A philosophy of biomedical instrumentation and design

A final lecture delivered to the students of BIOMEDE 458, Winter 2018

For as long as I can hope to teach at fine universities such as the great one that employs me, I will endeavor to have some deep and profound thoughts on the practice of my craft here. To that end (and for many others), at the conclusion of each class I teach, I put together a few words outlining what it is I think we have done here and why I think it is important. What follows is still an experimental way of reporting this information: a rather long rant-style essay on the importance of our subject matter, with an accompaniment via slideshow. All those who may subject themselves to listening to aforementioned “rant” should do so knowing that at any time and for any reason, they should feel as free as possible to tune out, leave, or otherwise disengage yourself from my rambling. Indeed, there will be rambling.

There will also, I hope, be a nugget of truth to all of this. That nugget of truth is sometimes hard to express, especially when the moment necessary for its expression, such as a quiet room with rapt attention and no other business to attend to, does not come about as often as one might like. This is yet another reason why I like to carve out time and space for these “philosophies” at the ends of my classes. It’s the last, and sometimes only, chance I get yap at you about all the stuff I think matters from this subject matter that I haven’t gotten a chance to say to you given the current confines of the class.

To whit, what I think matters that you get from this class is an ability to understand and design systems for the acquisition and transmission of biological and physiological information.

Indeed, I once described such biomedical instruments as “systems that convert a biomedical signal in some useful way.”

Through this class we have seen that there are lots of medical devices.

Even though even we only explored, really, about three or four.

We learned about basic physiological systems.

We learned how to convolve those system with our systems to thereby interpret the signals that results.

The math was sometimes tough.

But it led to some useful shortcuts.

We learned the basics of acquisitions.

And the fundamentals of signals.

We also got to experience, sometimes much to our chagrin first hand, some practical limitations to the art of biomedical instrumentation.

With any luck, by this time, you have a good deal of respect for filters.

And op-amps.

And the rules governing the behavior of op-amps

And the types of amplifying those little operational amplifiers can do, such as:

An inverting amplifier;

A non-inverting amplifier;

A summing amplifier; and

A differential amplifier.

Sure there’s a few other useful ones, but if you’ve got that much, you’ve got a lot.

We taught you, I hope, at least three types of passband filters. The first is a low-pass that gets rid of high frequency, generally static-y, noise.

The second is a high-pass type that we typically use to get rid of of electronic drifts or some of our slower more rumbling biological signals (such as the gut’s dipole or the effects of the eyes in EEG).

And the third type is their combination: the bandpass system with a middle passband flanked on either side by two stop bands.

We are by now duly familiar with LabVIEW, some of its quirks, and its general limits of practice.

We got to learn of the class’s quirks including its gender composition, smile-having pictures, and optical assistance needs.

And we got to learn a little bit of the class’s quirky instructors.

Those instructors tried to teach the class as best they could. Charting the whole thing out.

Giving you time to become acquainted with the material.

Giving you an opportunity to demonstrate actual-world applicability of the material.

Giving you a chance to make whatever you (and your team) want to make.

And, like I said, at times we tried to throw a little bit extra in there for you.

All the same I wanted the class to be on the whole, predictable.

I wanted you to know to try, hard.

I wanted you to make of each day more than the last.

I wanted you to convince yourselves why you wanted to be here.

I also wanted to point out that our work actually, quite literally, matters to the lives of millions of people globally. The same cannot be said of most other professions.

In between, I taught a little bit of the class, including the section on electrocardiography.

In said lecture, I had simple messages,

Vivid presentations of mathematics,

And employed class leading pedagogical approaches to color cues for viewers of the presentation.

I also hope to have shown you a little bit behind the current of this whole enterprise by telling a little bit of our rarely spoken aloud history. Specifically in this case, the short vignette on Jimmy the Dog.

In case you forgot, a fellow by the name of Augustus D. Waller was an early pioneer in the field of electrocardiography and provided the first published presentation of the heart’s dipole as a vector. And he did so with the aid of his dog Jimmy.

His simple experiments with him make his dog stand in bowls of salt water still influence the way we do our science today. The same might be true of the great electrooculographic race of 2018 that’s been brewing in this class.

At times I wanted to convey the very complex in an almost ridiculously stripped down way.

I think it allows us to put concepts more starkly at times.

Information can be relayed in a temporal order so that it hits your brains just right. After all, I want you to know all this stuff.

