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  1. hevans1944

    Remote sensor on powerline

    Yes, indeed. The oscillator transmitter injects about 100 kHz low-level signal onto the power line by capacitive coupling. General Electric invented power-line carrier signaling, IIRC, and it works just fine. The X10 product line uses this same technology, somewhat improved by adding a wireless...
  2. hevans1944

    Why don't I get a Sine wave?

    I like LC oscillators, and they generate "pretty good" sine waves, but the microprocessor/DAC look-up table (LUT) approach is simple and, with plenty of data points per cycle, doesn't require very much filtering. IMO, the major limitation is how fast you can cycle through the LUT, which places...
  3. hevans1944

    Would this transistor work?

    A few years ago (circa 1996) I had the good fortune to be employed in a lab that had a low-energy, high-current, ion implanter. One of my tasks was to keep it operational, but It mostly stood idle since the people who actually used it to dope semiconductor wafers had long before then moved on to...
  4. hevans1944

    Would this transistor work?

    No, it does not work.
  5. hevans1944

    Why don't I get a Sine wave?

    Trying to recover just the fundamental sinusoidal frequency from a square wave, or even from a triangle wave, is the long way around the barn to generating sine waves. It is a lot easier, most of the time, to construct a sinusoidal oscillator in the first place, as @Harald Kapp suggested in his...
  6. hevans1944

    Why don't I get a Sine wave?

    The last amplifier isn't really an integrator because there is a resistor in parallel with the "integrating" capacitor. This resistor is the reason the output is "curvy" instead of a a linear saw-tooth waveform. But since you are feeding square waves into your "integrator" stage, by what magic...
  7. hevans1944

    electromagnetism

    I am drinking an organic coffee imported from Ethiopia: Amaro Gayo. Didn't realize it contained a dose of optimism, but if that is so, I am sure it isn't synthetic. Very tasty coffee IMO. Rewarms in the microwave without loss of flavor or taste. Seasonal though; you have to purchase enough to...
  8. hevans1944

    Hooking up deadbolt motor to TB6612FNG Stepper Motor Controller

    It's a switch, either open or closed, and that means there are only two states to sense: 0 or 1. A digital input is designed to accommodate this. If one terminal of the switch is Gnd (or circuit common) you connect that to your microprocessor digital common. Connect the other input to a...
  9. hevans1944

    electromagnetism

    It would help a lot if you described in some detail what that "compass vane like (metal chip) of a 2 mm diameter" actually is. Does it pivot to allow it to be flipped? If so, how does it pivot? Is it magnetized? If magnetized, is one face one pole and the other face the other pole? How do you...
  10. hevans1944

    electromagnetism

    Sounds like you have a pretty good and practical understanding of inductors. Unfortunately none of our responses here have elicited any information from the OP about what they are actually trying to DO, so this thread is leading nowhere. BTW, it is not uncommon for us human beans to be wrong...
  11. hevans1944

    Shorting a Battery

    If you ever do get your socks working with sufficient battery life, maybe you should shoot for the market this company addresses. Spending $300 for a pair of heated socks may sound a bit outrageous, but if they work well and you need to keep your feet warm while skiing in the Alps, that's...
  12. hevans1944

    Detecting Leveling of Arm and Shoulder

    The article that Bob cited has an extensive list of references to pursue. Following just one of them, led to this paper where the authors did an extensive review of IMU methods. The review is six years old, so you may want to search for something more recent. The authors' conclusion is probably...
  13. hevans1944

    electromagnetism

    Sorry, Chris. If you feel the need to scroll, check out post #11. Your reply in post #12 probably nailed it. I have seen electromechanical annunciators that use electromagnets to flip vanes to display, for example, sports scores. These are usually quite large because they are viewed from afar...
  14. hevans1944

    electromagnetism

    When the ferromagnetic core of an inductor saturates, the main thing that happens is the relative permeability of the core approaches unity. The induced magnetic field at this point still exists, and an increasing current in the inductor will slightly increase the strength of the magnetic field...
  15. hevans1944

    Detecting Leveling of Arm and Shoulder

    So, unless someone here can find a faster IMU or another method, it looks like you are SOL for a solution. I do know that the maker community has fully embraced this technology for building things like 'copters and robots and such, and modern cell phones use it to determine orientation of the...
  16. hevans1944

    running the hantek 1008c

    Have you visited any of the links on this Google results page? Read the instruction manual? Try building on a solderless breadboard a simple 555 oscillator circuit. Look at the pulses on the output and the saw-tooth waveform across the timing capacitor. Play with the RC values and observe the...
  17. hevans1944

    Detecting Leveling of Arm and Shoulder

    Is the upper arm the part between the elbow and the shoulder? Or is the IMU mounted at the wrist on the forearm? If it works for slow motions, then the data rate is either too slow to detect the change in rate gyro output for faster motions, or the response of the rate gyro is too slow. Are you...
  18. hevans1944

    Detecting Leveling of Arm and Shoulder

    @Minder: mercury? really? in a glass caspsule? I would think the inertia of the blob of mercury would affect the horizontal reading. Could the OP provide a specification or model number of the IMU? What is the minimum and maximum rate of change of rotation (degrees per second) that the rate...
  19. hevans1944

    Shorting a Battery

    I can understand why you would want to make versus buy a sock warmer, especially after looking at this Google search result. These things are all over the map in terms of quality and cost and battery lifetime. If you are going to use these socks on the road to keep your feet warm, then using...
  20. hevans1944

    bridging ribbon wire

    This might be repairable with individual strands of insulated wire bridging the part that is damaged. All depends on what the "painted on" conductors are made of. If tin-plated copper, it is doable because the conductors are solderable. If aluminum, you are SOL. BTW, this flexible cable was NOT...
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