Search results

Search Forums New Posts
  1. hevans1944

    How do energy plants safely measure power

    Modern power plants do need to measure how much power is being delivered to their transmission lines to determine how many turbine-driven alternators to bring on line at any given moment. The measurements are made remotely using a data acquisition system that monitors line voltage and line...
  2. hevans1944

    suffleboard scoreboard help

    So, each time a player scores a point, they push their button and their stepper advances one notch? The stepper shaft has a pointer attached and this indicates the cumulative score for each player? At the end of the game a third button resets both steppers? Sounds really doable, but you may...
  3. hevans1944

    Problem with 5v power supply

    That depends on what kind of a load you plan on using. Or did you just want to light up the LED (which I presume it does now)?
  4. hevans1944

    suffleboard scoreboard help

    Gee, talk about your "old school" designs... wouldn't you rather have a nice modern all-solid-state counter with a suitable interface to your scoreboard? And how does that scoreboard work? How about some pictures? The stepper you have appears to use two 240 V coils... hard to tell if one coil...
  5. hevans1944

    Sensor ideas

    I think a sensor-glove woven with stretch-fibers that change resistance or perhaps optical characteristics (think fiber optics) could be made inexpensively. But a team of Ukranian students has built something that isn't too shabby... check it out.
  6. hevans1944

    Capacitors in parallel effects on frequency

    Capacitors, by themselves, don't have a lower cutoff frequency. The reactance of a capacitor varies continuously as a function of frequency and can be found, at any given frequency, by means of this formula: Xc = 1 / (2 pi f C), where pi is about 3.1416, f is the frequency in hertz, and C is the...
  7. hevans1944

    Newb Needs Some Guidance

    Why do you want to see the codes that are being transmitted? As the datasheet explains, these codes change for each exchange of data from transmitter (encoder) to a paired receiver (decoder). The encoder in the transmitter is initially paired with the decoder in the receiver by the manufacturer...
  8. hevans1944

    GPS receiver for less than USD 20?

    And here is a web page with a nice description and a link to a schematic.
  9. hevans1944

    help wiring TDA5140A Brushless motor driver chip

    Where is the datasheet for the motor? Why did you purchase the TDA5140A IC? Your LiPo charger circuit will charge a single cell only, not two connected in series. Other than that, it's all plug and pray.
  10. hevans1944

    3-Phase VFD Supply Pre-Filter

    There are several forums on the Web that cater to Chinese VFD three-phase inverters and Chinese air-cooled and water-cooled three-phase spindles. Here is one that you might find interesting. I find it even more interesting that the price on E-bay for what appear to be identical VFD drives ranges...
  11. hevans1944

    Following the sun ( no programming )?

    Probably. I visited a solar-heated model home in Tuscon AZ, sometime around 1979 while interviewing for a job with Hughes. This was a demo model solar installation, part of new housing sub-division. The solar water-heater had maybe fifteen or twenty black-painted tubular collectors, mounted at...
  12. hevans1944

    Members location

    Perhaps you could use member URL and/or ISP to give an approximate location? I just responded to a post with a recommendation to visit Radio Shack, but then realized not everyone has a Radio Shack nearby, or even in their country.
  13. hevans1944

    Small solenoid coils

    Check Radio Shack for reed-relays in small packages. These will have a tiny coil inside to operate the magnetic reed. Of course this assumes you live where there IS a Radio Shack nearby. This is an international forum, so your mileage may differ.
  14. hevans1944

    PIC Compilers

    Well, good luck with that. Please let us know when you find this more extensive solution. I would be particularly interested in micro controllers offered in 2015 and later years.
  15. hevans1944

    Wind farm – payback methods

    Well, cash works for me. Or did you mean how to distribute the income received from selling wind-generated electrical energy to a local utility? Are you assuming there will be any income left after paying interest and principal on the construcition loan, purchase of the land, providing for an...
  16. hevans1944

    Circuit to indicate charge remaining in any battery bank

    The "full load" battery test is available free at Auto Zone to allow you to determine whether your lead-acid car battery is capable of cranking the engine. Monitoring the battery terminal voltage while heavily loading it does provide some indication of its capability, but IMO it is only a...
  17. hevans1944

    Rain Sensor Status

    Well, this has been a very interesting thread. As I was reading it, I was wondering when someone would suggest a relay solution. And of course @KrisBlueNZ did just that. You just keep on trucking @chopnhack! You are definitely making progress. I like the way you are not afraid to try things...
  18. hevans1944

    Circuit to indicate charge remaining in any battery bank

    Linear Technology offers integrated circuit battery management devices capable of operating with any common battery chemistry, the LTC-4020 for example. The user selects the chemistry and charging method during the application design phase. These devices are complicated and should be used with a...
  19. hevans1944

    The art of electronics

    My oldest son, who is an electrical engineer working for a multinational corporation in Atlanta GA, gifted me with the second edition of Horowitz and Hill's "The Art of Electronics" a few years ago. I thumbed through it and thought, "I sure could have used this twenty or thirty years ago!" There...
  20. hevans1944

    Confused about a DC Motor

    Yeah, PWM is another can of worms entirely, but I do like the taste of those worms. Sometime in the last century I was given the task of connecting a Superior Electric stepping motor to drive a large Czerny-Turner monochrometer. This thing had a very large diffraction plate and a one meter long...
Top