Author: Chris Gammell

Chris Gammell is an engineer who talks more than most other engineers. He also writes, makes videos and a couple podcasts. While analog electronics happen to be his primary interests, he also dablles in FPGAs and system level design.

Categories
Analog Electronics Renewable Energy

What the heck is a Smart Grid? (Part 1)

First off, a smart grid does not yet exist. It’s not exactly dumb, but it’s unwieldy and needs some help getting itself under control.

So let’s think of the electricity grid as an elephant.

It’s big, it’s powerful and it takes a ton of work to get it moving in one direction or another. It’s also really expensive to get it from one place to another. If you want to move an elephant over a distance of hundreds of miles, it’s going to want some peanuts, after all.

A Smart Grid in this analogy is the trainer that controls the elephant.  The consumer is a person off in the distance, holding a peanut. And elephants love peanuts, so they will naturally go where they are. The trainer might be able to guide the elephant towards the people willing to pay the most peanuts. The trainer might also be able to tell the consumer to save their peanuts because getting the elephant at certain times of days will be expensive. And for the health of the elephant, he can say “enough is enough” and start to scale back how many peanuts the elephant is really allowed to eat that day. In the end though, the trainer is only guiding the elephant. The things that truly are controlling the elephant are how much energy he has and how many peanuts people are willing to offer him.

So how does an elephant relate back to the actual power grid? Well, think of a typical coal power plant. The coal is used to heat water, the water turns to steam, the steam turns a turbine and then the water is cooled and recycled to be used for another cycle. The AC power is distributed to transformers that step up the voltage of the signal to thousands of volts before the power is pushed through transmission lines. When you flip a switch in your house, you allow current to flow into whatever device is “requesting” power, thereby utilizing some small portion of the total energy on the grid. Now, if there were 10,000 people trying to turn on their clothes dryers simultaneously, the system will likely not be able to keep up. More power stations could come online, but the instantaneous need would instead likely cause blackouts and brownouts to occur, leaving customers without power. So what they do is try to curb everyone turning on their clothes dryer at the same point every day by charging a lot of money for using the power then. They say, “Why not run the dryer at night? We’ll make it worth your while!”. The Smart Grid/Trainer is there to try and balance the needs of the consumer and the ability of the power generators. It will hopefully save people money and allow power generation facilities to avoid turning to readily available energy (coal, natural gas) to fulfill the demand.

A smart grid has a potential to bring a lot of engineering jobs, especially in waning job markets such as the US. I plan to write more about the Smart Grid because I truly believe it will bring some innovation and employment to whoever jumps on the technology first. There are a lot of pieces to the eventual solution–some more interesting than other–but all deserve analysis and consideration in determining what will result in the most efficient eventual system.

Do you know much about the Smart Grid? Have you experienced any development or funding activities for it yet? Please let us all know in the comments!

Thanks to exfordy for the photo

Categories
Engineering House Life

Energy Consumption Improvements in the House

Now that we’ve made it through a bit of the summer, I think we really need to focus on something important.

Winter is on the way!

If I recall correctly, my home is still not quite up to snuff in terms of how much money I’d like it to cost me to heat and energize my house. I realize my home will never be 100% efficient. I also realize I’m not going to plop down money to get to 100% because that’s silly and sort of impossible. Instead, I have to pick my battles with my own castle and decide what will produce the biggest returns.

  1. Insulate
    • This is the number one project for the late summer/fall for me. I have very poor insulation in my upper floor. In fact, when we bought our house we could actually see the snow melting on the roof where the heat was escaping. Talk about watching your money fly out of your pocket! Check with a local contractor to see how much insulation you’ll need to really see some energy savings. Also, don’t forget the federal credit when you’re finally cutting that check…you could get up to a $1500 tax rebate.
    • But wait…there’s more! Don’t think that whole house insulation is the only thing to focus on. Oftentimes, the biggest culprits of letting expensive, hot air out (or in really) are the small cracks around windows and doors. Spending 40 bucks on some expandable foam, a tube of caulk, a water heater blanket and some new winterizing doorstops can go a long way.
  2. Turn it off
    • There’s no denying that the most effective way to cut energy consumption is by turning devices and lighting off when not using it. This idea, coupled with using energy when it is cheapest and most abundant, is the crux of the “smart grid” idea. For devices that aren’t managed by a central management unit such as the one in the article, most devices now have a “sleep” mode that has reduced processing instructions; the device periodically “wakes up” to check to see if anyone has requested its services and if not it’s back to sleep. Devices with low quiescent current (or the current while not doing much of anything) can show large energy consumption savings.
  3. Buy/Replace
    • Even though people probably don’t relish the idea of throwing away (or hopefully recycling) their old appliances, this is sometimes the best option. Your old freezer in the basement might be saving you trips to the grocery store (good) but might be doing it at the environment’s and your expense by increasing your electricity bill(bad). Pick up a Kill-a-Watt meter to see how much power your old junker is really pulling out of the grid; if it’s considerable, think about pulling the plug.
  4. Inspect your ductwork
    • Oy, with the not-electronics already! I know, it’s not glamorous, but it’s often the simple things in houses that can really cost you. This is a big weakness in my house and something I will have to address before this winter. Back in the 50s and 60s they must have thought it fashionable (or at least cheap) to attach boards to the underside of the crossbeams of my floors. As such, the air actually being pulled down through the cold air returns is minimal, most of the air is actually pulled down through the floorboards and back into the cold air intake of my furnace. It’s a good time in the summer to check out where your ducts are leaking air so that you can save big dollars in the winter months.
  5. Junk Water Dump
    • I saw an article a while back about the waste water from your tub also wasting energy. Think about how much natural gas/electricity it takes to get your water heater to temperature. Now think about how warm the water still is when it’s washed away all the nasty off your body. Finally, think about how cold the tap water can e in the winter. If you have a reservoir underneath your tub collecting warm wastewater and then coil the incoming cold water through it on the way to the water heater, you could possibly retain some of that usually wasted energy. Check out the link and check to see if you ever have that kind of option the way your house is set up. This could be the same for the dishwasher and the washing machine while the water is on “warm”.

