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  1. BobK

    50000mah battery - auto power off

    This is not just a battery. It is a 3.7V battery plus a boost converter to get 5V output. The boost converter has a minimum current to work properly. I doubt that there is any easy fix to use it for a 50mA application and not simply waste power. Bob
  2. BobK

    Frequency to Voltage without ICs

    You are already using an Arduino. It is capable of doing frequency to voltage conversion. Why would you need an external circuit? Bob
  3. BobK

    Changing Signal Frequency And Frequency Overtones Respectively

    Okay, say the string is mistuned and it is playing an F# when it should be playing an Eb. How do you convert it to Eb? Bob
  4. BobK

    C program .cpp file encryption

    Going back over 30 years, to the original "Adventure" program, The strings that it recognized were all in plain text inside the .exe. I and others cheated by reading these looking for words that it might respond to. So, I would recommend that you do not use literal strings in your program that...
  5. BobK

    Changing Signal Frequency And Frequency Overtones Respectively

    In addition to the problem Hop stated in the interaction between strings, there is another more fundamental reason that your scheme would not work. If the string could be tuned off by 1/2 a semitone or more, you could not determine which note it is actually playing to correct it. Not to...
  6. BobK

    LC Oscillator

    Here is a Colpitts oscillator that works in LTSPICE. I can only get it up to a few 10s of MHz by tweaking. To get the 1.5GHz would require a specialty transistor and circuit. Bob
  7. BobK

    Extremely basic circuit help required!

    If the box is metallic, connect the ground wire to the box. Otherwise, leave it unconnected. There is not much point in using a fuse in line with a light bulb. The bulb will act as a fuse all by itself. Bob
  8. BobK

    One Way Communication from Chip-to-Chip

    Ask my nieces and nephews! :) Bob
  9. BobK

    One Way Communication from Chip-to-Chip

    Originally you wanted to control 1 relay. Now you want to control 2 LEDs. The solution is different for these 2 different problems. Bob
  10. BobK

    Transistor switching on another voltage supply

    Colin gave the answer in post #2. It is the same one I would have given. Bob
  11. BobK

    One Way Communication from Chip-to-Chip

    I agree with the other two. Connect an output port of the sender to an input port of the receiver. In the sender, put out a high when you want the relay on and a low when you want the relay off. In the receiver, check the input port periodically. If it is high, turn the relay on, if low turn...
  12. BobK

    One Way Communication from Chip-to-Chip

    Okay, you have been given the answer twice then. Bob
  13. BobK

    One Way Communication from Chip-to-Chip

    I am getting the idea that these two chips are separated and not connected and you are looking for something like a wireless connection. Is that true? Bob
  14. BobK

    Basic electronics

    If you apply 230V to a heating element that is 0.001273Ω you will do nothing more than blow a fuse. Bob
  15. BobK

    needs help about attract electromagnetic wave

    I seriously doubt that. Bob
  16. BobK

    Help with a sample code of sun tracking with Arduino Uno

    The square brackets were interpreted as bb-code commands. Bob
  17. BobK

    How to control 80 relays using ardrino

    Here is an example of a relay you might use: http://www.digikey.com/product-detail/en/G5LE-1A4 DC24/Z2254-ND/369017 80 of these would require a total of < 1.5A
  18. BobK

    How does an ATX power supply work?

    It is a switch mode power supply, so you will not find any linear regulators in it. Typically, they use a transformer with multiple windings to get the various output voltages. One voltage is regulated, and the others are simply based on the ratio of turns in their windings. Bob
  19. BobK

    voice module help please

    Did you try what I suggested in post #6? Bob
  20. BobK

    How to control 80 relays using ardrino

    30A is still about 10 times higher than you need. Also, why do you need to power the relay coils when the AC power is off? This makes no sense at all, in fact, it is the opposite of what you should be doing, you should not power then until the power is once again stable. Bob
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