tailer.  Walmart is trying to vanquish Amazon and hear the lamentations of their women. 

As I said, the only thing about this that really surprised me is that the "side hustle business" was on Amazon and not eBay.  Over the years, eBay has turned from a place where people sell their leftover Beanie Babies or Pez dispensers (how it started) to a 24/7 flea market populated by a lot of small businesses.  Sure, you can buy someone's old Tee shirts, their ham rig, guitar, bicycle or what have you, but when you search listings, you find a lot of small businesses.  I think some buyers just prefer to buy from a shop over Some Dood selling his stuff.  We have known people who hustled around town to buy things and sell them on eBay.  On the other hand, we've bought some tools and other small things from an eBay seller after comparing them to Amazon or other suppliers we know and had the item arrive here in an Amazon fulfillment box.

How do these stories tie together?  Could it be that the most important thing Amazon has done is sell its fulfillment services and their app that helps find prices to help small business people figure out a market? 

God Help Us All

In the Austrian city of Salsburg, they're putting airbags on lampposts because of people walking into them while looking with their phones.

Lampposts are being covered in airbags to stop so-called 'smartphone zombies' bumping into them as they walk around staring at their screens in an Austrian city.

Salzburg authorities say tourists are increasingly hurting themselves by not looking where they are going while checking their devices.

Locals have described mobile phone users as Smombies, the short form for a 'smartphone zombie', and civic chiefs are taking action to stop them getting injured.

They call this an educational program to get people to be more aware of the world they're in and they believe it will change behaviors.  I doubt that.  This is being run by the city Board for Traffic Safety (KFV in Austrian) so that tells me the tax payers are paying for this (you can see their logo in the bottom right of the sign on the lamppost).

Actually, the worst part of this story is that Salsburg isn't the only place.

In China, there are special sections of certain pavements that are reserved for people using telephones and walking at the same time.

In Honolulu anyone crossing the road and looking at their phone will be fined.

In the German city of Augsburg they have started putting traffic lights on the ground where they can be more easily seen by people staring at smartphones.

I don't know what to add to this. 

Is Tesla Motors Heading for Collapse?

That's the provocative idea from financial anlyst and publisher Bill Bonner in one of his daily letters this week.

The reasons are simple and financially obvious.

The company’s market cap – the value of all its outstanding shares – is at $53 billion. That’s higher than Ford’s market cap, despite Ford making profits of $4.6 billion last year and Tesla losing $67 million.

And Tesla has almost as high a market cap as GM, which had more than $9 billion in earnings last year… and which sold 10 million vehicles versus Tesla’s 76,000. ...

And the losses are getting bigger; a record $619 million in capital disappeared in the last quarter alone.

Graphically, from farther down the piece:

There is no rational reason for Tesla to have a market cap 80% of GM's when they ship 3/4 of 1% of the number of cars GM does (76,000 vs. GM's 10,000,000).  If the reason for the stock market price isn't the pure financials of the company, then it becomes the personal mystique of Elon Musk.  A Cult of Personality around the owner of the company.

Anybody remember John Delorean and his Delorean Motor Cars company?  The same sort of story 40 years ago in the 1970s.  The Delorean was sleek and futuristic with its gull-wing doors.  With a largely stainless steel body, it didn't require the painting and finish upkeep that entails.  It was the car that had to be chosen for "Doc" in the "Back to the Future" movies.

(image source)
While John Delorean might have been visionary, he never returned on investors' money. 

Poor Mr. DeLorean launched his car company in 1975. Over the next years, he took in – and mostly destroyed – approximately $100 million.

Toward the end, he was so desperate for financing that he was an easy target for the feds’ entrapment program. Claiming to be investors, FBI agents coaxed him into talking about importing $24 million worth of cocaine into the U.S. and taped the conversation.

DeLorean beat the rap, but DMC went bankrupt in 1982.

Later, he faced challenges from investors and car buyers and was driven into personal bankruptcy, too. He lost his home in 2000. Then he lost his mind… suffering strokes, which killed him in 2005.

Much like reasoning that you don't want to turn your government over to a charismatic con man, you don't want to invest in a company run by a charismatic con man.  Yeah, I know, times are different now: nobody invests for the long term on the company's actual value.  They buy stocks, let them pump up some amount, sell them to a bigger fool and move on to the next target.  By any conventional measure of stock values the entire stock market is overpriced and due for a major correction. 