I know you’ll see a lot of this information elsewhere but I’d feel silly not to encourage readers here to try it out for this coming winter. As I said above, there are many different monetary incentives to do so, both in rebates and power savings. I plan on getting the jump on these updates now so I can take advantage of the energy savings for cooling my house as well as heating it later on. If I find out about or come up with any other ways to save money and energy in the future, I’ll be sure to post them here.

What about you? Have you decided to do any updates to your home (energy-wise) while the weather is still nice? Do you have any tips you’d like to share? Just leave them in the comments!

Categories
Politics Renewable Energy

Thank You Steven Chu

I like it when I understand things. The universe feels like a little safer place, even if I realize feeling secure is only a state of mind. And when I watched Steven Chu talk on the Daily Show the other night, I felt safer. Not like a warm security blanket kind of safe. More like a “Hey, if stuff hits the fan, we’ll probably be able to figure it out” kind of safe.

How many times have you looked at a government official and said “Hey, they seem pretty bright!”? How about “What a great sense of humor and perspective for the situation we’re in.”? How many times have you honestly said in the past 8, 16, 20 or 28 years have you really looked at a government official and said “Hey, I bet he has science and the earth’s best interest ahead of a corporation that is whispering in his ear.”? Not too many at all.

I’m not saying that there have been scores of corrupt politicians in the past Presidents’ cabinets, because there haven’t; the people advising the President are often capable and well tempered in their decision making. I’m also not saying Steven Chu will be completely successful in the political arena, as it’s a very different world from what he’s used to. It’s just so damn refreshing to see such an accomplished scientist in a position to influence legislation, all the while weighing facts and data instead of political usefulness and opinion. Give me more politicians like him and I’ll start to feel that the government has turned a corner.

So thank you, Steven Chu. You’ve restored my hope that we can get some more renewable energy initiatives moving instead of just talked about in this country. You’ve restored my hope that renewables might be able to help pull our country out of a recession. And from what I know about you and your plans, you’ve only just begun.

The Daily Show With Jon Stewart Mon – Thurs 11p / 10c
Steven Chu
www.thedailyshow.com
Daily Show
Full Episodes		 Political Humor Joke of the Day


Also the requisite thank you to Comedy Central and Jon Stewart for interviewing him. Without you, I’d only get biased news from biased news sources 🙂

Categories
Learning Work

Who Will Do The Actual Work When The Economy Recovers?

I had an interesting conversation today with a few friends about the exodus of young people from the workplace back to school during this recession. It seems as though people in Generation Y are bailing left and right on current jobs and diving back under the safe covers of academia. And who can blame them? You get to work on interesting research (hopefully), you get a stipend (maybe) and you have better prospects when you’re all done (eh, doubtful). But that leads me to ask, “Who’s going to do all the work when the economy is in full swing again?” Let’s survey the current demographics, starting from the top:

  • The bosses — Not to sound deriding, but they aren’t doing the type of work I’m talking about here. The never have and never will…mostly because they actually have better things to do. For real. They have to meet with other big wigs and figure out where to steer the company and where the market is going and hopefully how to react in time. The work I talk about is more a “down-in-the-trenches” kind of work and I never really expected them to do that kind of work, just thought it was necessary to actually start at the top.
  • The elders — The elders are those who aren’t necessarily in charge but those that have been around for a long time and really understand how a company or industry works. They won’t be doing the work when the economy recovers…because they’ll be retiring. Think about it. How many people were likely planning on retiring in 2008 onwards who suddenly saw their investments vaporize? No, they decided they better stick it out. And though they won’t see a huge return to the days where their portfolios were bulging, I would venture a guess that if the conditions are good enough and they feel that they can squeak by on portfolio growth after they retire, a lot will take the out. If you’re pushing into your 70s, I’m guessing you’re ready for a break. Even if they stay on part time, they won’t be doing the grunt work.
  • The smart ones — The smart ones are those that drive ideas and new products. Even though they may have been around and producing good work for a while, they aren’t allowed to go anywhere. They are the geese with the golden eggs. Where would they go anyway? The people in charge of promoting them would have to replace themselves. Not likely. So they will have to do some work still, but you can probably watch for this group eying the social security line on their weekly pay stub longingly and starting to stick a pinky toe out the door. If you’re looking for a technical mentor, get ’em before they’re gone.
  • The middle — The middle is all those people that were doing the grunt work 20 years ago and did a good job. They may have run out of salary headroom and jumped over to management or maybe they needed a new challenge (I can only imagine dealing with engineers or other similar underlings from a management perspective every day). Either way, there’s little likelihood they’re planning on stepping back into lesser roles. No, they have their eyes on the upper management jobs of the elders and the other aging boomers.
  • The lazy ones — They were the ones on the team that did work every once in a while but in general only contributed when the workload really picked up. They were the auxiliary fuel tank of your company as an airplane–useful when you need it but really just weighing things down when not in use. And although we know it’s not really true, we have an inkling some of them got the ax when it fell last year. Even if you were deluded enough to believe that all the dead weight in your company was gone, the ones in this category that aren’t gone are really good at two things: not doing work and looking like they are. Count them out.
  • The young upstarts — This group has a shot at doing some of the beefy work. In fact, this group has the highest likelihood of doing the majority of the work. I should mention I also feel as though I am a part of this group and therefore have a lot of interest in studying it. “What’s that?? Jim, Allison and Mark are all going back to school? Why? Trudy is going too? What the heck? Who’s going to do their work?!?”, you say (the answer: whoever is asking that question). This newfound love of the classroom is the other reason I am interested in my own demographic. We’re all jumping ship hoping to leapfrog into the next part of our career! There doesn’t seem to be any paying of dues, does there? Welp, that’s because there isn’t. But you can’t do anything about it because everyone in this demographic is back in classes learning about managerial accounting or tort law and not actually doing any work. Now the real question: when everyone pops out of school at the end of the recession, who will be better prepared? MBA Marty or Experienced Eddy? I’d be inclined to say the second, but again, I’m biased here. If you’re in this group and not going back to school, expect more work coming your way. Lawyer Larry is busy studying.
  • The new grads — Quick! We’re running out of people that have any interest in engineering and menial tasks! Get me some workers! “Waaaaaait a second,” says Bob the manager. “All we’ve got is the new grads. There’s no way I’m hiring them without any experience.” Well Bob, too bad, you’re running out of options. Just hire these new kids and try and push them to learn faster and work harder. And do this even though those new grads have higher expectations of what employers will give them and the hours they are asked to work. You’ll probably end up giving it to them too, because what other options do you have?
  • The overseas workers — Well, there’s your answer. It’s really been more of a circular process, figuring out who will be doing all the work. Think about what’s been said and how people have reacted. “Foreign labor is taking all of our jobs!”, the workers said at the beginning. Then they thought, “Oh! I better go back to school and learn how to manage people overseas and the remaining labor in the US!”. Then they get out of school three years later, lobby for a shiny new management position and ask “Ok, where are my underlings? Hunh? No underlings?!? Well crap, hire more foreign workers, we need to get this project out the door!”. Lather, rinse, repeat.

