antiquus

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antiquus

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  • 03.17.2017
  • Your other hobbies: Engineering-like?
  • Yes, I think that engineers tend to be musicians, although many were high-school-only, and have fallen behind in their practice. As for myself, I'm the drummer in http://www.territorialbrass.com, and a number of other local bands. its definitely a hobby -- sometimes we're paid enough to cover gas for the car. Like you, I also have a ham license with dust on it. I've been trying to become more active in local STEM operations, and have volunteered as a science fair judge a number of times, or demonstrated electronics at school STEM events.
  • 04.21.2016
  • The skinny on LED strips
  • I am also working on an LED lighting project, but I'm using the 5 meter strips with WS2812 3-color LEDs. Like yours, the strip came from China and included a controller, but these operate at only 5V. The spool looks very much like your picture. Following your lead I measured the voltage, and there is about 1V loss from end-to-end when I had the "white" option enabled, and the spool was becoming warm to the touch. When I connected the far-end power leads to the 5V supply, the lights became somewhat brighter. In my case the strip is covered by a vinyl sleeve because it will be used out-doors, so I cannot connect to the midpoints. But I intend to run them at less than full power, and probably only one or two colors at a time, so I expect that these will be OK in my application, even when local ambient reaches 50C. I see now that I should plan to put an extra wire to the far end of the strip when I install them. That will be OK because I was trying to figure out how to make them less visible, and a black 2-conductor cable will hide the edge.
  • 04.10.2015
  • 10 Questions to ask during code reviews
  • #4 should also ask about the use of _volatile_, and _const volatile_. The former is used for communication with interrupt service handlers, and both are used for hardware register values.
  • 12.01.2014
  • Standardized tests versus creativity
  • The students that do well in STEM are not the students having trouble with tests. The to-be engineers are still the top few percent of all students, and I dare say that none is washed out by the MCAS or any other get-out-of-high-school requirement. You have but to judge the Intel science fair (or any other high-level competition), to see that those that will be engineers and scientists step through any academic requirement as a necessary evil. Study for a few minutes, and realize that American schools are the very worst at using available data, especially those data that will eliminate the incompetent teacher. Note how many elementary schools are bringing in "math specialists" to achieve the goals required by the tests, because the typical elementary teacher can barely perform arithmetic, let alone teach it. The clamor over Common Core techniques has as much to do with the need to teach strategic arithmetic (e.g., why is repeated addition the same as multiplication), in lieu of tactical arithmetic (e.g., just memorize that 6x9=54).
  • 12.12.2014
  • Tale of two thermostats: Nest teardown
  • Your analysis did not include the data transmitted by the thermostats. I do not have either version, but I do have the Honeywell model without the color display. The device transmits only encrypted data. The connection to a smart phone is handled through the cloud, and you are obligated to use that service. To my knowledge there is no API, so if you expect to log equipment activity you are out of luck. With Apple's track record, I doubt they are any more "connectable". I bought this unit because I had 2 Trane thermostats die in about 12 years. Even with high pin-count devices, the reviewed devices give me a much better feeling of well-constructed (unless you consider "good" engineering being to take back the very last penny of parts and assembly costs). At least the PCBs are epoxy-glass.
  • 12.05.2012
  • Don’t talk to me about Windows 8!
  • When I built my first Z80 (wire wrap) board, my father looked over my shoulder and said "What good is it if you can't update the microcode?". I agree with @chudson: another age is dawning.
  • 06.14.2012
  • Could a Klingon cloaking device really be developed?
  • Another question occurs with regards to the bandwidth. In the earlier device, the bandwidth is 1500-2600 micrometers, which your readers will understand is nearly 1 octave. Your radar-acquainted readers will recognize this as barely commendable performance. However, your article says only that the range now extends to 700 um, but does not say if the 1-octave bandwidth is retained, or if the effect still operates to 2600 um. Having a 4-1 bandwidth (2 full octaves) would of itself be quite interesting. A follow-up note in the June, 2010, issue of Science clearly indicates that leading physicists expect applications to be limited to very small perturbations (not space ships), with a refinement to that statement in the July letters to the editor. As earlier stated, the news here is that someone can lay down sub-micrometer structures of known refractive index in a well-controlled pattern, and that an optical TDR exists with resolution to micrometers. Although much less glamorous than Klingon-cloaking, most of your readers deserve better than the Nickelodeon version.
  • 06.14.2012
  • Could a Klingon cloaking device really be developed?
  • OK, so I did a little research. This group reported a similar near-infrared device in "Science" magazine, March 2010, with a summary in "Science News" magazine as well (May 2010). Those articles suggest that the "cloaking" happens only along the long axis of the device illustrated in the picture, and is limited to hiding that little bump in the top cover. The "multidimensional" aspect of it is unclear. The device works when the observer is looking into the end of the stack (the short end, not the broad side suggested by the picture). In practice, the technique guides light that is traveling perpendicular to the bump (or groove) that can be seen penetrating down into the stack of rods. I only have full access to the Science News article, and it reports data from 1500-2600 micrometers (wavelength), and your article indicates that this is now extended to 700um (visible red). However, neither that nor your article propose that conditions at the far end of the waveguide are visible, but only that the reflections from the bump are hidden. In other words, it could just be a smoothing of the transmission impedance in the region of the bump, and not necessarily true transmission wave guiding. As your readers will know, impedance changes like this are normally spotted by a TDR, so the bump is hidden in the sense that it does not appear in a TDR trace. Beyond that, the articles say nothing. An interesting point is that, clearly, the "rods" must be deposited before depositing the "bump", so it is necessary that the rod pattern must be determined with a priori knowledge of the bump, or at least the region that will be hidden. On the plus side, this suggests that the rod pattern can be used with or without the top cover (the tan cover seen in the photograph), so in some ways may eventually be portable.
  • 06.27.2012
  • The EC’s new marketing tactic? Sexism
  • You're all thinking like grown, self-assured adults. Now imagine yourself as a 10yr old girl looking beyond the box full of Barbies. Is it worth doing your maths homework, or building up a science fair poster? Having one brain cell that links glamour with science is probably not a bad thing.
  • 06.12.2012
  • Adding Intelligence to LED Lighting
  • By altering the building to 12VDC, you are implicitly raising distribution currents by 10x (in the 120V countries), or by 20x (in 240V countries), assuming luminares of identical power rating. Heating of wires in conduit is already a principal issue in any building wiring, and that heat is determined by the current irregardless of voltage. Wire temperature is currently the limiting factor that determines conduit sizes and the number of conductors within each conduit. To prevent a significant change in wire temperature, a tremendous increase in conductor size will be required (more copper), followed by a corresponding increase in conduit size (more steel and far more difficult installation). This should be placed high on your list of disadvantages.