Is Elon Musk that charismatic con man whom we shouldn't invest in?  I know some of you think so; you've said so here in comments to other articles.  There's something behind the market's enchantment with Tesla and it's not the detailed financials.

Conclusion to Bill Bonner:

“When will Tesla’s stock promote finally implode?” asks Kupperman.

Answering his own question: “When people realize that it’s a cash incinerating vanity project for Elon Musk, at a time when newer, better products are coming to the market. That point is coming soon. Very soon.”

Check Your Fire Extinguishers

I'm not sure everyone has heard about the massive Kidde fire extinguisher recall, but Kidde is the giant in the field and more than 40 million fire extinguishers are affected.  There are two lines of fire extinguishers affected: plastic-handled, and push button. 

The US Consumer Product Safety Commission announced the recall of more than 40 million Kidde disposable fire extinguishers Thursday, saying they may malfunction during an emergency.

The faulty extinguishers are equipped with plastic handles and push-buttons and can become clogged. Their nozzles also may detach with enough force "to pose an impact hazard," the CPSC said.

The recall covers 134 models of Kidde plastic-handle fire extinguishers manufactured between 1973 and August 15, 2017, including models that were recalled in 2009 and 2015. It also includes eight push-button models manufactured between 1995 and September 22, 2017.

The company has set up a web page with a couple of pages to help you determine if your fire extinguishers are included - Kidde labels their products for dozens of companies.  We just spent the evening inspecting the four we have in various places around the house, and all but one are affected.

Replacements can be applied for online.

If Kidde determines that you have an affected model, the company says it will send you a replacement within 10 to 15 business days. The new extinguishers contain metal parts instead of plastic.

NASA Prepares a Probe to Get Closest to the Sun Ever

I hereby promise not to make the joke that they'll fly at night.

NASA scientists and engineers at Goddard Space Flight Center are preparing a mission to observe the sun from closer than any probe ever flown.  For comparison, Mercury orbits the sun at a distance of 36 million miles.  The new probe, named after solar astronomer Eugene Parker, will navigate a complex series of orbits which all fall inside Mercury's orbit.  The final orbit will be 3.7 million miles above the "surface" of the sun, in the super heated corona. 

[NASA is]  putting the finishing touches on the Parker Solar Probe, a 9-ft., 10-in.-tall, 1,350-lb. spacecraft that will take off sometime between July 31 and Aug 19 of next year on a 6.9-year mission to explore the sun.  The probe will be sent on its way atop a second stage mounted on a Delta IV heavy Lifter. It will go into a fairly eccentric elliptical orbit around the sun (see figure below). It will orbit the sun 24 times, and on seven of them will make flybys of Venus to increase its speed and tighten its orbit. The last orbit around the sun will take only 88 days traveling at up to 450,000 mph.

That speed of 450,000 mph is the fastest any man made object has flown by a large margin - the previous record holders were NASA's Helios I and Helios II probes (1974 and 1976, respectively) at 157,000 mph (253,000 km/h).  Still, Parker's 450,000 mph is .00067 of the speed of light.  At that speed, the nearest stars are over 6400 years away.  Add in the fact that we have no known way to generate that speed without multiple gravitational slingshots.

The probe will carry instruments to study magnetic fields, plasma and other energetic particles; it will also image the solar wind, a stream of ionized gases that can blow through the solar system at more than a million mph. The probe’s three major scientific objectives are to:

• Trace the flow of energy that heats and accelerates the solar corona and solar wind.
• Determine the structure and dynamics of the plasma and magnetic fields that are the sources of the solar wind.
• Explore mechanisms that accelerate and transport energetic particles.

 

Of course, the danger here is the heat from the sun, so the probe will be positioned to always have its heat shield between the sun and the sensitive instruments. 

The primary bulwark against the heat is the Thermal Protection System, an 8-ft.-diameter, 4.5-in.-thick heat shield made of carbon composites that will protect most of the spacecraft’s components from the full brunt of the heat—up to 2,500°F. It is imperative that the probe maneuvers and changes its attitude to keep the TPS between the sun and the probe’s internal components. But the nine-minute lag between when radio messages on position and speed are sent and received at controllers on Earth—and another nine minutes for the adjustments to be radioed back—meant that engineers had to make the Parker as autonomous as possible and able to maneuver on its own to keep the TP correctly positioned. This makes the probe one of the most autonomous spacecraft ever built by NASA.