We learn how the vector of our hearts is made.

And how it moves.

We showed its pattern of motion.

And traced out its path.

At times I think I may have scared you all. Either because of the complexity of a

Its genuine risk, or

The division of labor.

Still, in the end, I think you were, each of you, capable of performing just about all the shared tasks and responsibilities we asked of you in this class. And that’s something great.

Though not the most highly attended events in the world, I was grateful for the opportunity to explore new experimental modes of teach as embodied by my three lecture series, “Quantifying the self.”

Those of you that didn’t attend, here’s a short summary. The names come from literary works with a relevance to medical and biomedical situations. In the inaugural case, the opening lines of Karl Ove Knausgaard’s My Struggle describe the role of ones heart in both life and death. Such a hyperlocating of the biological into the everyday and the important speaks to me and what it was I was trying to accomplish with these three courses.

In this series we asked deeper questions, such as the concept of normalcy in biomedicine.

We looked at the fundamental composition of physiological signals.

We looked at typical values so that we can know how to design for such systems in the future.

We glanced at very complicated material in intuitive ways.

And from multiple perspectives

We boiled things down to their essentials.

And their consequences.

We saw how we could think through different types of noise and error within our signals

We saw how our “every day” medical devices worked in both the clinic

And in the consumer spheres, as is the case for photoplethysmography.

We spent a section exploring the electrical components of the human body

Starting with Galvani

And ending with Hodgkin-Huxley.

We looked at various manifestations of electrophysiology including




And electrogastrography.

We even touched on (and speculated about) many other types of electrical phenomenon we could possibly capture with our instruments.

In the final lecture of the series, a small cohort of us worked through possible topics to be included in a wearables class to be offered here at the University of Michigan.

The title came from one of my favorite author, Will Durant, a book of whose I have with me up here today. To be discussed later.

I presented the general sequence and range of topics.

I went through a wide range of biosignals that currently have market ready products, explaining how they are captured, who captures them, and why.

We discussed all the places you could put wearable devices.

We discussed the future of the field.

We discussed current limitations.

I recommended the use of a small microcontroller platform for the hardware

And a commitment to open-access for the software.

All and all, I did what I could with what I had.

And I hope it amounted to something. At the very least, to me it amounted to a great deal personally. I got to teach one of my favorite subjects in one of my favorite classes in one of places in the world. And to do so for more money than I can spend and more adulation than I can handle. For me, this has been a great experience. That is due in no small part to your contribution. And if you do not mind it and do not have anywhere to be for about the next twenty minutes or so, I’d like to spend some time thank each of you and commending you on your contributions.

I have listed you all in order from the date of your enrollment, with your numbering coming after my first batch of students from ENGR 100. You were the second class I ever taught and again, I cannot emphasize how influential you all will have undoubtedly been on me as I continue through this institution and through life.

With that. The list.

73. Seventy-three. T. I wish we had gotten to know one another a bit better during the tenure of this class. And that’s roughly true of most in this room I suspect, I really wish I could have gotten to know you all better and please don’t you all be timid about sharing your achievements in life with me. How else am I supposed to take credit? T. I wish we had gotten to know one another a bit better during our time here. I saw you at B. W. (soon to be Dr. B. W., Ph.D) defense and saw that you even got a shout out for his work. The quality of his work speaks to the quality of yours and that’s something I wish I knew more about. All the same, I wish you luck in whatever line of work you do well.

74. Seventy-four. C. I recognize that this is not the parting goodbye that it will likely be for some large subset of this class, as I’ll likely be seeing you at the next XXX. That said, you seem to be riding the line pretty well between biomedical engineering and engineering education. While I will continue to personal try to tip those scales toward the engineering side of things, I have no doubt you will go on through a successful doctorate and help us figure out how to do this act up here better.

75. Seventy-five. C. The beginning of your presentation may have been one of the purest forms of poetry this class has produced. Quote: “So, we are the L. C. B., as you can see. I’m C.” Followed by “I’m C.” – “I’m E.” – “V.” – which has quite a lovely lilt to it. Thank you for making possibly a brief lovely moment in this otherwise dreary world.