I want to be clear about a few things. First, I don’t disagree with going back to school. I plan on doing it myself some day, in some capacity. I just disagree with the timing. I liken going back now to pulling all your investments out of the market at the lowest point back in March (maybe to pay for school?). You remove yourself from the market at a time when the most growth can occur. You remove yourself from situations that include working long hours on hard work but it’s with a team that affords you more responsibilities. I feel that the next few years will provide some great opportunities for innovation and growth in certain positions and companies. Second, I realize that some people are going back to revamp skills, especially when they feel that they cannot find employment. This is understandable and expected based on enrollment numbers from past recessions. I would only remind these people to remember to keep up their real-world skills so they can be hired right out of school. Academia doesn’t have room to hold onto you and they have a similar hierarchy as above except for one catch: those tenured professors don’t plan on giving up their cushy position until they are forced to or decide to leave on their own. If you do choose the academic track, get a comfy couch to wait/sleep/eat/live on. Finally, I’d like to speak to my targeting of MBA and Law degrees. It’s not that I think they aren’t important, because I feel that a lot of really important concepts are taught in both management and law classes. I mostly take offense to the idea of you being my boss in 5 years because of a piece of paper. I respect the people around me who are working hard and have better vision than I do to tell me what to do. If you plan on “managing” me without first working by my side or in a similar position, expect to work extra hard to gain my respect.

I believe the solution here is what a lot of people are actually doing: sitting tight and getting some work done. You need to continue to show your company you are a valuable and contributing member while maintaining boundaries on how many peoples’ work you are willing to do. It sometimes seems bleak when you see others stagnating in their career progression right in front of or next to you. However, I believe hard work and tangible results will be the true indicator or advancement and success whenever the economy rebounds. If you think your hard work should go towards a more noble cause, strike out on your own. If companies end up short on talent when the economy comes back, a savvy consultant could be flexible and fluid enough to be exactly the solution customers and companies are looking for.

What about you? What category do you feel like you fall into? Take the poll below or leave a note in the comments!

[poll id=”3″]

Categories
Analog Electronics Engineering Work

When to Try Something vs When to Study Something

Irony is having a blog post in your queue with a title such as this one and just sitting on it for weeks on end. Luckily I’ve been trying some things instead of studying them, it just so happens that those things have nothing to do with this site. I hope to discuss those on this site soon.

I am a glutton for knowledge.  Part of it is my fear of looking silly in front of co-workers when I don’t know the answer to something. Part of it is feeling like my knowledge base is lacking and the thought that I can always learn or teach myself something new. But when presented with a new challenging situation that requires you to learn the question is always the same: where do you start? Do you jump in and try it out? Or sit back and study what others have tried so as to not duplicate their mistakes?

There are two extremes

  1. You study so much and try to take in so much that you become paralyzed by information
    • I feel like this happens to Generation Y more than other generations. Not because we are dumber than others. Instead, I think we are so accustomed to having all of the necessary knowledge required to solve a problem at our fingertips (i.e. Internet, ChrisGammell.com, etc).
    • Academic thought processes often begin with simplistic assumptions about the model you’re considering. Analyzing these over and over can be very time consuming and can quickly become too complex to handle. Even analyzing the minutiae associated with a single transistor can be mind boggling. What happens when you try and expand that knowledge to 10, 10k or 10M transistors?
    • You over simulate, over analyze, over think a problem past the point of diminishing returns. An example would be designing a new type of toothbrush. You can model the toothbrush, the bristles, the handle, the shapes, everything; you can even go out and get ideas from your toothy customers about what they think they would like or dislike about your design. But until you prototype your new type of toothbrush and put it through testing (product testing, tooth scrubbing ability, will it shatter in someone’s mouth), then all of the testing and surveying in the world won’t matter.
  2. You have little knowledge of a problem or situation that you just start changing stuff randomly and keep changing until something works…without realizing the consequences.
    • This seems to be the modus operandi of the inexperienced, but not necessarily the uneducated. A gutsy, recently graduated electrical engineer may emerge from the cocoon of the academic environment ready to go out and change the world. And every resistor value of a circuit board they encounter. And mess with the capacitors. And change the model of the op amps. Oh, and don’t forget to swap out transistors. “What?? It still doesn’t work? But why?”
    • This can be as much a symptom of engineering bravado as it is bad conditioning. If the person involved has always had simple problems placed in front of them that have obvious or at least semi-obvious solutions (ahem, most introductory electronics labs), they will fix the “broken” component and pat themselves on the back. In the real world, that “broken” component isn’t broken at all. It’s just out of spec and you can’t figure out for the life of you why that unit you’re testing refuses to turn on anymore after increasing 5 degrees internal temperature.
    • You forget/refuse to read the manual. Granted, some of the greatest “tinkerers” out there can just magically turn a knob and get a broken piece of equipment to work. But the reason they can do that is because they actually turned the wrong knob about 1000 times the last time they tried to fix something like this and that knob did absolutely nothing.

A Good Mix (for me, at least):

[STUDY] My own personal mix when it comes to circuit problems starts with the problem definition. Understanding the problem is so much more important than what you study, how long you study it or how you begin to test out your ideas for how to fix it. If you don’t understand what the real problem is all that later work is for nothing! However, I try to understand the issue without going overboard and trying to understand every single minute detail; this could be just as bad as studying a possible solution for hours on end.

[TRY] Once I have a grasp on what the problem is, I try the obvious stuff. You’d be surprised how often it can be the really dumb things that trip you up. And those might not even be the problem you’re trying to fix. You could try to troubleshoot a blank screen for 20 minutes, throwing your best ideas and debugging techniques at it before you realize, “Whoops!” you never plugged in the display cable. Or you can’t get your software to work once you load it onto your electromechanical whizzbang toy…but you actually loaded the wrong version of the software or the toy doesn’t have any batteries in it. The silly things will waste your time and throw you off the trail of the real problem if you’re not careful.