The 4.5-inch thick carbon composite heat shield isn't enough.  The reality of powering the spacecraft means that it has to deploy solar panels, photovoltaics, to convert the intense sunlight into electrical power.  NASA learned during the Mercury Messenger program how to manage the heat that ultraviolet radiation in sunlight causes in photovoltaics.  The heat eventually degrades the solar cells to unusable output levels.  The Parke probe's solar cells will be mounted to a metallic channel that will have cooling water pumped through it, to reduce the temperature of the cells. 

The probe will also use its autonomous capabilities to keep the adjustable solar arrays or wings as shielded as possible, but still exposed enough to generate power when needed. This is critical: NASA estimates that at some times during the probe’s mission, a change of only one degree in the solar arrays’ wing angles would call for a 35% increase in the liquid cooling subsystem’s output.

I find it cool that plain old deionized water is being used on a mission to the sun to keep the solar panels below a temperature of  320F. 

The mission has a web page with more interesting background, as does Machine Design. 

Odds and Ends on the Night of a Sudden Jihadi Attack

New York City this time, on a bike path in the yuppie heart of the city.  No ARs, no bump stocks, no guns at all - just enough BB guns to ensure "suicide by cop" and go collect his 72 virgins.  Except this is NYPD we're talking about here, and we're lucky they gut shot him and didn't just kill nine other people on the bike path. 

H/T to The Abode of McThag for the "why didn't I think of this" post of the day:

If only it were mandatory to register any vehicle which will be used on a public roadway.

If only it were mandatory to obtain a license to operate such a vehicle before driving it on a public roadway.

Probably keep them from being used for criminal activity.

That's it!  Mandatory registration of all pickup trucks, so that they're not allowed on the roads without registration.  We'll make them carry a state-issued, metal plate to prove they're registered!  Mandatory licensing and training of anyone who would own, or rent a pickup truck.  We'll make the drivers pass a state-given test and make them carry it as photo ID to ensure they're licensed to use that truck. 

In other words, all of the gun control arguments in two sentences.  If he had put a brick on the accelerator to speed his rental truck we'd have the bump stock argument, too. 

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Blog administrivia.  I made some unannounced changes a few days ago and have been in a slightly different direction for the last couple of weeks.  First, I added a note about comments, hoping people would see this:

Comments are always welcome, with the same provisos as everyone: keep it civil, and no spam. All comments to posts over 14 days are moderated, but only spam is deleted on sight.

Everyone handles comments differently.  Some of us reply to each and every comment and strive for conversation; others (and I'm one) tend to not answer unless it's a specific question or seems to be directed at me.  I'm not likely to answer things that seem to be for everyone.  I'll be the first to admit that's not like a law of physics that can't be violated.  Sometimes it can be hard to tell.

That said, comments are always welcome, contrasting opinions are always fine, and the only comments I ever delete are those that are obvious SPAM.   I'm talking to you, "Packers and Movers of Bangalore"!

The other change is in the blog description, which I bet nobody reads. I changed it back closer to what it used to read.

The focus of this blog is on doing things, from radio to home machine shops and making all kinds of things, along with comments from a retired radio engineer running from tech or science news to economics; from firearms to the world at large.

I intend to do more of the "how to" and "what is" (i.e., explanatory) kind of posts.  These take a bit more research and time, but are more helpful to people than the typical "X happened in politics today".  Not to mention more interesting.  This will include more posts like the one on Voyager, looked at the from radio designer's link budget view.  I will also keep posting news that I find cool or interesting from either the engineering trade magazines or the big shows.  And, of course, I intend to be more than just a gun-friendly blog, and anything interesting or new to me from the shooting world will be posted, too. 

That said, Blogger says that around 1500 unique visits happen per day, and I have to assume readers are coming by for something.  If there are things you'd like to see addressed, drop me an email - the address is in the right bar under "Contact Me": SiGraybeard at gmail dot com . 

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That said, let me give a peek into my next little shop project.  They're called soft jaws for the lathe. The hexagonal pieces in this view from that website.

What are soft jaws?  The jaws on the lathe chucks and machinist's vises are hardened steel that can and will mar the metal you're working on.  You end up having to machine away the damage from machining the part.  These soft jaws will be made from a bar of aluminum hex stock, which won't mar steel as badly as steel jaws can.  When I built my little steam motor the other day, the two shafts were held in the lathe jaws for threading, and the shaft of the one that was critical, the 1/4" diameter main shaft, was boogered up by the lathe. Nasty marks that I had to file down, which made the fit even worse.  Soft jaws should prevent that.

