UptownMaker

In mathematics, a degenerate form is one that cannot be perturbed in some way without being rendered a member of a larger, more complex class.  For example, a circle is a degenerate ellipse- change the constant multiplier of one of the terms and you push the form out of the class of circles into the larger class of ellipses. Next time you're solving a problem, ask yourself: am I solving for a degenerate form?  And, if the answer is yes, is that important?  Let me give an example where the answer to both questions was "yes".  I was tasked once with supporting some motion code which was intended to align a circuit board on a conveyor belt under a camera. The code as written worked fine in the lab, but in the field, customers began to complain of erratic and unpredictable behavior- boards which would be incorrectly positioned at the start of inspection, pushed off the end of the conveyor, etc.  It turns out that the code had originally been written to the dege...

Whenever you put a project out there in the community, be it on your blog, a community board, or as an article in another venue (or if it gets picked up by say, Hackaday or Make), you're bound to get some comments that are, shall we say, worth less than the calories they took to type.  Worse still are the times you get these comments from someone to whom you are explaining (in meatspace) your current pet project- those times can be a SERIOUS buzz kill and I've lost the will to finish a couple of projects after comments like this. "You know, Target sells something that [does that]/[does almost exactly that]."  This is more common in meatspace than on the web, I think, because the web audience self-selects for people who understand that the joy is in the making, not the having.  And, frequently, the "almost" is where the bugaboo lies- I want EXACTLY that, not ALMOST exactly that. "Arduino is for losers."  Or some variation thereon.  Arduino, as a p...

... as proposed by Jeri Ellsworth:  the "Jones", after EEVblog's Dave Jones. As with all SI units, we must define it in terms of base units, so I propose this: 1 Jones = (# of complaints about a topic) * (sum of levels of annoyance caused by said complaints weighted by exposure frequency to causative events, in seconds between exposures) * (# of people likely to be exposed to your ranting) Obviously, the level of annoyance varies from person to person; I imagine a level 1 annoyance ("mild eye rolling followed by repetition of action until desired result is achieved") for a more patient colleague might be a level 5 annoyance to me ("loud sigh with posture change and muttered profanity") and could rank to a level 100 for someone else ("widely distributed internet video rant with attendant behavioral change and increased probability of property damage to exact retribution on an inanimate object"). As a practical example I'll float m...

On the heels of a few tweets regarding linear voltage regulators that I passed with a friend yesterday, I think I'll do a couple of posts on voltage regulation. First, the general concept: voltage regulation is the creation of a stable, low-impedance DC voltage source from an unregulated DC voltage source.  Examples of unregulated DC voltage sources are batteries, "wall wart" type AC/DC converters (even though many of these create very good voltages (these days, anyway), you should always assume that you (or someone else) will plug a different supply in), car cigarette lighter sockets, rectified and filtered transformer outputs, solar panels, fuel cells, dynamos, and fruit with pieces of zinc and copper in.  In fact, pretty much anything other than a locally generated voltage from a well-designed regulator circuit should be treated as an unregulated source (for design purposes, at least). This first post will concentrate on linear voltage regulators.  Sometimes you...

A common problem in electrical engineering is the use of a resistor divider to create a circuit which derives a second (lower) voltage from a known voltage.  This can be for a reference voltage to an ADC (as on the Arduino) , to set the voltage on an adjustable regulator (where the regulator seeks to maintain an output voltage adequate to produce a set voltage at a feedback node), or to calculate the gain on an amplifier circuit, among other possibilities. The canonical voltage divider circuit Usually, we know Vin and Vout, but R1 and R2 are unknowns.  We usually pick one of them (based on what's on hand, in the parts library, time of day, dog's birthday, roll of a 20-sided die, etc), then calculate the other.  Almost always, that results in a value which is not readily available, so we pick the closest value, calculate the error, decide it's too much, and pick another resistor value and start over. Error in the output voltage has a number of possible sources:...

Somehow I've become a prolific blogger lately.  I wonder if this will last... Today at work I had a serendipitous moment of seeing two desktop objects in an abnormal light: a small, scavenged lens cell and a super cheap (2 for $5) LED flashlight. As part of my on-going inculcation into the mystical arts of optical engineering, one of my fellow engineers demonstrated to me the ease with which an illuminated object can be projected onto a surface, if the various distances are correct.  His demonstration was with the image of the lit window that faces our cubes, but it occurred to me today that, by tweaking distances, I could probably get a similar image from my LED flashlight, writ large on a blank whiteboard. Tah-dah!  What's more, I found that, by moving the lens slightly along the optical path, I could bring different elements of the LEDs into focus.  But lets start by analyzing this image. First, you can see (though not very well) that the LED lenses are f...