76. Seventy-six. N. This might be the single weirdest compliment you get all year. But harken back, if you will, to our first homework when I asked, as the final question, the following: “Find some values of the magnitude and frequencies of the following biological parameters/measuring techniques before they are modified by a system. Be sure to cite your sources and explain why you trust them.” From a purely utilitarian standpoint your answer ranked among the (if not the) best. If your boss asked for what I asked for, they’d be quite satisfied at the quality of your work. That can be said of few in this world. Rank yourself among their number.

77. Seventy-seven. K. J. I believe it was you who noted that it was your team, H. M., that “have the Lamborghini” when prompted about a race with another team’s remote controlled car. I hope such works are backed up by hard work and genuine striving. I suspect that much will get you far. And that much and a Lamborghini will get you farther.

78. Seventy-eight. K. K. I suspect you’ve learned as much as any in this class about our current system of healthcare this semester. I hope it hasn’t put you off the subject too much. And if I remember correctly you’re supposed to be heading to J. this summer for an internship? May such a trip and indeed all such trips you may take in life be both safe and fulfilling for you.

79. Seventy-nine. B. You have consistently turned in good homework, produced good lab work, and demonstrated a willingness to help your team with just about all possible matters in the lab. You have been a good student of the class and I hope some of what you’ve learned here serves you well in the future.

80. Eighty. I. Your answer for the question in Homework II about the ECG vector was inspired. It was a really nice way, without being too messy (but without also being too neat) of showing how the measured dipole will change along each lead. If this is the kind of work you produce on the back of an envelope, I suspect that the skills you employ in a professional capacity will be much sought after.

81. Eighty-one. M. M. P. You did quite well in presenting the why your team’s project, E. It’s a generally underdiscussed ability, but setting the necessary foundations for the presentation that follows is a skill and one you seem to possess. Good job on the last presentation and good luck on your next.

82. Eighty-two. V. There’s something that tickles me pink about a University level project which you once described thusly: “We don’t need a great deal of materials outside of lab other than an RC car.” It is precisely sentiments like these that I know generally get little budding elementary/junior high/high school engineers stoked on entering a program like ours. I imagine if you told a younger version of yourself that not only yesterday you were but tomorrow you will be working on an electrooculographically remote controlled vehicle, you’d be pretty proud. You should be. As should the rest of you.

83. Eighty-three. E. You had the single best looking homework I’ve received from a student all year. I’ve decided, as such, to create an award (of no monetary value) to celebrate such an achievement and to bestow it upon you. The Best Homework of the Year Award, 2018. Your tasteful use of typeface and its font paired well with utilitarian whitespace. It is downright beautiful. Thank you for the art.

84. Eight-four. S. Thank you for attending each of the Quantifying the Self lectures. It really means a lot to me – a first year teacher of all this – to see that there is at least one student out there, at least one, for whom this subject matter is of possible interest and worthwhileness. That, when it comes right down to it, is why a person like me signs up for a job like this. And so in a very real sense, thanks for making that little experiment worth it.

85. Eighty-five. M. P. Perhaps you knew I was a sucker for the big font, but the stark simplicity of your presentation style is fine by me. Sometimes in institutions like this we encourage you all to say too much on a topic. Short and to the point works. I hope it continues to work for you.

86. Eighty-six. R. I feel like you are quite the onion once someone sits you down and talk to you for a bit. At first I thought you were a mostly-maybe-kinda-beyond-this-class type of EECS student, but with time I found both your personal history, such as your time in Germany and China, and your perspectives on history – such as on why languages might get the way they do with time, rhyme, and borders – indicative of a modern day cosmopolitan. To have you counted among our biomedical engineering ranks, even if but tangentially, has been quite an honor. I hope you go on to see even more of this world.

87. Eighty-seven. T. If I recall correctly your favorite show is Black Mirror and as of January of this year you had not watched the latest season. I even joked to make it part of your homework. Have you watched it? [Joke about making him put a slideo on his final presentation to tell me what he thought of the first episode.]

88. Eighty-eight. S. Perhaps you can’t appreciate it now – I’d wager you don’t yet have sufficient distance – but your decision to take up sailing last summer was metaphorically relevant to all of this, to this whole college thing. What is it we’re trying to do here? Who are we trying to become? Where do we want to go? Having literally sailed the seas (or at least a lake probably), has to have prepared you for what’s to come. May you meet it with temerity.