[STUDY] Next is researching the problem to see if it has happened before. Some of you out there will have unique situations, like making a new analog chip that no one has ever made before. But I’d guess more of you will be encountering problems that can be researched. Even the analog chip designers will see issues that are similar on some level to other products or models within a corporation. Oftentimes the best troubleshooters are those who are able to compartmentalize problems and then analyze where those problems came from and research how others have fixed it in the past. I’d rather have a boring problem that someone else can easily tell me how to fix than one that I can’t figure out at all.

[TRY] After trying and then studying all of the really obvious stuff, I start to go back to my resources–either online or in print–and start to search for information on the topic. Obviously the online information is much easier to search, but I also have some trusted books that I turn to on a regular basis. I might see a chunk of a circuit that looks familiar and try flipping through the pages to see if I can’t find a similar circuit. If that doesn’t work or the circuit looks extremely foreign to me, I’ll go back and study some of the basic properties of the components within the circuit to see if there might be a certain property the designer used that I have overlooked. And if all else fails, I’ll start to ask around to try and gather others’ knowledge of the circuit. True, this isn’t quite studying, but can often be more effective. I try and balance asking others for assistance only after I have tried to solve the problem on my own and not made any progress. I think it is important for my personal growth to struggle with a circuit before asking for help and I think it’s important to not get in the habit of running off and asking for an answer so I don’t waste the other person’s time. However, I don’t want to be so stubborn that I waste my time and the time of those who are paying me.

[STUDY] Alright, so now you know what the circuit is and how it sort of works. But you also know that you need to change the circuit in order to make it work better. What now? Next I would try and write out any equations I know that are relevant to the circuit. Not necessarily any equation, that could end up being a waste of time. Keep it simple and make sure you know where the currents and voltages are in different parts of the circuit. If there are components (such as capacitors) in the circuit, include basic equations that can help to describe their behavior. If you don’t need 3 chalkboards to do so, try and figure out the transfer function (relationship from input to output). If you have a circuit that is too complicated either break it down into smaller pieces and try and figure out the transfer function or take the plunge and try it out in SPICE. This will help you to better understand how the circuit might behave when presented with certain inputs. All of these exercises are done in order to present you with a solid starting ground for when you actually construct the circuit, so you know what to look for and what behaviors to expect.

[TRY] After all of the studying and simulating and pondering about this circuit, you should have at least enough knowledge to begin building up and trying the circuit. This is an important step in any circuit creation process because of the nuances the real circuit will show you. Perhaps you forgot to model a realistic op amp in your SPICE simulation and it was outputting 500 A. Perhaps you didn’t realize in your equations that a resistor will have different properties depending on how much current you actually put through it and that your circuit happens to be particularly susceptible to those changes. Perhaps you completely disregarded a simple concept such as bandwidth and your circuit is now oscillating so hard it breaks. All of these things will be uncovered when you begin to build up your circuit and try out different inputs. Once you realize what some of the realistic problems are you can go back and modify your assumptions and models and start to delve into whatever topics you believe will get your circuit to the optimum operating point.

Finding the right balance between slowing down and taking your time to figure out a circuit or jumping in and seeing what works can be a fine art. Sometimes projects are on a very tight schedule and need a product cranked out the next day (think startup). Sometimes you have one shot at making a final product or else your company will fail (think chip fabrication). Finding your own personal mix will take time and trial and error.

What is your personal mix of trying vs. studying that gets the best results? Leave your tips and tricks in the comments!

Categories
Analog Electronics Engineering Learning

Where Will I Use This Electrical Engineering Stuff?

I find myself sitting around these days trying to catch up on knowledge I feel like I missed in school. Worse, I feel like I learned it at one time but it all fell out the other side once I took the exam. Pretty standard really, when you don’t think you’re going to need to the knowledge some day. Haven’t you ever sat in class wondering if you’d really ever use the material you were expected to learn? How much did you pay attention?

I feel that a requisite of every college class should be at least an entire class devoted to how you can use the knowledge contained in the remainder of the course material. It should probably happen close to the beginning of the semester or quarter. I have always lobbied for this kind of explanation and have always tried to include it whenever I am teaching something. Better yet, if someone from the field come in and explain how they use the knowledge in their working lives it would really drive the point home. When you know that you will definitely use certain knowledge, you’re more likely to sit up and pay attention.

Some of the material that I have been relearning lately has been tangential to the actual material we covered in classes back in my school days. Some of this is because I needed to go back and re-learn the absolute basics, such as semiconductor physics. I didn’t quite need to learn why a PN junction behaves as it does, only how it behaves and how it relates to larger devices such as transistors (basically a couple PN junctions specialized for certain behavior and placed in a certain configuration). I also don’t need to know why certain materials carry magnetic fields, only how they do and how you can use them to build a transformer. Other than re-learning the absolute basics, it’s driven by things I encounter in my daily work where I feel I was lacking. Very general topics but things that have very specific application in my job. Transformers are an area where I felt it was necessary to get more info, so I used my favorite resource (OhioLink) to get some textbooks based on co-workers recommendations. Hey, you just end up reading the textbook in some classes anyway, right? So why not?

So I guess that’s all I have to say about this topic. If you don’t know something, go to the library and and figure it out (I love libraries). And if books don’t show you what you need, ask a friend. Most importantly, find out where you might use the material you’re learning the first time you see it. If you’re not being directly told why you will need a certain piece of information, do the legwork yourself and figure out why you should care (someone saying “because it’s in the course outline” isn’t good enough). The application of the knowledge is much more important over the long term.

Got something you can’t figure out? Ask me in the comments.

Categories
Analog Electronics Digital Electronics Life Politics

The Digital Switchover and Why It’s About People

The Digital Switchover.

Not me. I almost did that a while back, but no. Not me.

Television.

Normally I wouldn’t write about it. A digital television standard is long overdue and in the end this will be a good thing. When you compare Analog vs Digital, there are many more benefits on the digital side of things: lower power for transmission, better bandwidth of signal, more bandwidth usage over the spectrum. All of these are good things. I can even talk about how those digital signals still have lots of analog components as they’re transmitted over the airwaves: multipath, signal loss, power calculation, reception problems, etc.

