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  1. BobK

    12v LED Strobe Controller

    Yes, nice circuits. But I can't help but make my usual comment: A single 8-pin PIC would replace all of the flashing control circuitry and allow for additional patterns, and sequences via programming. Bob
  2. BobK

    Voltage limiting without altering waveform

    Kris, Isn't that going to allow about +-8V to the sound card with 9V power? Bob
  3. BobK

    LED Numerical Display Circuit

    I assume that you mean the the microcontroller will connect to the first display board, and it will connect to the next etc. The key would be designing the 2 digit display that you would then be replicating 28 times. How far are they going to be apart? This would affect how the data would...
  4. BobK

    in need of a really simple audio amplifier

    No, a speaker receives continuously varying voltage, not a seried of pulses. Bob
  5. BobK

    LED Numerical Display Circuit

    This is a microcontroller project for sure. What is your level of experience? In electronics, microcontrollers, and programming? Bob
  6. BobK

    Signal help

    Not sure how you get 1420MHz from a 0-1GHz signal generator. (1000MHz = 1GHz) Do you realize that these frequencies are way too high for microcontrollers? Do you realize that things operating at this high a frequrencies are not cheap? If you can find something for $400, buy it! Bob
  7. BobK

    Voltage limiting without altering waveform

    Why do you think you need this? No oscilliscope I have ever owned did it. If you set the range to 100V and the waveform on the display exceeds 100V you know that the waveform might be altered by cliipping, and you turn down the sensitivity until it is within range. Bob
  8. BobK

    How To? Remote Control Sound Effects

    Making someone think they are hearing voices is a stretch. Not likely to succeed. But here is a good electronic prank: http://www.instructables.com/id/The-555-Electronic-Cricket-Prank/ I have not built this, so I don't know how well it would work, but, having tried to locate real...
  9. BobK

    12v LED Strobe Controller

    "Wig Wag" and "three times fast" are not precise terms. What Kris is asking for is what we call a timing diagram in electonics. This shows, on a graph, the behaviour of each signal of interest. You do not have to get that formal, I will try to interpret what I think you are saying, and then...
  10. BobK

    Genius! Please tell me the theory which apply on this

    It is s trickle charger at 0.1C. The voltage will only have to rise a small amount to keep 70ma goling through the battery indefinitely. Bob
  11. BobK

    Problem with programming PIC multiplexing

    You need to specify the oscillator in your configuration word. Try adding & _FOSC_INTOSCIO to the __CONFIG directive. This selects the internal oscillator. I won't comment on the problems with your wiring since you asked me not to. Bob
  12. BobK

    Connecting a stepper motor to an Arduino board

    I hope you are not expecting to drive the motor directly from Arduino outputs. Bob
  13. BobK

    Magnet coil help (turns, gauge, for coilgun)

    Well, start buying up those disposable flash cameras! Bob
  14. BobK

    Magnet coil help (turns, gauge, for coilgun)

    Maybe we should have a coil gun contest. First one to pierce a cardboard target wins. Of course the projectile and target would have to be specified to put us all on equal ground. Bob
  15. BobK

    Magnet coil help (turns, gauge, for coilgun)

    "Roll out the barrel..." Bob
  16. BobK

    Connecting a stepper motor to an Arduino board

    A quick search shows these all over the net, it looks like a take-out from HP printers. But no one seems to have voltage / current specs. Bob
  17. BobK

    Magnet coil help (turns, gauge, for coilgun)

    Slingshot ammo does not travel at 2000 ft /sec. And there is a good reason for using a sphere in a sligshot. Without a barrel any non-spherical shape would tumble and travel in nothing like a straight line. Bob
  18. BobK

    driving a relay

    Same calculation. Use the output high voltage of the IC where I used Vin, and make sure it can source the required amount of current. Bob
  19. BobK

    Magnet coil help (turns, gauge, for coilgun)

    Whoops, my previsous calculation was off a bit. Four layers would use up on 120 inches of wire, not feet! It will take 19 layers and the outer diameter of the coil will be 3 inches. You should start with the desired muzzle velocity. Then you can calculate the forces needed to to...
  20. BobK

    Capacitor scrap metal

    Well, they are better for drilling! Bob
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