Tips, Tricks, and Musings from GoldSpire Design LLC

Author: goldspireblog

Upsetting the Apple Cart

You would have to be living under a rock to not notice the sweeping changes that are taking place in the American economy.  From my viewpoint in the tech sector, this transformation began just over two decades ago, and has been picking up speed over the last ten years or so.  Technological advances, combined with social forces, are interacting in an exceedingly complex manner, turning the very nature of “work” and the process by which economic value is created, on its head.  We are witnessing a transformation of the economy even greater than that of the Industrial Revolution of the 19th century, and while we collectively debate the pros and cons of the changes that we see taking place, the disruption of the economic status quo currently underway will not be fully understood for at least another generation.  Historical clarity is not unlike a rear-view mirror – it only becomes possible to understand what happened in retrospect, when the entire “big picture” is visible.  When we are in the midst of any kind of tempest, it is generally impossible to see the overall picture since we are focusing on the small details that are in front of our faces.

The technological miracle that is the Internet has transformed our lives in ways far too numerous to count, but at its most fundamental level the Internet has created an environment where wideband communication between any two points on the earth is essentially instantaneous and is accomplished at practically zero cost.  This reality makes it possible for individuals in many “information-based” industries to “work from anywhere” instead of being attached to a specific location where the technological and social infrastructure necessary for their job exists.  We have all read about the rise of the “Digital Nomad”, that lucky individual who develops Java code while sitting at an outside café in Phuket, Thailand, and is planning to drift across Asia and Europe over the next year while they complete the ten projects that they have queued up in their email Inbox.  We have also read about many not-so-lucky individuals who are out of work because their jobs have been moved to some other part of the world, where individuals can easily be found to perform the same work at a fraction of the cost.  I’m sure many of you reading this article right now know someone who has been made redundant through the process of “job off-shoring.”

Coincident with the ground-shaking changes brought upon us by the reality of the Internet (and in many cases fueled by it) is the belief that life should be devoid of any risk.  This is especially true in American society, where many people believe that protection from even the slightest form of injury, whether physical, financial, or social, is somehow a “right” that must be protected.  In the event that something bad does indeed happen, there is an immediate search to find a responsible party that can be blamed and forced to provide compensation.  A close corollary to this is the belief that, as individuals, we should be free of having to make sacrifices (lifestyle, financial, or other) in our lifestyle choices, i.e., lifestyle choices come with no additional responsibilities.

What does a collective belief in “risk-free existence” have to do with the American economy?  Consider the effects of the following:

  1. Multiple opinion polls indicate that more than half of all Americans believe that health care is a fundamental right
  2. A substantial number of Americans believe that both men and women are entitled to paid leave to care for a newborn baby
  3. The expectation that all individuals possess the right to be protected from anything that might possibly be construed as “offensive” or “unpleasant”, without having to take into consideration the rights of others (this can be thought of as a symptom of the breakdown of what the Greek philosopher Aristotle called the “civil society”)
  4. The rejection of belief in a set of absolute moral standards for behavior and interaction between individuals. Without a common agreement of what is considered to be “moral”, interactions between individuals are governed largely by a legal framework, which by its very definition is adversarial in nature

I could continue with other examples, but for now that would take me too far afield from the topic at hand, which is the upheaval we are seeing in the economy of the United States and the rest of the world.  The four items that I have listed above are all illustrations of the erosion of personal responsibility that is now taking place in American society.  Using both the political process and the legal system as tools, many different groups of individuals have been successful at enacting laws that incrementally take away the burden of personal responsibility and place that responsibility on other individuals or groups.  Caught in the crossfire of this legislative and judicial mayhem is “Corporate America”, frequently viewed by both politicians and the public as bottomless pits of money that are expected to shoulder all the responsibilities of the individuals that they employ.  With an ever-increasing burden of rules that dictate to employers how they must interact with their workers, the employer-employee relationship has become so complex that an entire new industry (commonly known as Human Resources) has developed in order to manage it.

