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It's been a while since I first wrote about how useful computer vision can be in product development, and I recently put together a quick demo for other engineers at my new gig (@ Continuum) that is cleaner and more thorough than previous versions (plus it uses the cv2 library instead of the deprecated cv […]

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A few years ago I architected the database for Aircast's new line of orthopedic walking braces. Was digging through my old notes and saw the video that Derek Hugger had put together showcasing the flexibility of the database.

Anyone have any thoughts? We are at a junction where we have to make a decision. I am quite interested in any experiences any of you may have with either system.

Much of my content here is search engine bait, but this one goes out directly to my wonderful subscribers and commenters. As you may have noticed, I have not updated this post in a while. Those of you who have been subscribing to blogs for a while might be thinking "great, another abandoned blog". Not […]

I recently joined quanttus, a really exciting new startup based at the CIC in Cambridge. We're growing really fast (I was the first hire in the ME deparment) and are looking to hire, among other things, another senior mechanical engineer. So read the description below and, if it feels up your alley, apply here Position […]

One of the more controversial posts I've written was about how unigraphics sucks. I wrote it a few years ago and have occasionally fielded comments from people with strong opinions. In responding to one earlier today I looked at the updated chart for the first time in a while and couldn't help but notice the […]

Every project is different, but principles tend to repeat themselves. When faced with a problem that doesn't have an immediate solution, I find it worthwhile to get a few smart people in a room, get them fed, and think about the problem. That's where the hard part comes in: just how should we think about the […]

Program management, to me, isn't fun. I don't like to think about it. I would much rather design a mechanism, run a simulation, build a robot, create a visualization, or perform some data analysis. The thing is, all the cool things I like to do take place in an environment (the program) that is completely defined by how […]

A Fast Fourier Transform can take nosiy data that look like this: And give you something much more precise and useful (ie the freuqnecy, amplitude, and phase offset), like this: Usually you see these used for digital signal analysis, but I've found it to be really helpful when analyzing sinusoidal data coming from prototype mechanical systems. […]

In times of change learners inherit the earth; while the learned find themselves beautifully equipped to deal with a world that no longer exists. First, the doom-and-gloom: I think we are at the beginning of an era of great change in the mechanical engineering discipline in general, and product design in particular. A grand statement, […]

I've recently had occasion to look at various methods for measuring fluid flowing through a tube. In my research I came across a really great set of videos from Endress Hauser that describe different methods for doing exactly that. An interesting distinction that I was previously unaware of is that some methods (e.g.  the venturi […]

A while back I shared a video where Rob Wood of Harvard discussed the challenges inherent in flight at the scale of 100mg. Well they were recently successful. Check out the video.

For a while now I've been recommending 507 Mechanical Movements as a good reference for brainstorming mechanisms. Well, maybe it's about to get better thanks to Matt Keveney at He is setting out to animate all 507 mechanisms and make them freely available. This is no small undertaking. I attempted it myself and got to ~10 […]

I'm fond of telling students that the most important skill they are developing is the ability to learn. In that vein I just had to share this graph from Seb Paquet:

My posts have been less frequent in the past few months, and I want to ensure to you that it isn't because I've got nothing to talk about. Quite the opposite, there is so much going on that it is difficult to carve out time to sit down and write an article. I hope to […]

A few months ago my team and I wrapped up a pretty big project. It was big in terms of effort, annual volumes, as well as the size of the parts themselves (injection molded parts well above 1 pound). It was a really cool project. Unfortunately I can't tell you anything about it (yet... they […]

....just to name a few gripes.

I've been doing a lot of robotics lately. Mostly looking at platforms for a demo (Raspberry Pi vs Arduino vs Beagleboard) as well as libraries (ROS) for controlling the robot. Also the cost/benefit of controlling via MATLAB, LabView, or Python. In the course of that grunt work (which I will be writing about...first I've get […]

“Things may come to those who wait...but only the things left by those who hustle.” -Abraham Lincoln

Art Rousmaniere, a man that doesn't write very often and whom I hold in very high regard, has written an article over at Farm distilling the connections he's made between a decade of coaching FIRST robotics teams and multiple decades in product development. It's a great article, you should go read it.

I've talked a lot about tolerance analysis on this site, but I haven't talked too much about GD&T. I suspect a few of you don't know what GD&T is (Geometric Dimensioning & Tolerancing), most of you have probably used it a little bit, and a sliver of you are gurus. Don Day is a guru, […]

I recently mentioned that MIT was now offering their 600 course, Introduction to Computer Science and Programming, online via edx. Well I've signed up. It starts monday and I'm excited. More importantly, you should be excited. You should be excited because programming is a skill you need, and it's never been offered for free in […]

My life tends to skew towards what one might call 'minimalist'. I exemplify this in my life and I attempt, as much as possible, to implement it in my designs. I encourage you to spend a few minutes with this video. If you're feeling this video, you might also appreciate new vs perfect.

