the same reed switch for two different device

Discussion in 'Homework Help' started by Enrica, Oct 30, 2014.

  1. Enrica

    Thread Starter New Member

    Oct 30, 2014
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    If a reed switch is used from a device1, how can I use the same reed switch with a device2?

    I do not know anything about the device1.

    I'm building a device2 that need use the reed switch.


    Bye
    Enrica
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Need more information about what Device1 is: How is it powered? Is it earth-grounded?
     
  3. Enrica

    Thread Starter New Member

    Oct 30, 2014
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    Device1 is a Black Box, I only know that have the same ground.
     
  4. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    This is sounding like homework, and should be in that forum.

    Are you allowed to make measurements on Device1 before you design Device2?
     
  5. Enrica

    Thread Starter New Member

    Oct 30, 2014
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    No I only know that have the same ground
     
  6. wayneh

    Expert

    Sep 9, 2010
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    Your question is unclear. Do you want to use a reed switch removed from Device1, for use in Device2 that you are building? Or do you want the reed switch to simultaneously perform its original function in Device1 while also switching something in your Device2?

    One feature of a switch is that the voltage across it changes dramatically when the switch changes state. A clue to consider.
     
  7. Enrica

    Thread Starter New Member

    Oct 30, 2014
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    I need the reed switch to simultaneously perform its original function in Device1 (black Box) and Device2.
    Is it possible?
     
  8. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    If device1 is a blackbox, what is in device2?

    Bertus
     
  9. wayneh

    Expert

    Sep 9, 2010
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    I would use a high impedance sensor such as a comparator to sense the voltage across the switch in its original function, and then perform my Device2 switching based on that high impedance signal.

    You must use a high degree of isolation between the devices, since one is a black box.

    Is this a mental exercise or a real project? Can you take measurements on Device1 (such as the voltage being switched) ? Can you learn the switch's ratings for voltage and current?
     
  10. WBahn

    Moderator

    Mar 31, 2012
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    Also, just because a device is grounded says nothing about whether either side of a particular switch within that device is grounded.
     
  11. hobbyist

    Distinguished Member

    Aug 10, 2008
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    Sure there are many ways to configure this outcome,

    in order to give exact details there needs to be a total description of the function of the reed switch in each individual circuit.

    Without that information, nothing can be considered.

    For a complex outcome, here is an example:

    if you would like the reed switch to be used periodically to switch signals in and out of circuit 1, and simultaneously have the option to use the same reed switch to switch signals in and out of circuit 2, then the reed switch would be configured as data routing switch meaning the reed switch could be used as the input to 2 (2 input AND gates), where a clock signal can be present on the circuit 1 AND gate and the reed switch used to direct input signals into circuit 1, then disconnecting the clock signal from AND gate of circuit 1, and clocking a signal into circuit 2 AND gate the same reed switch would then redirect its data input into circuit 2. and vise versa.
    The reed switch is directional depending on the clock signal to each AND gate it is connected too.

    The reed switch could be connected to a sereil shift register to input strings of data into each circuit, dependant on the clock signal. You get the idea.

    Note:
    the actual physical connection of the reed switch itself may need to be implemented with transistor circuitry to keep everything in proper electrical isolation.

    the reed switch could connect to 2 diodes connected to 2 transistors at the base, for proper signal isolation, and design circuitry to turn on the transistors to each AND gate individually when clocked, and so on.. there are so many ways to design this circuitry, from simple steering to complex signal routing, depending on how the reed switch is going to be used.
     
    Last edited: Nov 6, 2014
  12. hobbyist

    Distinguished Member

    Aug 10, 2008
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    Example:
    here is a non complex solution for data routing using one switch (clock input) to steer the data and the other switch (space) to input data.

    Note: the switch labled "space" is used to represent the reed switch action.

    circuit 1 at the bottom will turn on when the switch labled "space" is closed and the switch labeled "C" is opened.
    circuit 2 is activated when the switch labled "space" is closed and the switch labled "C" is closed also.

    This will only allow one circuit to operate at a time

    If you wanted the option to also input to both circuits simultaneously than some more circuitry would be added to activiate another switch option, and so on..

    reed switch.jpg
     
    Last edited: Nov 6, 2014
  13. JoeJester

    AAC Fanatic!

    Apr 26, 2005
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    Post your original problem statement. The source document.
     
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