It falls into the category of an old story I read when I was first getting into machining:

Watcha makin?
Tools.
What for?
To fix my other tools.
Why?
So I can make more tools.

Tools for making tools for making tools.  Sometimes.

Largely Wasted Day

Today was largely spent on hold on the phone with our bank, which is actually a local credit union.  We switched over to them a couple of years ago from Wells Fargo.  I know it was between different Wells scandals, but I'd have to try to remember which scandals they were.  The credit union has been excellent: they offer all the services we want, they've been very easy to work with, and they've paid us higher dividends than we earned at the big bank, by large margins.  In every instance, they've been equal to or better than Wells Fargo. 

This past weekend, they unveiled a new "digital banking system".  It's probably best described by just calling it inept.  I actually thought the web site had been hacked by Nigerian scammers, some ransomware pigs from Eastern Europe, or some group that was just as adept at fraud.  The CU never posted any big alerts on their website saying "Big Change Coming This Weekend!  Learn About It Here!".  They never sent emails.  They never communicated anything.  Mrs. Graybeard goes to check something Friday night and the previous system of logging in, which involved echoing back answers to one of a handful of preset questions, is gone.  In its place a simple User Name and Password.  And it only allowed two tries before locking us out for the weekend. 

We called in to get the password reset at about 9:30.  We were caller 89.  The call wasn't completed until close to 11:30.  That's when we found out that we needed a special identifier for each computer that would log onto the system, which might have been what the system was waiting for Saturday.  When I logged on a bit later, I found that a scheduled payment had been lost when the change was made, and wasn't paid when it should have been last Friday.  Back to the phone for another couple of hours to track that down. 

There are more aspects that wasted time - it really was total fustercluck.  I've never seen a digital changeover this clucked up. 

On the other hand, the day was gorgeous and it was nice to wander outside a few times.  I rolled out the cold smoker and smoked a couple of pounds of cheese (cheddar and pepper jack), then switched to hot smoking and smoked 5/4 of a chicken (a tray of chicken quarters).  Fall has finally arrived here in the Silicon Swamp.  Thursday morning it was 53, Friday about the same, Saturday was rainy, and it cooled off again yesterday.  It was 47 this morning and about the same is forecast for tomorrow, before warming for few days and settling into a string of more or less 70 low and 80 high for the next week.

Finally, I just have to repost this picture, even though it's completely unrelated to anything in this post. 

Did you know if you put a marshmallow Easter bunny into a bell jar and subject it to higher pressure, it turns into Kim Jung Un? 

As Daylight Saving Time Ends, Some Plan an Exit Strategy

Next week is the weekend we all "fall back" and go back to standard time.  As DST ends, though, some New England states are looking for a way to eliminate DST and stay on one time zone all year long, according to a story at The Weather Channel.

• As Daylight Saving Time's annual end approaches, some New England leaders are discussing a plan to eliminate it.
• Their plan would move three states – Maine, New Hampshire and Massachusetts – one hour ahead, to the Atlantic Time Zone.
• Supporters say it could help the states that adopt the change, while detractors say it would do the opposite.

Frankly we hear this sort of thing every year at the start and end of DST, so I don't give it much chance of happening, but I've never heard of the approach of going one time zone forward.  That's equivalent to staying on DST all year long from the standpoint of being in the Eastern time zone.  They'd "spring forward" once and stay there forever  TWC links to an article on Quartz and I'm going to bounce back and forth between them. 

There are well-documented costs of changing clocks each year, including car accidents and heightened stress. Not every country, or even state, observes twice-yearly time changes, and those that do, change clocks on different days. It creates a semi-annual state of chaos.
...
Written by public health advocate Tom Emswiler, he argued that the 99-year-old tradition should go by the wayside, at least in New England, because sunsets at 4:15 p.m. aren't just inconvenient – they're negatively affecting business. For one, Daylight Saving Time is a farming-driven idea, and with so few farms in New England, there isn't much need for the time change. Secondly, Emswiler said the early sunsets might drive college students elsewhere to areas where it's not dark by 4:15 p.m. in the dead of winter.

