Need design for circuit; willing to pay!

Discussion in 'The Projects Forum' started by stjds1, Jul 2, 2011.

  1. stjds1

    Thread Starter New Member

    Jul 2, 2011
    I'm an aero engineer and am currently working on a hobby project that requires a circuit. I'm a pretty good programmer but haven't done circuits in years. I need a circuit design that basically behaves in the following way:

    1) 2 switches A,B
    2) if switch A is closed AND switch B is open then set output high after a set amount of time in seconds.
    3) if switch A is closed AND switch B is closed then set output low
    4) if switch A is open AND switch B is open then set output low
    5) if the output is high then turn on an led light, if low the leave led off.

    I basically want to put this together in a circuit simulator program and then on a bread board for actual testing. I am willing to pay anyone for their time to design the basic circuit for me... email me and we can make a deal! Thanx!
  2. MrChips


    Oct 2, 2009
    Your specification is incomplete.
    What happens if A is open and B is closed?

    In any case, I can create a design using a bunch of logic gates and a 555 timer

    or using a single MCU chip with no other external components (except for the LED and current limiting resistor).
    Last edited: Jul 2, 2011
  3. Wendy


    Mar 24, 2008
    You are basically describing a XOR gate and a monostable so far. Mr. Chips has asked a pertinent question though.
  4. DerStrom8

    Well-Known Member

    Feb 20, 2011
    I just wanted to mention that members here generally do not require payment for such requests. If they are able to help you answer a question, they will. No need to say that you are willing to pay ;)

    Oh, and to answer your question, I would DEFINITELY use a MCU. Much simpler and easier to use. Also doesn't take up much space. As Mr. Chips said, all you would need for a circuit is the microcontroller, two switches, an LED, and a few resistors. Everything else would be written into the program.

    Der Strom
    Last edited: Jul 3, 2011
  5. #12


    Nov 30, 2010
    Looks like a job for two SPST switches and a 555 timer from here, but why miss the chance to program an MCU? If stjds1 ever comes back and clarifies the request, we can procede.
  6. Zod

    New Member

    Jul 3, 2011
    Don't need an MCU for this one, lol ;)

    I was thinking NOR gate and a pair of pull down resistors, with an R/C circuit for the delay on the LED.

    Bit more going on though..

    Truth table:

    1 0 1
    1 1 0
    0 0 0

    Missing is 0 1..
    Last edited: Jul 9, 2011
  7. Ron H

    AAC Fanatic!

    Apr 14, 2005
    So far, that's an XOR, not a NOR.