89. Eighty-nine. J. Hailing as you do from C. this year had to be one of the most confusing sports times in recent memory for you. To cap the whole thing off for you and for all of us with a second place finish to an unfortunately and obviously better team. But you know what, I’ve been proudest when my team’s won second place. I like when those who through persistence rise to the challenge, rise through the ranks, rise up to top. Let us recall T. R.’s word on the matter: “It is not the critic who counts; not the man who points out how the strong man stumbles, or where the doer of deeds could have done them better. The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood; who strives valiantly; who errs, who comes short again and again, because these is no effort without error and shortcoming; but who does actually strive to do the deeds; who knows great enthusiasms, the great devotions; who spends himself in a worthy cause; who at the best knows in the end the triumph of high achievement, and who at the worst, if he fails, at least fails while daring greatly, so that his place shall never be with those cold and timid souls who neither know victory nor defeat.” May you, at times, dare so great.

90. Ninety. A. A. A Bo Schembechler reference in this University will always get you far on this campus. The team is important, the team is the unit of operation, the team drives what we’re trying to do here forward. May each of you recognize in this some bit of truth. Consider but only how much of your opinion of this class has been shaped by the same hearty band of biomedical engineers for the past few months. Those closest to you – the team – has made you who you are and in turn you have made of it what you will. In the best teams, the best of us are brought out. All this to say, keep making those Bo references and you should do just fine.

91. Ninety-one. S. You once said of your project, “Okay, so obviously the big step of this is to get an EEG that actually works.” Such concise nutshelling of situations is a valuable skill to have and to hone. May you keep your wits sharp and about you.

92. Ninety-two. E. S. We saw through our alphabetical investigations of our class composition that your name comprises the class’s average initials. I should say that even were it true that you were but an average student in this class (and nothing could be further from the truth), that among this group, that’s pretty darn good. We’ve got future doctors and inventors and clinical engineers and techs and managers and sales and maybe an eventual accountant or two among us. All this to say, you and everyone around you make up an extraordinary group of individuals. And I hope we all appreciate that from time to time.

93. Ninety-three. C. I feel lucky that I got to get to know you a little bit better at that industry-alumni-university event thing. It’s great when the bounds of the classroom environment (which are often weirdly restrictive, even as in this quasi-rant, listicle format). And but so eating dinner with you and just shooting the breeze for an hour or two was great. If you’re ever at another one of those, come by my table.

94. Ninety-four. P. Thank you for attending the optional lectures. I really did think more students would be interested, but as both you and I and really most everyone in this room knows, not too many people went. Still, you checked out (along with S.) and I hope it was to your benefit. I know it was to mine and having you there to help me was and continues to be appreciated. You appear to have a deep and abiding interest in medical technology and I hope along your trajectory through life you get to engage in some wicked cool things.

95. Ninety-five. B. I know you will go far in life. To begin your presentation or rather to let a rowdier portion of the audience know that their time of rowdiness was coming to an end you did a hand gesture whose power images fail to properly demonstrate the magnitude of. I mean, it looks like you actually blew S. back with it. You commanded an audience of some lofty peers in this class and I hope you continue to do so elsewhere.

96. Ninety-six. J. Your 3D printed ear subplot in my life really added to some of my favorite days in recent memory. Days where I’m scrambling to make sure a dozen things are all happening at once and I walk in one Tuesday or Thursday morning and you’ve got what at least in my retelling’s estimation is like half a dozen variously sized 3D printed ears with one of them being particularly large and I think to myself, this is the future towards which it’s all been heading. All this striving and effort, technology and progress, all this advancement to where we can form the very world at our command (albeit in a still limited sense), and it’s led to our being able to make ears of any size in any number at our command. Such is the power of a biomedical engineer. May you wield such power responsibly in all your days to come.

97. Ninety-seven. R. People speak well of your abilities in BMES. Indeed, I believe it was through the demonstration of said abilities – namely some social event with the Department – that we first met. You appear to be an active, participatory, and well-liked student in this community and you’ve done well in this class. That’s pretty remarkable and so I prepared the aforestated remarks. Do well enough in life to do some good.

98. Ninety-eight. A. It perhaps comes as no surprise to you, your team members, or those that have gotten to know you through the course that you were an influential presence on your team. It was obvious that you cared deeply about what it was you were all trying to do and took great pains to try and do it well. I respect that kind of gumption. May you keep at it.