Many of you are likely thinking, “Wait a minute — Human Resources departments have been around for decades… they are the folks that manage the recruiting process.”  That is true, however recruitment is no longer the primary focus for HR departments, and hasn’t been the primary focus for well over a decade.  The primary focus of HR departments nowadays is managing the boatload of regulations that govern the relationship between employer and employee, the main goal being protection of the organization from actions the employee may take against them.  Rather than being viewed as assets to a company, employees are increasingly being viewed as potential liabilities that increase the company’s operating costs in ways that are often unpredictable.  The end result of this process is quite predictable, and it is easy to see everywhere in the economy:

  1. Employers intentionally understaff departments (this is euphemistically called “running lean”), and oftentimes are less likely to replace workers that leave the company
  2. Employers increasingly rely on outside contractors to provide them with a labor force. This allows the employer to avoid taking on the financial and legal liability associated with an employer-employee relationship.

It is the second item in the above list that I wish to focus on in the discussion that follows, and while it is likely applicable to many different industries, I want to state at the outset that I am writing from my own perspective as an engineer working in the electronic technology sector.

Like it or not, the tendency of companies to utilize outside contract engineering for product development is on the rise, and will likely continue into the foreseeable future.  In effect, many companies are doing the equivalent of “voting with their feet” as a reaction to the ever-increasing encroachment of government regulation into their operations.  Rather than knuckling under to government mandates regarding employees, companies are simply opting to “not play the game” – if a company has no employees, it cannot be held liable for the actions of an employee, nor does it need to incur all of the additional costs mandated by the government.  Perhaps the finest example of this is the recent “Fight for Fifteen” movement – a group of activists lobbying state and local governments to pass laws increasing the minimum wage to $15 per hour.  The success of this particular lobby has been mixed, however in places around the country where they have been successful, the long-term result has been entirely predictable:

  1. Reduction in the number of working hours per each employee
  2. Closing entire businesses and moving them to other jurisdictions without minimum wage laws
  3. Adopting automation in a business where it did not previously exist

The last item above is a boon for tech workers like myself – bring on the robots!

In whatever form job outsourcing takes in the tech sector, its increasing presence in the American economy means that, as engineers, we need to take responsibility for our own careers, and look at ourselves as our own enterprise.  This reality is a double-edged sword – while the thought of working independently and being the champion of your own destiny can be exciting, it requires a level of resourcefulness and motivation that is substantially higher than what is required of most individuals who have a traditional employer-employee relationship with a company.  Rather than having an employer provide them with a steady stream of work that produces economic value, it becomes the responsibility of the individual to seek out and secure work on their own.  This is an inherently difficult task, as it requires skills in marketing, business development, sales, project management, finance, and probably a few other skills that escape me at the moment.  This preliminary list is enough to use as a starting point – engineers and other tech workers are generally terrible at most of the skills that I have listed, and even if some tech workers understand the intricacies of business development and finance, it is likely that they don’t really enjoy doing those things.

The requirement that a tech worker (or anyone else) become their own enterprise when they work as a contractor exposes a critical, but often overlooked role that companies play in the economy as a whole.  Companies, through their very existence, act as a “force multiplier” in the economy, by concentrating labor and expertise in one place in order to create economic value that is greater than the sum of the individual contributions made by the workers.  A simple example – 1000 engineers working in their individual garages cannot design and build a Boeing 787 Dreamliner, but 1000 engineers working together in a factory certainly can!  What is equally important to observe is that a significant component of the value that is created through collaborative effort is the institutional knowledge and expertise that is contained in the minds of the individual employees.  So long as a company maintains a body of employees that are committed to their work (and to the company that employs them), it retains the expertise that enables the company to compete, and hopefully excel in the marketplace.  The employee benefits from this relationship as well, primarily in the form of a steady and regular income.  It is not just the effort of the individual employee that creates the value that results in their income – it is closely tied to the force multiplication effect that the company provides by concentrating expertise in one place.

Perhaps in this day and age the previous paragraph could be considered heresy – after all, the only responsibility a company has is to its shareholders, right?

