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  1. BobK

    Multitasking an Arduino

    The simplest form of multitasking is called a state machine. This can be used on any microcontroller. http://www.eetimes.com/document.asp?doc_id=1271837 Bob
  2. BobK

    Transistor Question

    If those are the only differences, you can safely substitute the G for the C. Bob
  3. BobK

    How to get a strong signal over a long distance

    A microcontroller does not do anything out of the box. You program it to do what you want. Bob
  4. BobK

    voltage divider with diode

    A reasonable amplifier will have a source resistance of way less then 1 Ohm. You really do not want maximum transfer of power, or your speaker would be < 1 Ohm impedance. In fact, the ratio of the speaker impedance to the source impedance is called "damping factor" and higher is considered...
  5. BobK

    micro controller design

    I would question the 8-bit instruction word. Also external program memory and RAM, most micrcontrollers do not have this, is there a reason you do need it? What is the purpose of this exercise? Surely you don't expect to compete with available microcontrollers. Is this a school project? Bob
  6. BobK

    Transmitter/Receiver frequency

    That was not advice, it was an answer to your question. For advice, you would have to tell us what you are trying to do. Bob
  7. BobK

    1.2 V Power Supply Voltage drop

    Just add a pass transistor and get it over with. Bob
  8. BobK

    Transmitter/Receiver frequency

    For a single frequency, you could use a crystal. Bob
  9. BobK

    Smallest led controller

    I just looked at the chip Steve suggested. Are you looking for a bar graph type display, i.e. more LEDs light up as the audio gets louder, or just having the entire strip change in brightness with the level of the music? Steve seems to have assumed the former, and I the latter. Bob
  10. BobK

    Arduino turning a knob left and right with Digital PWM

    Perhaps you could replace the pot with a digital pot. Bob
  11. BobK

    Smallest led controller

    +1 on the microcontroller. Microchip has 6-pin chips are are practically microscopic. Bob
  12. BobK

    RF Transmitter/Receiver help/possibilities

    Look on Ebay for wireless remote control module. Bob
  13. BobK

    how different Power Resistor will affect my circuits

    A different load will definitely affect how much current is drawn by a DC-DC converter. But your currents are way out of whack. 15V into 330 Ohms is 0.68W, 0.5A at 24V is 12W, so your converter is operating at 5.6% efficiency. Something is wrong. 15V into 22 Ohms is 10.2W. 1.7A at 24...
  14. BobK

    Help with huge LED circuits

    You are much better off using a higher voltage and series / parallel connections. If you connect all of them in parallel, then the current required is 40 x 20mA = 800mA . Whereas, if you use say 12V and put 5 LEDs in each series string it is only 8 x 20mA = 160mA. Each series string would...
  15. BobK

    Virtual grounds

    It is often best to make a buffered virtual ground. You set up one op amp as a voltage follower (output connected to - input) and you connect the + input to a voltage divider at half the battery voltage. The output of this opamp is then your virtual ground, and all connections to ground are...
  16. BobK

    Schmitt trigger relaxation oscillator

    See this thread, it is about the same circuit. https://www.electronicspoint.com/diode-and-capacitor-basic-questions-t267394.html Bob
  17. BobK

    Hybrid Electric Engine

    If I understand it correctly, when running under electric power, you are pushing the pistons of the ICE as well since they are connected to the same crankshaft. This seems very inefficient to me as all of the friction in the ICE pistons is simply wasting energy. I my Prius, when the electric...
  18. BobK

    pic 16f877a program problem

    Are you saying you want to microcontroller to read a value that is displayed on a 3 digit 7-segment display? Bob
  19. BobK

    Power Supply

    I think that second supply is intended to be used in a lighting fixture and might not be isolated, since they call it an "electronic transformer." If you use it like you would a transformer, your PCB might be at line potential, which is, of course, dangerous. Bob
  20. BobK

    Relay Problem

    1) The 1M resistor is providing hysteresis. When the circuit switches to on, because the the - input is lower than the + input, it raises the plus input a little bit, so that it does not go back and forth when the voltages on the + and - are the same. When it goes off, it does the reverse...
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