But no. I’d rather point something else out:

Technology adoption is driven by human nature. It must be adopted before it can help people.

Sure, the digital signals will be great. High Definition pictures and you don’t have to give a dime to those lovely cable companies. Lower power generation required to transmit the signals will help save the environment by lowering the carbon footprint. But until the switch actually happens (today…maybe), no one gets the benefits. The switchover has been delayed to now from this past February. Lawmakers deemed the country unready to make the switchover at that time. I mean, if people can’t watch TV, how will the politicians get their message out to the masses?

No matter how many new devices are introduced into the marketplace and no matter how available they make DTV switcher boxes, people still will not change until pushed. They will not go out and get the digital box or call their local politician until one day they turn on their television and the signal is not there. That is what will drive the final changeover. I wouldn’t be surprised if we saw a little bit more leeway from politicians before stations are officially told to shut off the analog transmitters.

This problem isn’t exclusive to television. This has happened for the past 30 years in conservation and renewable energy.  Regardless of how many times climate change experts point out we’re killing the planet, nothing moves until there is a scare that oil is running out (it is) or natural gas won’t always be available (it won’t) or coal is filthy (it is) or the power just goes out. Then people change their tune; they change gears and start thinking about buying that solar array or that home wind turbine. They start recycling again because they think it will start to help (it will, but what about the past 10 years of bottles you put in the landfill?). But the thing is, you need to think about buying the solar cells now, when there isn’t a 6 month backlog of installation requests and prices are jacked up due to demand. And Solar might even already be an affordable option for you.

I’m sure people will say there’s an economic aspect of it for DTV and that the people that use analog signals the most can’t afford the converter boxes. Perhaps that has some truth to it. But the point remains that no matter the technology, until that last group resistant or indifferent to change decides to go out and do something about it, those people can’t be helped.

What about you? Have you made the switchover yet? If not, why? Leave a note in the comments.

Categories
Analog Electronics Music

Co-workers Bring New Projects

One of the best parts of working with others interested in electronics is having similar hobbies: namely, electronics and music.  And even though I have similar hobbies, I never really brought them up in conversation with co-workers (believe me, some of the stuff I have done pales in comparison to some of the people I work with). However, in the past few weeks it has really paid off talking about my non-work work, both for my personal hobbies and for things to write about that interest me.

Tektronics 425M Oscilloscope:

A few months back I had mentioned how I blew up my Wurlitzer 200 and needed to start troubleshooting it for possible problems. I also lamented the fact that I didn’t have a scope to look at waveforms when I finally got the DC characteristic where I want them. Fast forward to a few weeks ago and a friend and co-worker mentions that he had a scope that he had purchased on eBay but was DOA. Apparently it broke in the midst of shipping and he didn’t get charged by the seller. He also bought a working scope later and intended to fix this one, but never got to it. As such he was clearing out room and offered it to me, a truly generous offer.

The scope itself is a dual channel, 100 MHz scope. It is a military version of the scope so it possibly has better spec’d parts (but I haven’t looked into this  too much).The main problem is that the beam does not render any images onto the phosphorescent screen. Other than that, it is supposed to work fine. Time will tell on the other components.

The interesting  thing about the older analog scopes is that many of them can be repaired by non-professionals. More accurately, they can be repaired by individuals not employed by Tektronics because the schematics are available, the components are large enough to replace quasi-easily and there aren’t proprietary ASICs you have to order from the OEM. One notable fixer-upper of all old things Tektronics is Jim Williams, applications engineer for Linear Technologies and electonics writer (my favorite thing about him is that he lists his 84 Tek scopes at home when he writes his own bios at the end of books or articles). All of these things lead to some analog engineers being die-hard fans of analog scopes. They also like that analog scopes never introduce sampling errors or glitches. This is less and less of a problem with new digital scopes on the market and yet the analog vs digital battle rages on (at least in my mind).

Oscilloscope

Oscilloscope

Goals/Projects:

  1. Get the front panel working
  2. Use it to troubleshoot any remaining hum and sound issues on the Wurlitzer 200
  3. Use it to aid me in creating a simple waveform generator (perhaps a buffered output from a computer?)
  4. Use it to troubleshoot issues that arise with the organ and other projects surrounding it

Hammond M3 Organ:

Another co-worker and I were discussing music one day and I mentioned my work on the Wurlitzer. He happened to mention how his wife would be very pleased if he would sell their organ; I was similarly pleased. I’ve been a fan of Hammond Organ in Soul Jazz and Jazz music (thanks Evan and Trevor) a while longer than I’ve been collecting the instruments used by them (thanks Noah).

The organ came to me in good shape sound wise; a little bit of hum but all of the keys are in really good shape and the drawbars work great. No Leslie speaker for now but the person who sold it to me says he might be able to sell me his model 900 eventually. I will also try and get one on my own in the mean time to see if I can’t get a better model (Model 122 or 145). The cosmetic condition of the organ is poor but I don’t think it would have as much character if the thing was squeaky clean. I also plan to possibly chop the organ at some point (put it into a smaller, transportable case) so the cosmetics don’t really matter.

Hammond M3 Organ Side

Hammond M3 Organ Front

Goals/Projects:

  1. Get the organ oiled and hum-less
  2. Successfully replace and re-bias the tubes on the main amplifier
  3. Build an external amplifier and cabinet to increase the sound output
  4. Create sound effect pedals to modify the sound output of the organ to my liking
  5. Document the internals of the tonewheel mechanism
  6. Chop the organ into a transportable case (less than the original weight of 250 lbs)

So these are some of my projects for the summer and possibly extending beyond into the rest of the year. I really look forward to working on two pieces of spectacularly engineered equipment. While I won’t be redesigning the equipment or doing much beyond touching up some of the worn out components, I hope to learn from the internals of these pieces of equipment and use them in future projects.

Do you have any ideas to build off of what I have listed here? What kind of projects are you working on this summer? Let me know in the comments!