This article is not meant to be a political position paper for GoldSpire Design, but is meant to provoke thought among all of my readers.  I began this article by discussing the Internet and how it is fueling a transformation in the world economy that is nothing less than apocalyptic, but in a way that is perhaps more equitable than the Industrial Revolution.  The Internet gives everyone equal access to the economy and the marketplace of ideas, serendipitously at the same instant that many tech workers will need to become their own independent profit centers.  Freedom is a wonderful thing, but one needs to keep in mind that it is also unsympathetic.

The intent of this article is to be an introduction to a larger discussion that embraces the following questions:

  1. In a world of individual consultants, how do each of us seek out and secure economically valuable work?
  2. What effect will the large-scale outsourcing of tech sector expertise have on individual companies, as well as the economy as a whole?
  3. What new types of business models and business relationships will need to be developed among individual consultants to create a “force multiplier” effect?
  4. Is it possible for tech workers who are transitioning from the traditional role of an employee to independent consultant to retain their standard of living, given the absence of the “force multiplier” effect of being associated with a company?

Over the next several installments, I will discuss some of my thoughts in these areas at greater length.  In the meantime, I encourage all my readers to give me your thoughts, ideas, and opinions regarding these very important issues.  That these issues are important is confirmed by many discussions I’ve had with my colleagues over a long period of time.  We are all thinking the same thing, so I’m sure many of my readers out there are thinking about them as well.

 

 

Its Easy to Build One Unit of Anything

Several weeks ago I was reading an article about Microchip Technology Inc. and a history of their growth and success in the embedded microcontroller market.  It was an interesting read for several reasons — first, because I’ve been using Microchip PIC devices in my work since the mid 1990s;  second,  their success in the market given the increasing diversity of their product line over the years is truly impressive, and lastly because I really enjoy designing with their devices — they are inexpensive, and the development tools are very easy to use and are well-documented.  At the bottom of the article in the comments section, someone posted a comment which went something like this:

Its so sad that people are still designing with PICs — we’ve got Raspberry Pi now!

Sigh.  Ten years ago my first reaction to a comment like this would be to fire up the pilot light on my cyber flamethrower and push the throttle to the “full open” position, however with age comes tolerance and understanding, so I decided to provide the well-intentioned, but woefully ignorant poster with a bit of constructive criticism.  I replied with:

Nobody is going to build one million pieces of ANYTHING with a Raspberry Pi…..

I have no axe to grind with Raspberry Pi — they are a very interesting set of products that have a tremendous following among techies, hobbyists, students, and others.  However, the implication that the mere existence of the Raspberry Pi should have Microchip Technology preparing their Chapter 11 filing brings to light two fundamental and deep misunderstandings about product development specifically, and more generally, the technology market.

The Raspberry Pi Foundation has tapped into a very interesting market — they have essentially taken the concept of a single board computer (which is nothing new, as SBCs have been around for two decades) and made it “cool”.  They deserve to be complemented for this, as they have brought an extremely versatile product to the masses at a very low price.  These tools make it extremely easy to build very sophisticated systems relatively quickly by individuals that possess a minimum of electrical engineering design talent.  A cursory web search for interesting Raspberry Pi projects brings up all sorts of things that are incredibly nifty — one individual actually launches Raspberry Pi’s into the upper atmosphere using balloons, and takes photos from the edge of space!  There is no question that the Raspberry Pi has revolutionized the junior high and senior high school science fair project offerings for many years to come — I wish I had access to one of these gizmos when I was in junior high school, as I could have used it to control the spacing between the electrodes of my carbon arc lamp (I won a blue ribbon in the school science fair for that project).

But, as the title of this blog entry states — it is easy to build one unit of anything, and “A prototype does not a product make.”  The Raspberry Pi would be an excellent low-cost platform to use for the development of a product proof-of-concept for a device which needed all of the functionality offered by a high-end ARM processor.  It would make no sense at all to actually develop a standalone product and stuff a Raspberry Pi inside the plastic — the cost associated with all the bells and whistles on the PCB would destroy the economic feasibility of the product.  That’s where the commenter’s train of thought went off the rails — having a really nifty computational platform that fits in the palm of your hand and contains more computing power than the command module on Apollo 11 does not necessarily make it applicable to be used in a product.  So much of what we do as product development engineers has nothing to do with hardware or firmware — the most important part of our job is to provide the simplest and most economical solution to the design problems that we are given to solve.  This requires us to survey the myriad of computational platform solutions available to us, and balance these against the multidimensional labyrinth of functionality, cost and price (the two are not the same!), manufacturability, development cost, testability, field support, scalability, etc.  It is in these aspects of the design process where the magic really lies — making complexity seem very simple, while eliminating as much superfluous “fluff” as possible.