This has the potential to be the least-polished post I've ever put up here (long-time readers will know that means something). Why is this so? I'm giving a presentation tomorrow on a topic I know very well, but have never presented on before. It's a topic that is certainly relevant to mechanical engineers (and thus […]

Followers of the blog know that I've been playing around with python and computer vision. Well I recently wrote an article describing how computer vision can be used in product development. In the video below I go through the steps necessary to extract data from someone walking during the heel-strike to toe-off portion of the […]

From Proffessor Eric Grimson at MIT ...what we try and do is, we take a new problem and map it onto an old problem so that we can use an old solution.In order to be able to do that, it's nice to have in our heads an inventory of previously solved problems to which we […]

I recently had occasion to look into lockable gas springs (like the ones you might find in an office chair). I already had a pretty good idea how they worked, but I've never seen it illustrated as clearly as it is over Bansbach. They also have a lever-, cable- (you may not have heard of […]

A while back I mentioned that MIT had done something innovative: they offered a course (6.002x – Circuits and Electronics) online that, upon attaining a passing grade, would result in an actual credential. Well they’ve since expanded and recruited Harvard and Berkeley to the effort, and the result is edX. In particular I’d like to […]

I just came across this video via reddit. It does the best job I've seen of explaining a differential. It starts with a pair of motorcycles explaining how wheels turning on a larger radius need to turn faster than the wheels on a smaller radius in order to keep the same angular position, and progress […]

For a few years I was a part of our co-op recruiting and hiring process. I've since stepped back and let some others have a go at it, but the lessons I've learned remain. Lee Panecki, one of our several success stories (success being defined as a co-op that we ended up hiring full-time) has […]

I'm sure I'm not the only one who has been geeking out about Curiousity... here's something to play with: via The Atlantic Curiosity rover: Martian solar day 2 in New Mexico

If you've ever advocated (i.e. solicited funds) for more prototypes, you know it can be a tough sell; how do you articulate the value of frequent  prototyping during the development process? I find it useful to consider an illustrative (if simplified) anecdote. Imagine an engineer, Fred, who needs to develop a mechanism(lets say for automatic […]

Cleaning out my desk area yesterday I threw away a bunch of vendor pamphlets. The only ones I kept (the vendors reading this should take note) were the ones that had a useful guide to their respective technology; not the ones that talk about how they are a family business that has been dedicated to […]

Not too long ago I mentioned I was playing around with opencv and python. Well, in between client work I've moved a bit forward. Now I'm calculating the angle of a line between two tracked points relative to the horizontal. It's a relatively straightforward thing to implement (although my code, below, isn't exactly pristine), and […]

Projects always take longer than you expect, even when you account for the fact that projects always take longer than you expect. a.k.a. Hofstadter's Law

I have been playing around with Python quite a bit lately and have recently been playing around with OpenCV (Open Computer Vision) to see what if I couldn't get it to track something. Well I did (that something being my son's toy bear), and it was surprisingly straightforward (and free!... take that MATLAB) Anyway, I'm […]

Bayesian statistics are widely used in fields like robotics and machine learning. I've been playing around with the theories over the past few months (sorry for the lack of posts by the way), and recently came across something with a high (worth sharing)/(time to write a post) ratio. It's called the cookie problem: Suppose there […]

Pulse Width Modulation is a workhorse in  electronics. Essentially, PWM is a fancy way of saying: turning the power on and off really fast such that it looks like you have a constant stream of a lower amount of power. A common use of PWM is for the control of motors. Especially in the case […]

via reddit. skip to 2:20 to see the robot. THE MARMALADE Identity from schoenheitsfarm production on Vimeo.

I recently had occasion to compare various types of actuators. As I was going through the traditional technologies (pneumatic, hydraulic, electric), I came across a quite amazing site: What's awesome about it? This table pretty much sums it up, but be sure to check out the site to see the rest. Muscle is a linear […]

consider the following: I burn ~70 calories per hour while sleeping. Science tells me that's 81 Watts. That's about what my old CRT monitor used. The body makes electronics look downright ineffeccient.

Physical prototypes are expensive, but not making them is even more so. The next time you are trying to decide whether or not a prototype is worth the money, consider these two things: your design team is never more productive than the few days after receiving a prototype prototypes force stakeholders into consensus; it insists […]

Joichi Ito, director of the MIT Media Lab, prompted by Steelcase: One hundred years from now, the role of science and technology will be about becoming part of nature rather than trying to control it. So much of science and technology has been about pursuing efficiency, scale and “exponential growth” at the expense of our […]

I spent the day today down in Waltham at the ANSYS confidence by design workshop. I'll write in depth about some of the topics later, but for now I'll just leave my notes right here. submodeling A coarse mesh will give accurate displacements, but not stresses. This is a reflection of the fact that the […]

While I'm waiting for ~15,000 features to regenerate, I find myself wondering what size databases you all work with.   ?

A while back I wrote about urethane castings. In the article I said the following regarding prototyping: Urethane castings are your only choice for elastomer prototypes of any decent quality. Period. I caught a little bit of flack for that. Specifically, a few people were keen on mentioning Objet's Tango materials. I'm not particularly keen […]

long time readers will know that I'm a big fan of The Economist. Well, they continue to earn my subscription dollars. Over the weekend I read their 14-page report on what they are calling the third industrial revolution. Simplified, their premise is this: As manufacturing becomes more and digitized, disruptive opportunities will be created. I […]

Looks like amazon is trying to compete with McMaster Carr. At least that's what it looks like when you first land on At the moment it's no competition: Amazon Supply doesn't even have CAD models. Still, with amazon's logistical know-how it's not hard to imagine them dethroning McMaster as the hardware supplier of choice.

By definition, the people performing FEA studies know more about it than most (if not all) of the people reviewing the final report. This can become a problem if, among the rainbow colored plots and animations, a less savvy reviewer finds themselves believing that the simulation is a reflection, instead of an approximation, of reality. […]