99. Ninety-nine. M. Ninety-nine is one of my favorite numbers. By happenstance you have shaped up to be one of my favorite students (though, in fairness, and in a bid to win back the majority’s affection, you are all one of my favorite students. The work you do on behalf of M-HEAL and within our lab section are both earnest and well done. So far as I can tell. And though you may only wear one contact lens, you seem to able to keep both eyes on the ball. If this class but built up your courage to swing, I will have considered it a success.

100. One-hundred. L. May you appreciate that now part of your life’s trajectory was the straight-faced suggestion for a biomedical engineering project that someone (probably S.) yell in your face while wearing an essentially homebrewed electroenecephalograph to detect “some kind of response.” I’m not quite sure what you’re measuring, but I’m glad you’re looking to measure it. May you measure it and up all through life.

101. One-hundred one. A. I’ve meant to respond to an email of yours for awhile. I must apologize. I am, and fear I am likely to remain, not that great/jazzed/all about communication via email. So if any of you plan on emailing me after this class, which I encourage, advocate, and borderline admonish you to do, know that it might take me a few days to respond to your email. Mostly, as I hope you’ll appreciate, it’s that when I go to write something down, I’m trying to convey something. The conveyance of that something, such as my current respect for you as students and my personal hope for your future successes, is often not possible in an email, whose bounds are so narrowly confined within pieces of glass like this and that. Consider the following, when you are “communicating” with me via the this here electronic mail, I have to read either through this piece of glass or this piece of glass, and then I’ve got to transmit my thoughts on whatever matters I’ve got them on at that moment. As if human beings over eons developed complex syntactical arrangements, context specific tonal shifts, and literal facial expressions to prepare ourselves for a future in which our primary mode of talking to another human being is through some electronic middleman circumscribed, as previously mentioned, by finite, confining glass. Furthermore, I am sorry to have made this little bit I wrote about you to be mostly about me and my daily struggles with communication. This marks the second time email has failed to convey my current respect for you as a student and my personal hope in your future success. First as communication, second as metaphor. This is a larger statement on what it is I’m trying to do here. May you make larger statements than these in your future work.

102. One-hundred two. A. If I recall correctly, you play the bass. I play the guitar. Not well, but “well with others.” So should you find yourself wanting to play a walking bass line to the rather flimsy gypsy jazz I can muster, send me an email.

103. One-hundred three. B. I hope you enjoy Fitbit this summer and soak in a part of the world I myself was personally steeped in for about two years of my life. Right around that area. Literally blocks away. Exercises like these give one time for reflection and those years of my life were formative. I suspect they will form some integral part of your life. And I’m excited to see what you make of it.

You are, each of you, worthy peers. You are among the most capable engineers in the world. I hope you take a solace in that from time to time.

Allow me to end with a parting thought. There is a metaphysics to engineering that goes unspoken. One must develop the sense, as an engineer, that the fuzziness of real life can be approximated usefully. Unlike some of our brothers and sisters in the STEM quadrivium (the mathematicians, the scientists), our reality need not be precise nor very accurate at times, so long as it sets out to accomplish what it was designed to accomplish. Our shapes come with tolerances, our rigor with fudge factors. We see the world not how it is but about how it is. Give or take, plus or minus, within such and such a percent. While some of said brothers and sisters can hold in their minds exotic manifolds of multidimensional spaces and still others that can conceive of an elemental particle conflating matter with waves carrying a single discrete unit of energy at the fastest speed possible in the universe (or just about), we just need to know how the LED is going to look when the user is holding it at some angle away from them. We are a practical lot. Not beholden to the right the answer, but a right answer, engineers – of which I hope you will all one day count yourselves among – may content themselves with three simple things: a solution, a test, and a better solution.

Seeing as you have now taken this course, studied this subject matter, and waded out into our field of biomedical instrumentation and design, I encourage you to think on how you would do it better. What more needs to be done, what needs to be done differently, what needs to be emphasized, diminished, scrutinized? Among the last thoughts Will Durant relays in this book is the notion that our vitality depends on the tension between the new and the old, “whereby innovation meets tradition, and the ardor of experiment fuses with the coolness of experiences.” I hope, we have, with this class, optimizing your ardor and coolness.

With that, I thank you for the opportunity to dismiss this class on final formal time (as the next time we all meet together will be for the presentation of your project). I hope you all do well on your fast approaching design projects and your ever-to-the-horizon journeys. I’ve done what I can for you here and I trust that you can do more. Good luck.