Once you've got it all together, where do you use it? My workspace is divided in half- an electronics bench with tools and a PC station.  The PC desk is boring- two 19" monitors, speakers, printer, etc- I won't bore you with pics of that. There are only a couple of things I really want to mention here as being special about my desk.  First, the knife holders.  These are the standard type of wall-mount magnetic knife mounts.  Mounted vertically (because they were too long for horizontal) they hold my small tools- little screwdrivers, a wire stripper, a side cutter.  I have duplicates of all of these tools in the mobile kit but it's nice to have them handy. Secondly, the whiteboard.  It's magnetic so I can stick stuff onto it, but it's really more useful as a whiteboard- I'm a big believer that whiteboards are the stuff engineering magic is made of.  I have four of them in my cube at work, and one of the smartest facility design elements I've eve...

In part three, I'll show off my mechatronics tools and parts kit.  Part four will be my workbench and parts storage; that'll probably follow pretty closely on the heels of this since I'm so totally snowbound I really can't do anything else.   It's bigger than it looks.  I had a hard time with this box- it was one of those tool boxes that new homeowners who fancy themselves "handy" buy, which are inexpensive, totally lacking in adequate internal division, and end up full of things like rusty hacksaws, dull chisels, ruined putty knives and inexplicable sheet metal items with flanges and numbered mounting holes. As always, mouse over for labels. Mostly self explanatory; I'm going to mention a couple of things by name.  First, the Pocket Ref on the left side.  My copy predates Make but you can get it from the Maker Shed.  If you don't own this, you should  It has ALMOST everything you'll ever need to know- from the density and chemical com...

If necessity is the mother of invention, snow day boredom is the drunken dorm-mate who will ultimately get you picked up by the campus police. If you're outside of the Minneapolis/St Paul metro area, you may only be cursorily aware of the current snow-tastrophe .  We've gotten about 12 inches so far (300mm for you post-Imperialists) and are expecting another 4-6 (100-150mm).  I managed to get my car safely embedded into a snowbank off of the snow emergency route I live on (read the rules regarding that here - it's harsh but necessary), and, after digging and pushing out a few more people on the walk home, I got bored. My work has been throwing out shoebox sized coroplast boxes for a while now; and being, as I am, on the verge of collapsing into full-on hoarding behavior, I've been picking them up and carting them home.  I've probably rescued about 800- there's a stack taller than I am at the Hack Factory.  Anyway, I use these things for everything- as boxes ...

Of course, the world is replete with articles like this but I recently had cause to write down my thoughts on the issue and I feel like a little more on it couldn't hurt. Why did I get involved in Twin Cities Maker back in 2009, before there was a space?  Simple- I wanted to be part of a MEATSPACE community of people that likes to make stuff.  It didn't exist, so when I found the group, there was no way I could NOT get involved.  I think people who worry too much about virtual space replacing "real" interactions should look at hackerspaces as a dynamite counterexample.  By definition, the people who are involved in these groups are the most likely to be tech savvy, the most likely to participate in online communities of informational interchange about their hobbies, the most likely to be creative basement hermits, AND YET, increasingly, they are seeking out face-to-face interaction as an adjunct to their online work. The tools, the workshop space, the raw mat...

Some thoughts below on NDAs, patents, and people seeking project help from me when I'm wearing my freelance engineer hat.  A lot of this comes from having followed the Piclist mailing list for about 10 years, as well as reading quite a bit of Don Lancaster's writings on the matter- as well as a healthy dose of professional dignity imparted to me by the conflation of engineering with other highly skilled professions such as law or medicine during college. NDAs Sometimes I'll get a feeler e-mail about someone who wants to work with me, and they start off right away by saying "if you're interested, let me know and I'll get an NDA out to you right away." I don't mind working under an NDA (under certain conditions), but some things about being hit up by it right away like that scare me: Once I sign this NDA, if I subsequently complete or publish a project which is remotely similar to this person's idea, there is a legal document which could caus...

Adafruit had a post a few weeks ago about building a cyclorama to take nice pictures of your work.  I built one up for the office (we always have horrible pictures of things in our documentation), but for home I can't justify even the $50-75 one would cost me.  So, I did what any good maker will do- hit the junk piles! First, a word on sourcing:  the local IKEA has a section right before the checkout called "As-is".  (My wife and I frequent IKEA for some reason- we eat breakfast there about once every couple of weeks, and dinner there almost as often.)  As-is is where IKEA goods too good for the trash but too bad to sell as new go- returns, scratch and dent, display models, etc.  Every so often, they'll bundle up a bunch of crap and put it on a "mystery cart" or a "handyman's cart".  The shelves just visible to the right above were a handyman's cart item; the lights all came from a mystery cart.  I've actually bought far too many ...