The commenter also made me think about the current state of the technology market and how easy it is to lose sight of the entire forest because you are fixating on one particular tree.   While pretty much everyone around us walks around with a mobile device in their pocket, has at least one video game console at home, and goes about their errands while wearing a fitness tracker, the reality is that these systems and devices constitute only a small fraction of the entire embedded system market.  Much like an iceberg, the entirety of the embedded systems market is mostly invisible — comprised of billions (and I do mean BILLIONS) of very simple, very tiny bits of hardware and firmware that crank away constantly in devices all around us.  You’ve certainly got quite a few of these around you right now — the oven in your kitchen, your dishwasher, coffee maker, refrigerator, washing machine, thermostat, water heater, irrigation system, garage door opener — I could keep going, but you get the picture.  If you look a bit further afield there are even more — take a walk around your office, or the production floor of any factory, and you’ll find hundreds of places where some humble 4-bit or 8-bit microcontroller is whirring away silently, keeping its own little corner of the universe running smoothly.  You won’t find any Raspberry Pi’s here, but I’ll bet you dollars-to-doughnuts that you’ll find more than a few Microchip PIC processors.

It was about five years ago that Jack Malone*, my local Microchip Technology sales representative, told me that Microchip was shipping over one million of their low-end PIC16 microcontrollers each day.  You heard that right —- over one million microcontrollers each day.  Obviously, all that silicon is going somewhere — it is destined for that part of the embedded systems world that is “below the waterline”.

I don’t think Microchip has too much to worry about — their market space is alive and well.

Enjoy!

 

David

 

*For those of you in Southern California who knew Jack, he needs no further explanation.  He was a great guy who would go to the ends of the earth to help a customer in need.  In addition, he was a long-time veteran of Microchip who believed in his company’s products.  His passing several years ago was a sad day for many of us in the San Diego engineering community.

Dealing with resistor tolerance and temperature coefficient together — they both matter when choosing a resistor

There are so many complex issues in electronics design, but no one ever gives the lowly resistor very much thought.  In the overwhelming majority of cases, one simply chooses a resistor with little regard to anything more than its nominal value — and in most cases this technique works just fine.  The problem isn’t so simple when an accurately-known or tightly-controlled resistance value is required — these cases often pop up when picking a resistor used for current sensing applications, configuring an op-amp for a precise voltage gain, or temperature sensing.  Careful thought is required here, since variations in the value of the resistance that occur because of unit-to-unit variation as well as changes in the resistance with temperature will degrade the accuracy of the overall measurement being taken.  Very often, a shotgun approach is taken to this problem — just find the tightest tolerance component you can and use that!  No problem with that — until you look at the price of that 0.1% tolerance resistor in the Digikey catalogue.  If the price doesn’t get you, the variation in resistance with temperature probably will — a 10k resistor with a tolerance of 0.1% will maintain that tolerance in December just as easily as it will in August, however in both of those cases it is unlikely that it will be a 10k resistor.