Categories
Analog Electronics Digital Electronics Engineering

The Future of Troubleshooting

If you are an engineer who regularly works with your hands, you likely troubleshoot on a daily basis. It’s just part of the job. Sure, you can say, “I never mess up!”, but hardly anyone will believe you. Because even when your best laid plans go perfectly, Murphy’s Law will soon kick in to balance things out. We learn to deal with these things and have developed tools and measurement equipment to help us diagnose and deal with these problems: Multimeters, Electrometers, SourceMeters, Oscilloscopes, Network Analyzers, Logic Analyzers, Spectrum Analyzers, Semiconductor Test equipment (ha, guess I know a little about that stuff)…the list goes on and on. But what has struck me lately has been that as parts on printed circuit boards get smaller and smaller, troubleshooting is getting…well….more troubling.

  1. Package Types — I don’t want to get into another discussion of analog vs digital, but I will say that digital parts on average have many more pins which complicates things. And as the parts get more and more complex, they require more and more pins. The industry solution was to move to a Ball Grid Array package, using tiny solder balls on the bottom of the chip that then line up with a grid of similar sized holes on the board. When you heat up the part the solderballs melt and hold the chip into place and connects all of the signals. The problem is the size of the solderballs and the connecting vias: they’re tiny. Like super tiny. Like don’t try probing the signals without a microscope and some very small probes. But wait, it’s not just the digital parts! The analog parts are getting increasingly small to accommodate any of those now-smaller-but-still-considerably-bigger-than analog parts. You thought probing a digital signal was tough before? Now try measuring something that has more than 2 possible values!
  2. Board Layers — As the parts continue on their shrink cycle, the designers using these parts also want to place them closer together (why else would they want them so small?).The circuit board designers route signals down through the different layers of insulating material so that mutiple planes can be used to route isolated signals to different points on the board. So to actually route any signals to the multitude of pins available, more and more board layers are required as the parts get smaller and closer together. Granted, parts are still mounted on either the top or bottom of the board. But if a single signal is routed from underneath a BGA package, down through the fourth layer of an 8 layer board board and then up to another BGA package, the signal will be impossible to see and measure without ripping the board apart.
  3. High Clocks — As systems are required to go faster and faster, so are their clocks. Consumers are used to seeing CPU speeds in the GHz range and others using RF devices are used to seeing even higher, into the tens of GHz. The problem arises when considering troubleshooting these high speed components. If you have a 10 GHz digital signal and you expect the waveforms to be in any way square (as opposed to sinusoidal) you need to have spectral data up to the 5th harmonic. In this case, it means you need to see 50 GHz. However, as explained with analog to digital converters in the previous post, you need to sample at twice the highest frequency you are interested in to be able to properly see all of the data. 100 GHz! I’m not saying it’s impossible, just that the equipment required to make such a measurement is very pricey (imagine how much more complicated that piece of equipment must be). High speed introduces myriad issues when attempting to troubleshoot non-working products.
  4. Massive amounts of data — When working with high speed analog and digital systems there is a good amount of data available. The intelligent system designer will be storing data at some point in the system either for debugging and troubleshooting or for the actual product (as in an embedded system). When dealing with MBs and even GBs of data streaming out of sensors and into memories or out of memories and into PCs, there are a lot of places that can glitch and cause a system failure. With newer systems processing more and more data, it will become increasingly difficult to find out what is causing the error, when it happened and how to fix it.
  5. Less Pins Available out of Packages — Even though digital packages are including more and more pins as they get increasingly complex, often times the packages cannot provide enough spare pins to do troubleshooting on a design. As other system components that connect to the original chip also get more intricate (memories, peripherals, etc), they will require more and more connections. The end result is a more powerful device with a higher pin count, but not necessarily more pins available for you the user/developer to use when debugging a design.
  6. Rework — Over a long enough time period, the production of  printed circuit boards cannot be perfect.  The question is what to do with the product once you realize the board you just constructed doesn’t work. When parts were large DIP packages or better, socketed (drop in replacements), changing out individual components was not difficult. However, as the parts continue to shrink and boards become increasingly complex to accommodate the higher pin counts, replacing the entire board sometimes becomes the most viable troubleshooting action. Environmentally this is a very poor policy. As a business, this often seems to be a decent method (if the part cost is less expensive than the labor needed to try and replace tiny components) but if and when the failures stack up, the board replacement idea quickly turns sour.

While the future of troubleshooting looks more and more difficult, there have always been solutions and providers that have popped up with new tools to assist in diagnosing and fixing a problem. In fact, much of the test and measurement industry is built around the idea that boards, parts, chips, etc are going to have problems and that there should be tools and methods to quickly find the culprit. Let’s look at some of the methods and tools available to designers today:

  1. DfX — DfX is the idea of planning for failure modes at the design stage and trying to lessen the risk of those failures happening. If you are designing a soccer ball, you would consider manufacturability of that ball when designing it (making sure the materials used aren’t super difficult to mold into a soccer ball), you would consider testability (making sure you can inflate and try out the ball as soon as it comes off the production line) and you would consider reliability (making sure your customers don’t return deflated balls 6 months down the line that cannot be repaired and must immediately be replaced). All of these considerations are pertinent to electronics design and the upfront planning can help to solve many of the above listed problems:
    1. Manufacturability — Parts that are easy to put onto the board cuts down on problem boards and possibly allows for easier removal and rework in the event of a failure. It becomes a balancing act between utilitizing available space on the board and using chips that are easier to troubleshoot.
    2. Testability — Routing important signals to a test pad on the top of a board before a design goes to the board house allows for more visibility into what is actually happening within a system (as opposed to seeing the internal system’s effect on the top level pins and outputs).
    3. Reliability — In the event you are using parts that cannot easily removed and replaced and you are forced to replace entire boards, you want to make sure your board is less likely to fail. It will save your business money and will ensure customer satisfaction.
  2. Simulation — One of the best ways to avoid problems in a design is to simulate beforehand. Simulation can help to see how a design will react to different input, perform under stressful conditions (i.e. high temperature) and in general will help to avoid many of the issues that would require troubleshooting in first place. A warning that cannot be overstated though: simulation is no replacement for the real thing. No matter how many inputs your simulation has and how well your components are modeled, no simulation can perfectly match what will happen in the real world. If you are an analog designer, simulate in SPICE to get the large problems out of the way and to figure out how different inputs will affect your product. Afterward, construct a real test version of your board or circuit and make sure your model fits your real world version. By assuming something will go wrong with the product, you will be better prepared for when it does and will be able to fix it faster.
  3. Very very steady hands — Sometimes you have to accept the fact that you messed up and the signal traces on your board and you have to rewire it somehow. My analog chip designing friends needn’t worry about trying this…chips do not have the option for re-wiring without completely reworking the silicon pathways that build the chip. In the event you do mess up and have to try and wire a BGA part to a different part of the board or jumper 0201 resistors, make sure you have a skilled technician on hand or you have very steady hands yourself. And in the event you find yourself complaining about how small the job you have to do is, think of the work that Willard Wigan does…and stop complaining.
  4. On the Chip/Board tools — Digital devices have the benefit of being stopped and started at almost any point in a program (debug). Without being able to ascertain what the real world output values are though, it doesn’t help too much. If in the event you do not Design for Test and actually pull signals you need to probe to the top level then you create a board then there are a few other options. One option is to try and read your memory locations or your processor internals directly by communicating through a debugger interface. But if you are looking at a multitude of signals and want to see exactly how the output pins look when given a certain input there is another valuable tool known as “boundary scan”. The chip or processor will accept an interface command through a specified port and then serially shift the values of the pins back out to you. Anytime you ask the chip for the exact state of all the pins, an array of ones and zeros will return which you can then decode to see which signals and pins are high or low.
  5. Expensive equipment — As mentioned above when describing an RF system measurement needs, there will always be someone who is willing to sell you the equipment you need or work to create a new solution for you. They will just charge you a ton for it. In cases I have seen where a measurement is really difficult to calculate or you need to debug a very complicated system, the specially made measurement solutions often perform great where you need them, but are severely limited outside of their scope. To use the example from before, if you needed a 100GHz oscilloscope, it is likely whomever is making it for you will deliver a product that can measure 100GHz. But if you wanted that same scope to measure 1 GHz, it would do not perform as well because it had been optimized for your specific task. However, there are exceptions to this and certain pieces of equipment sometimes seem like they can do just about anything.

Debugging is part of the job for engineers. Until you become a perfect designer it is useful to have methods and equipment for quickly figuring out what went wrong in your design. Over time you become better at knowing which signals will be critical in a design and planning on looking at those first, thereby cutting down on the time it takes to debug a product. And as you get more experience you recognize common mistakes and are sure not to design those into the product in the first place.

Do you know of any troubleshooting tools or methods that I’ve missed? What kinds of troubleshooting do you do on a daily basis? Let me know in the comments!

Categories
Analog Electronics Digital Electronics Engineering

When To Use Analog Vs. Digital

Analog. Digital. Continuous. Discrete. Choices abound.

Well, not really.

In reality you will deal with both kinds of signals when working on just about any electronics these days. A simple example is in a switching regulator. These devices are meant to take input power from a wall plug or something providing a relatively constant voltage and then the regulator will ensure that the voltage is always the same when leaving. Internal to the circuit, a “digital” signal (on or off) determines when to let in incoming power go from the input to the output. The “digital” signal translates into an “analog” voltage at the output, hopefully the voltage you programmed.

From there, systems become increasingly complicated, translating real world data to digital format, processing the digital data and spitting it back out again. The guts of the systems have infinite internal combinations and options, but in the end just about every hybrid system looks like this:

ad_system

The remainder of this post will be devoted to explaining situations that are either contained within the above system or situations that benefit from looking nothing like it; some of these situations mandate analog or digital implementation but more importantly, some are best implemented as analog or digital.

To start, what is the definition of analog? We’ll consider it a continuous signal that has infinite bandwidth and complete spectral information. Analog in the context of this site usually refers to the circuitry used to operate on those continuous signals, but we also use the word “analog” interchangeably to describe the signals. Which situations are best suited to using analog components and circuitry?

  1. Continuous filtering — Filtering a signal is necessary when it has frequency components included that you do not want. Some filters are digital and are extremely accurate at removing one signal while retaining others (FIR). However, if you are dealing with a continuous signal and you want to filter ALL possible frequency content (and not be limited by the sampling frequency you used when converting to digital), then you need a continuous analog filter. There are many options available that can also help to push your filtering towards accuracies similar to digital filters but they become increasingly complex (multi-pole active filters). The main advantage to an analog filter here is that it is simple, less expensive (usually) and beyond your roll-off frequency you know that all information is being removed (whereas it might still be hidden in a sampled signal).
  2. Pre-A/D and Post D/A — Hybrid systems require both analog-to-digital converters and digital-to-analog converters to switch between continuous and discrete data. However, the sampling frequency must be at least twice the frequency of the highest frequency component contained within the signal, as explained by Nyquist’s Theorem. In order to ensure that the Nyquist Theorem is fulfilled, you can filter (see above) any signals that are inadvertently included in the original signal so that it does not create noise and artifacts after sampling. Since the signal is not yet digital, you HAVE to filter the signal with an analog filter (convenient, right?). Once you are done operating on a signal digitally and you convert it back to analog, all processing must once again be done with analog components and circuitry (see picture above). I usually think of an iPod after the signal has gone through the DAC. You need to control the gain (volume) and shape the frequency components (tone). Some post DAC activities can be done in the processor, but are often more efficient (read: cheaper) to do in simple analog components after the DAC.
  3. High power — While digital measurement and control is possible for high power systems, having a digital signal that switches between 0 and 400V would not be efficient. In either AC or DC systems, analog components are responsible for transforming and transmitting signals (although there may be digital control of those analog components at some point in the system). The continuous nature of power delivery mandates analog components that are well characterized and durable.
  4. Gain Control/Signal Conditioning — Say you want to measure the amplitude of a 4000 V signal. You decide that you want to use a computer to do so, so you shove your signal into an A/D converter. But wait, where the heck do you find an A/D converter that can convert a 4000V signal? Sorry, they don’t exist (yet). You instead have to condition the signal to fit into a range of 0V to +2.5V, or whatever is the input range of your specific ADC. You can do so with a simple resistive divider (passive, simple) or an inverting amplifier (active, more difficult).
  5. Control systems — While digital control systems are possible and are becoming more and more prevalent, analog systems can be simpler. One of the simplest examples is an inverting op-amp configuration. The load of the op amp is the plant, the op amp is the controller and the resistors are the feedback paths to the summing node. There are some delays in the system, but in general, the signal can handle a wide range of frequencies without complicated circuitry and the system can adjust to however the input changes. In a similar digital system, the feedback resistor would be replaced with an ADC, some kind of computing machine (microcontroller) and a DAC to convert the data back to analog to push into the summing node. The system is dependent upon the technology and speed of the components, whereas the analog system is dependent on resistors and the nature of the load (plant). Digital control systems are becoming more popular as DACs and ADCs become faster and more accurate but as of now, analog control systems remain simpler in some of the more common instances.
  6. Sensors — These devices are meant to help convert real world information that isn’t necessarily electrical, into a format that is recognizable by a computer or embedded system. Oftentimes these are not taking real world (analog) data and directly turning them into digital signals. Instead, the sensor (sometimes known as a transducer) first creates an analog signal that can later be converted. Converse to the high voltage systems, sensors are often very low amplitude and require some signal conditioning to increase the value of the signal to better utilize the full range of an ADC.
  7. Fidelity/Data loss — Some people just love analog stuff, especially when it comes to music. Even though audio systems containing ADCs and DACs are making very good analog equivalents these days, you will have to tear the record players and the tube amps out of the hands of the most die hard audiophiles. So instead of converting back and forth between digital and analog media, they prefer to keep the signal continuous all the way throughout the process. Starting from the air pressure variations emitted from Louis Armstrong’s trumpet that are then captured by a microphone and then amplified and pressed into a record, then touched by a needle and amplified again by a transistor or tube amp to recreate the sound as it is pushed out of your high end speakers. And even though there are processes to mathematically capture all of the data that is present to sample and perfectly recreate the original signal, some people won’t touch the stuff. Since I can’t afford the high end equipment audiophiles claim is necessary, I will sit on the sidelines for this argument. However, I enjoy that there is still so much interest in preserving audio fidelity in analog formats and don’t mind that it keeps analog engineers employed.