I've also seen articles written by farmers who hate DST as much as anyone and say they have no particular use for it either so don't blame it on them.  In fact, the idea that it was for the farmers is just part of the mythology behind DST, at least according to Popular Science Editor Rachel Feltman, writing in the Washington Post on "5 Myths About Daylight Saving Time".

In fact, the inverse is true. “The farmers were the reason we never had a peacetime daylight saving time until 1966,” Downing told National Geographic. “They had a powerful lobby and were against it vociferously.” The lost hour of morning light meant they had to rush to get their crops to market. Dairy farmers were particularly flummoxed: Cows adjust to schedule shifts rather poorly, apparently.

It's unavoidable that we'll face longer days in the summer and shorter in the winter.  That change in sunlight hours is part of the change of seasons  caused by the 23.5 degree inclination of Earth's orbit.  I'd guess that most of us have traveled enough to notice that day and night length vary with latitude at any time of year, and it gets more extreme the farther toward the poles you go.  Here in the southernmost reaches of the US, (I'm not in the tropics - none of Florida is) we have less variation.  On the summer solstice, our day is just short of 14 hours long - 13:55:30.  On the winter solstice it's 3 hours 34 minutes shorter, 10:21:43. (source)  In Minneapolis, MN, the longest day lengthens to 15:36:48 - just over two hours longer, and the shortest day shortens down to 8:46:12, virtually seven hours shorter than their longest day.  Nothing can be done about that.  All DST does is change what we call those hours.

(Day length vs. Latitude for the year.  Source)

 

I Have a New Goal in Life

From Common Sense Evaluation:

A site that's hard to categorize, but more than occasionally funny.

Meet Mr. Green

Mr. Green is the name we've given to a new resident of the back porch. 

For all I know, this is Mrs. Green; they don't exactly have ways of conveying that information, so I'll use the sexist stereotype and use the masculine name.  Yeah, I know:  I'm a hater.  Further, we know there is a Mrs. Green.  We've seen them engaged in martial behaviors, if you get my drift.  I saw her hounding him to take out the garbage and throw out those tiny beer cans.

We first saw him back before Irma, and we encountered him several times while putting up and taking down shutters. 

Why do I care?  When I grew up in Miami, green lizards like this were everywhere, and we called them chameleons.  I don't know if Mr. Green can change colors, but there doesn't appear to be any effort on his part to change color to match his home, a fossil clam geode from Ft. Drum, Florida (one of a small handful of places where collectible minerals can be found in Florida).  The chameleons I grew up around would get kind of reddish, brown, or bright green.  I remember seeing one jump onto a plaid chaise lounge chair by the swimming pool where I had a summer job, and watching the poor lizard get confused trying to change colors to match the plaid.  I think he died of a hernia.

No, I made that up.  The little green lizards disappeared when invasive Cuban Brown Anole (pronounced "a-no-lee") lizards spread into more ecosystems.  By the 1990s, the Brown Anoles were the most common vertebrate in Florida.  Until we spotted him in the yard, I hadn't seen a little green lizard like Mr. Green here in long time; probably since the 1970s.  What kind of lizard is it really?  I don't know.  I think he's a Green or Carolina Anole, but the pictures vary and I don't know what key identifying characteristics to look for.  As long as he eats bugs, he's welcome. 

There's a Fine Line Between Hobby and Obsession

and Jack Bally crossed that line about 10 years ago.


Back in January of 1999, Jack Bally was having a few beers with friends and thinking of his next project.  Presumably it was because alcohol was involved that Jack decided to get a set of scaled plans for a B17 bomber from the RC hobby world and make it a plane that a human pilot would fly.  Jack bought a set of 1:9 scale plans and scaled them up to 1:3.  This video was made in 2016, and at one point in the video, Jack said he had been working on it 17 1/2 years.

SPECIFICATIONS

Wing Span: 34 ft. 7 in.

Length: 25 ft.

Tail Height: 6 ft. 10 in.

Power Plant: 240hp

Fuel Capacity: 42 gal.

Empty Weight: 1800 lbs. (Est.)

Cruising Speed: 110 kts. (Est.)

Crew: 1

Number Built: 1

It was reported by the Experimental Aircraft Association that Jack's plane had its first flight on November 14, 2016, taking a short hop from his own small field to a local airport for more testing.  It was just three months after the previous video was shot.