The best way to go from the standpoint of good design practice as well as cost, it makes no sense to use a resistor that is any better than what is needed to get the job done.  With this in mind, I offer a simple view into how resistor tolerance and temperature coefficient are related and how they jointly determine whether or not a particular resistor is adequate for a specific application.  Take a look at the graph below:

tempco and tolerance analysis

The graph is a plot of resistance over temperature.  For this specific design, we require a resistor that has some “ideal” value at some “nominal” temperature.  While most resistor manufacturers specify their components at 25 degrees C, it is not necessary to assume that specific temperature in this case, as our discussion is completely general.  Our resistor has some component tolerance associated with it — this is shown in the graph as the narrow band around the ideal value with upper and lower values of Rtol+ and Rtol-.  For any resistor that we pull out of the box and measure its resistance assuming we do so when it is sitting at its “nominal” temperature, we will measure a resistance somewhere inside the tolerance band.  The wider band of resistance designated by Rmax and Rmin designate the largest and smallest values of resistance that are acceptable for the design.  If we ignore any temperature effects, we easily see from the graph that as long as we choose a resistor that has a tolerance tighter than the acceptable range of resistances required by the design, the resistor will be adequate to meet the design requirements.

Bringing temperature variations into the picture makes the component selection process more interesting.  The sloped lines on the graph depict the characteristics of a resistor with a negative temperature coefficient, or “tempco” — as temperature increases, the resistance decreases.  Resistors can also have positive temperature coefficients — but in our analysis here it does not matter which sign the tempco is, as the results that we will present are completely general.  For simplicity, we will only deal with the magnitudes of the temperature coefficients in order to avoid having to carry around a bunch of negative signs.  The three sloped lines correspond to resistance over temperature for resistors that are at the positive and negative limits of the tolerance band.   Notice that the temperature variation of resistance places a limit on the range of temperatures over which this particular resistor will satisfy the design requirements.  For resistors with a negative tempco,  the minimum operating temperature is defined by the upper tolerance limit while the maximum operating temperature is defined by the lower tolerance limit (for positive tempco, the roles that the tolerance plays is reversed).

The graph shows two equations for the slope of the lines (the slope is equal to the tempco expressed in ohms/C), corresponding to the slopes above and below the nominal operating temperature.  If the nominal operating temperature is chosen to lie at the center of the overall operational temperature range, these two slopes will be equal to each other, but in general the operational temperature range need not be symmetric — in which case the slopes will be different (so as not to confuse anyone — the slopes that I am describing here are “defined” as forming the operational temperature range about some arbitrarily defined nominal temperature.  The actual tempco of a resistor does not have a discontinuity at the nominal temperature).

There are two ways to approach the problem that now faces us:

  1. For a given operating temperature range and resistor tolerance, what is the maximum permissible tempco of the resistor?
  2. For a given operating temperature range and resistor tempco, what is the maximum permissible resistor tolerance?

The first approach is the easier of the two, because the answer is given simply by the expression for the slopes.  The tempco of the resistor must have a magnitude that is no greater than the smaller of the two slopes given in the graphs:

tempco and tolerance analysis2

The second approach requires a bit of algebra to get the expressions for tolerance.  Recalling that the upper and lower resistance tolerance limits are expressible in terms of a tolerance in the following way:

tempco and tolerance analysis2

Manipulating the slope equations and using the two expressions above gives us the upper and lower tolerance values:

tempco and tolerance analysis2

The maximum permissible tolerance is the smaller of the two values in the above pair of equations.

Using the results given here, it is possible to pick a resistor that will satisfy both tolerance and tempco requirements over any desirable temperature operating range.  Looking at the graph, it is easy to see that tolerance and tempco interact in an expected manner —- the tighter the resistor tolerance, the larger the maximum permissible tempco for a given overall operating range.  Likewise, larger tolerance resistors require smaller tempco to satisfy the design requirements over the temperature range.

As a final note, resistor manufacturers generally specify the tempco of their devices in units of parts-per-million (ppm) per degree C.  In order to convert a tempco expressed in these units to units of ohms/C, use the following expression:

tempco and tolerance analysis2

I hope you will find this design note useful.  Feedback is always appreciated!

 

David

Welcome to DesignGold!

Thank you for stopping by to take a look at what is going on here at GoldSpire Design!  This blog is dedicated to all things associated with electronics, electrical engineering, and product development.  I’ll be posting things that everyone will hopefully find educational, thought provoking, entertaining, and useful to you in your business or product development efforts.  If any of my readers have any ideas for new and interesting topics to discuss, please bring them up so we can all brainstorm about them.

Thanks again for coming, and hope to talk to you soon!

David

 

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