I feel a little silly explaining digital advantages because they seem to be flaunted at every opportunity by media and digital chip makers. Still, let’s go over some of the more important places to use digital as opposed to analog.

  1. Computing — Again, I know it sounds silly, but digital has emerged as the better way to compute numbers. How did they compute mathematical sums before the advent of the microchip and digital logic? Why, operational amplifiers of course! That is actually where the name comes from, since there are many different possible operations for incoming signals.  If you have two incoming signals, one at 2 volts and the other at 1 volt, you can: add them (summing amplifier), subtract them (differential amplifier), integrate them or differentiate them. While this can and still does work quite well on a large signal DC basis, using operational amplifiers in the computing machines today would be a bit unruly. Just to start the power usage and the offsets would pose enough problems to make you run out and buy ADCs, DACs and micro-controllers. If you have a big math problem to do, follow that urge. However, if you do have a simple math operation you need to do on two signals and you don’t want the overhead of a digital section, op amps can still do the trick nicely; with their fast reaction and the complete lack of sampling issues you won’t miss those ones and zeros for a second.
  2. Counting — In analog systems, counting can be a difficult task. Instead, using integrators to “sum up” signals is a way to figure out where you might be in a process. Discretizing a signal and then counting how many times it happens can have many uses in control systems, measurement systems and a range of other applications.
  3. Memory — Storing analog signals would be difficult. For even a simple 0-1V signal, you would have to be able to store an infinite number of values. If you have 4 bits to represent the range from 0 to 1 volt, then you instead only need 16 places to store values. In control systems and other places that require memory, the old way to “store” values was to sufficiently delay them and feed them back so as to combine them with a newer signal. Using memory now allows for interesting systems and use of state machines to determine what to calculate or execute next based on current and past input data.
  4. High noise environments — If you are trying to transmit an analog walkie-talkie signal (5Vpp sine wave) in a field that happens to have a white noise generator transmitting (2V) at the same frequency you are using, it is likely that whoever is on the receiving end of that signal will also get a good bit of white noise in their signal (think static). If you instead use a digital signal (varying between 0 and 5V) your friend who has a digital transceiver will be able to discern your transmitted highs (5V) and lows (0V) even if they also have noise added to them. Once the digital data is received and decoded, the original signal (5Vpp sine wave) can be reconstructed on the receiving end.
  5. Signals Transmission – As stated above, there are advantages to transmitting digital signals as opposed to analog. Most notable is the lower power spectral density of the digital signals and that less power is needed to transmit those signals. In current events, we see TV transmission changing from analog to digitla because of the lower power required to transmit the signal and the possibility for multiplexing signals on specific frequencies in order to get more channels transmitted in the allowable spectrum.
  6. Data storage — To use the mp3 example again from above, data is best stored in a digital format (easy there audiophiles, records are alright for some people too). True, some information is lost, but only information above the Nyquist Sampling rate. In audio signals, most people cannot hear above 20 kHz, so there isn’t too much to worry about beyond that (perhaps the harmonics that some people claim to hear and desire in their recorded works).
  7. RF — Digital Signal Processing (or DSP) is one of my favorite digital topics. There are so many cool things you can do with a Radio Frequency (RF) signal once it is sampled and put into a powerful processor. In fact, this process makes your cell phones and Wi-Fi connections possible. FIR filters, CIC filters, baseband shifting and so many other interesting topics make it possible. Hell, maybe some day I’ll start “Chris Gammell’s DSP Life“. Anyway, can’t we do this stuff in analog? Well yes, we can. But with RF, it comes down to precision. With the filters listed above, you can trade off processor time/power for a more precise filter. In analog systems, you instead need more and more precise components and increasingly complex systems to achieve similar results. In DSP there is also reconfigurability, either through logic rework (FPGAs) or coding (in DSP chips), so long term investment usually will favor DSP over analog RF solutions. Finally, there is more efficient use of bandwidth with digital systems, so you can shove more data into the same frequency space. All of these things have helped to push the RF areas towards digital processing.

I think one of the most interesting things when reviewing this list is that it’s possible to implement solutions in myriad ways. Oftentimes cost and tradition (or past work) determine which way a solution will eventually lean (digital or analog). And although I hope to expand upon it in future posts the most interesting thing to me is that analog and digital begin to merge at the extremes: do analog signals really exist if energy is explainable by quantum mechanics? Will digital signal continue to only have two logical states when there is so much data storage capacity available between 0 and 1?

Please comment on the above lists–right or wrong–and let me know a situation or two that you think benefits from analog or digital.