I thought Pierre Scerri's model Ferrari 312 PB was the most amazing model I've ever seen.  I need to broaden my category of "most amazing model I've ever seen". 

A Shot Back at Google/YouTube Censorship

By now, everyone has heard horror stories about YouTube refusing to allow some small gun channels, like The Firearms Blog, and Royal Nonesuch to monetize their channels with ads.  I hate ads as much as the next guy, but I understand that for someone with legitimate costs for putting content on YouTube ads may be the only way they can make up some of those costs.  My YouTube channel has been unaffected, as far as I know, but I don't make any attempt to monetize it and it's essentially an extension of this blog.  Aside from a short video of cutting out the fire control pocket on an 80% AR lower, there's no gun content and no political content, so perhaps I'm under their radar.

It's worse than just shutting down small gun video guys; they're also censoring or even refusing to run videos from people with conservative viewpoints, or restricting them to their equivalent of XX rated.  Bill Whittle's channel has posted about this, as have comedian Steven Crowder and others.

The latest to suffer being shoved aside by YouTube is Dennis Prager, whose Prager University produces short, high content videos with a strong moral and conservative viewpoint - what everyone over the age of 40 grew up hearing as "common sense".  Unlike everyone else, Prager apparently has the resources to sue YouTube and Google for discrimination. On his own website, Prager lists a very short explanation:

Little David, PragerU, is taking on the mighty Goliath, Google/YouTube. It’s a free speech issue. Google is restricting over 30 PragerU’s videos for being violent, pornographic and unsuitable for children — no kidding. This is nonsense, of course, the real reason PragerU’s videos are restricted is ideological.

He then links to a longer explanation on Fox Business.

A lawsuit filed Monday evening in federal court in San Francisco says YouTube's more than 30 million visitors a day make the site so elemental to free speech in the digital age that it should be treated as a public forum. The suit argues the site must use the "laws governing free speech, " not its own discretion, to make decisions about what to censor. 
...
Since last year, more than three dozen PragerU videos -- on subjects including the Korean War and Israel and Palestine -- have been restricted by YouTube. As a result, those who use YouTube in "restricted mode," including students at some universities and children whose parents have put parental control filters in place, are prevented from seeing the videos; all potential ad revenue from the videos is also cut off.

I can't say that I've watched all of PragerU's videos, or even most of them, but calling them violent, pornographic or unsuitable for children doesn't sound like anything I've seen.  PragerU videos may touch on non-PC subjects, like why murder is wrong, or question that some cultures may actually be better than others, but being politically incorrect is not pornographic, nor violent, and may - horror of horrors! - lead children to think.

YouTube, like all online and broadcast media, has been hammered by well-orchestrated campaigns by groups like Media Matters, a far left organization that was founded to destroy Fox News and destroy any media voices they disagree with.  That's not me saying it, that's Fox News' liberal analyst Juan Williams.  And, yes, Media Matters is another one of George Soros' trained monkeys.  They apparently ran the campaign to get Bill O'Reilly kicked off the air, one of their biggest victories. 

One of Media Matters favorite tactics is to threaten companies with boycotts if they advertise with one of those voices they don't like.  If they convince YouTube not to allow those "icky gun videos", they're going to hurt TFB or Demolition Ranch, but Springfield Armory or Savage or any of  the other gun makers are going to still be there.  Their YouTube channels are part of their advertising budget.  They're monetizing YouTube, not the other way around.

Organizations like Media Matters and the rest of Soros' harem have focused world governments on the internet and turned the issue of censorship into government regulation issues - which is just what a globalist like Soros wants.  As Juan Willams says, "There are many words one could use to describe Media Matters but there is one thing they are not: liberal", and he's absolutely right.  They're tyrannical, One World Government types who want power over everyone.  Dictators don't care about your free speech, only their own.

Sharyl Attkisson wrote a very interesting sounding book about Media Matters (among others) and their tactics called, "The Smear", subtitled, "How Shady Political Operatives and Fake News Control What You See, What You Think, and How You Vote".  She's a victim of The Smear herself, and it's an interesting interview to hear her talk with Glenn Beck - how Media Matters got him off Fox is part of her book. 

Like it or not, this has turned into an argument over YouTube as a public utility, which invites the heavy hand of government and that almost never ends well.

The swarm of companies that all emerged from or were absorbed into Google - YouTube was one of the first, IIRC.  Now they're collectively called Alphabet.