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momentary +12VDC on input to flip the polarity of +12VDC on output for 10 seconds

Discussion in 'General Electronics Discussion' started by TerminatorX5, Oct 11, 2015.

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  1. TerminatorX5

    TerminatorX5

    4
    0
    Oct 11, 2015
    Hello.
    I am new to this forum, and came here to ask the experts...

    My issue -

    input - momentary application of +12VDC to input wire should produce

    output - (+) 12VDC on one output conductor and (-) on the other conductor for specified period of time (10-15 seconds, should be controllable)

    input - momentary application of +12VDC to the same input wire should produce

    output - (-) 12VDC on one output conductor and (+) 12 VDC on the other conductor fro specified period of time, reverse of the first momentary application, and should be time restricted, 10-15 seconds.

    The purpose of this is to operate the power spindles - with one push of button, the spindles will spin in one direction for 10-15 seconds and then stop, with another push of the same button, the spindles will spin in opposite direction for 10-15 seconds and then stop.

    I have tried SPDT, DPDT, timed relays, but I can't get it... I thought, if I can find a DP3T relay, i might accomplish something, but such a relay proved to be rather elusive.

    Can anyone shed some light on this mystery?

    thank you,


    TerminatorX5
     
  2. AnalogKid

    AnalogKid

    2,571
    739
    Jun 10, 2015
    So if the control circuit is powered from the same 12 V that you are sending out to the load, what you want is this:

    First input edge or short pulse = 15 sec normal power output
    Then no power output, indefinite waiting on 2nd input pulse
    Second input edge or short pulse - 15 sec reversed power output.
    If all of that is true, then...:

    What is your skill set, and what are you asking for? Do you want an all relay and industrial control delay timer solution, or help with a small control circuit? Do you want to wire things together, or solder components on a perf board?

    Overall, you need a toggle function, a timer function, and two output relays. The relays can be either off/normal and off/reversed, or on/off and normal/reversed. I think the latter will be the easiest to do with off the shelf control modules.

    Please post a schematic of your current circuit and we can help straighten it out.

    ak
     
  3. GPG

    GPG

    452
    66
    Sep 18, 2015
    What are the spindles? How much current.
     
  4. TerminatorX5

    TerminatorX5

    4
    0
    Oct 11, 2015
    Hi folks.

    I am ok with soldering, ok with wiring (many years ago I even traced my own circuit boards, but it was good 30 years ago...). I can go with wiring and relays, or a control circuit (I'd rather stay away from vacuum tubes!), but for a replicating simplicity I think that relays would be a much simpler solution - once I figure out a solution, (hopefully with your help), I will post the written up guide on the car forum that I frequent, and it may help the other folks in the same predicament to build the same device.

    This entire set up is for an automotive application (actually two not related applications):

    1. The question posted is for operation of two spindles (motorized actuators) for a trunk gate - when the release button is pushed (three possible activations of release - gate handle, remote key button, inside cabin button, the signal is picked up from the lock release mechanism, so all three buttons result in same signal to the locking mechanism). Once a button is pushed once, it activates the lock release and the gate starts to move up, as spindles extend. Given a specific weight of the gate, it would take a specific amount of time to raise the gate. Once the gate is raised, the spindles stop. To lower the gate, a button is pushed again. It will activate the release action in the lock (which is gone in vain, since the gate is not closed), the gate is lowered for specific time, determined by the weight of the gate, once the gate touches the locking mechanism, it activates the "soft close" feature of the lock, which catches the gate and pulls it closed. Thus, a same triggering function (unlock feature of the buttons) should activate two different results.

    2. Second question, that was not posted, applies to the same vehicle with a different device - when the device detects an "ignition hot" voltage, it sends a certain polarity voltage for about 5-12 seconds to external mirrors, and they unfold open. When the "ignition hot" is removed, the same device sends reversed polarity voltage and that will fold the external mirrors. So, this variation operates slightly differently - instead of a momentary pulse of voltage to trigger two opposing results, this one operates on two states of voltage - ON and OFF.

    I have a diagram for the second question (credit goes to a fellow in UK), but for some reason I can't post that PNG file. However, here is link to the original post by that fellow in UK who came up with the idea (at least, that is where i got mine from!) - http://www.xoutpost.com/bmw-sav-for...r-fold-mirrors-my-ignition-auto-fold-out.html You can see the questions that I had posted and the guy had answered them as much as he could...

    My iteration of his diagram is slightly different, and has its own issues, probably due to the components used...

    I am rather active on that car board, and will be more than happy to give a proper credit to creator of the solution.

    Thank you folks

    TerminatorX5
     

    Attached Files:

  5. GPG

    GPG

    452
    66
    Sep 18, 2015

    Attached Files:

    Last edited: Oct 14, 2015
  6. GPG

    GPG

    452
    66
    Sep 18, 2015
    Now that's curious the file got uploaded from gdrive
     
  7. TerminatorX5

    TerminatorX5

    4
    0
    Oct 11, 2015
    Optocoupler??? WOW!
    Which component controls the time duration? The desired time will be determined by field testing, running the the actuators up and down...
    I see the component list as:
    R1 - 1K
    R2 - 470
    R3 - 120K
    R4 - 470
    R5 - 47K
    C1 - 100 microF
    C2 - 100 microF
    D1 -
    D2 -
    Q1 -
    Q2 -

    H11F1
    LM555C - 2 pcs
    SPDT relay
    DPDT relay


    Am I missing anything?

    Thank you for taking time to devise this, I really appreciate it.
     
  8. eetech00

    eetech00

    95
    8
    Nov 17, 2014
    Hi

    You could replace 2 LM555's with a single LM556 and save a chip.
    If you really want the timeouts adjustable, replace the timing resistors with pots.
     
  9. GPG

    GPG

    452
    66
    Sep 18, 2015
    Update. Diodes 1N400x Q1,2 depend on relay current R6 R7 added.
     

    Attached Files:

    Last edited: Oct 15, 2015
  10. GPG

    GPG

    452
    66
    Sep 18, 2015
    R3 C2
     
  11. TerminatorX5

    TerminatorX5

    4
    0
    Oct 11, 2015
    updated Bill of Material

    R1 - 1K
    R2 - 470
    R3 - 120K - possibly a potentiometer
    R4 - 470
    R5 - 47K
    R6 - 100K
    R7 - 100K
    C1 - 100 microF
    C2 - 100 microF
    D1 - 1N400x
    D2 - 1N400x
    Q1 -
    Q2 -

    H11F1
    LM555C - 2 pcs or LM556 - 1 pc

    SPDT relay
    DPDT relay
     
  12. GPG

    GPG

    452
    66
    Sep 18, 2015
    You could use a small MOFET for the relay drivers, Whatever you are happy with,As long as it handles the current without much loss
     
    Last edited: Oct 15, 2015
  13. Colin Mitchell

    Colin Mitchell

    1,416
    314
    Aug 31, 2014
    You have to wait before reversing a motor. The above circuits will not work.

    I have a project called To-Fro that reverses a train.
    It uses a micro and 2 relays. That's what you need.
     
  14. GPG

    GPG

    452
    66
    Sep 18, 2015
    Revision invert trigger.Any small signal NPN will do.
     

    Attached Files:

    Last edited: Oct 17, 2015
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