Windscreen motor project

Discussion in 'The Projects Forum' started by philjt, May 21, 2014.

  1. philjt

    Thread Starter New Member

    May 21, 2014
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    Hi,

    Im new to this forum and to electronics so please forgive my ignorance.

    The project I want to do is very basic (atleast thats what Ive been led to believe)
    I have a windscreen wiper motor which I want to wire up to a switch so that when the switch is activated the motor completes one whole rotation and stops in its park position. I have followed the you tube video http://www.youtube.com/watch?v=1Ww5-pmiokc
    which has been helpful but its not everything I need. I assume I may need a relay thrown in the mix but am not entirely sure how to implement this. The switch I intend on using will either be a microswitch or a tactile switch.

    Any suggestions or help would be appreciated.

    Thanks
     
  2. inwo

    Well-Known Member

    Nov 7, 2013
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    Use an SCR.

    When you trigger it, it will stay on until home switch opens circuit.
     
  3. philjt

    Thread Starter New Member

    May 21, 2014
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    Thanks for the reply, Ill look into this. CHeers
     
  4. inwo

    Well-Known Member

    Nov 7, 2013
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    Sorry, I must be half asleep.

    All you need is the switch.
     
  5. philjt

    Thread Starter New Member

    May 21, 2014
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    So just a simple switch and thats it? Because when following the youtube video I need to hold down the button (switch its really a button) for the motor to completes full turn. Once it reaches park it stops but I cant activate it again by releasing and pressing button again.
     
  6. inwo

    Well-Known Member

    Nov 7, 2013
    2,433
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    Like this.................................
     
  7. inwo

    Well-Known Member

    Nov 7, 2013
    2,433
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    Yes, that's how they are wired in normal operation.

    2 wires and a ground.

    One wire to +12.
    The other wire is momentarily connected to +12. Just long enough for motor to leave "park".
    A micro switch may handle the current. Tactile switch, no.

    I have to admit. I didn't watch the video.
     
  8. philjt

    Thread Starter New Member

    May 21, 2014
    13
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    Thanks for your help, its not an overly complex project but since I have little electronic experience I needed some help. Thanks

    So no wires connected to the park terminals on the motor?

    Sorry Im not great at reading schematics.

    Could you explain the part circled in attached diagram. Sorry.
     
  9. inwo

    Well-Known Member

    Nov 7, 2013
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    My diagram is for a generic 1 speed motor. (2wires and ground)
    The outer circled parts are the motor wires.
    The middle part is the internal park switch.

    It may not be correct for you're motor.

    To go further I'll need the actual motor you're using and the way you want motion to start.
     
  10. philjt

    Thread Starter New Member

    May 21, 2014
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    I have a motor from a mitsubushi mirage, it has four terminals from what I have played with it appears to have a low speed, high speed and two others which from my research are the park terminals.

    I want motion to start by activation of a push button (so is pushed once and released), motor to turn one whole turn and park at its starting position. If the push button is pressed again it starts again.

    This setup is going to be used to reset some steel targets for rifle shooting.
     
  11. inwo

    Well-Known Member

    Nov 7, 2013
    2,433
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    The video seems correct for your motor.

    Switch only needs to be pressed until motor rotates off park position. It will then finish the rotation.

    If you need operation from a quick press, then more circuitry is needed. Otherwise follow the video.

    A "time delay off" relay will stretch input pulse and carry motor current. Allowing you to use a small switch.

    Ebay is full of these relays. Most are mislabled (TD off but are interval) and the rest only have 3A contacts. I'm trying to find one for you.
     
    Last edited: May 21, 2014
  12. philjt

    Thread Starter New Member

    May 21, 2014
    13
    0
    Thanks for the help. I have followed the video but I have to hold down the button for the complete rotation. Ill look into it some more but wasnt having much luck. I really appreciate your assistance.
     
  13. inwo

    Well-Known Member

    Nov 7, 2013
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    Are you using a SPDT switch as in the video?

    It's show upside down. The switch is normally down. Momentarily move up to start.

    How long up depends on moving off park.

    If you get that to work, here is one that uses small SPST switch and delay off to allow shorter "press". Uses a relay as mentioned in video.

    It won't work until you prove the video circuit.

    ps.
    Thanks for hanging around. :) It often takes a week to get this much discussion.
     
  14. jim2618

    New Member

    May 21, 2014
    8
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    guys i dnt knw how to post a new thread.. i need help in my project... i want to control speed of bldc motor without sensors .i am using arduino mega 2560 for pwm..but i cant find the proper circuit for it.. i need an alternative for esc infact... help plzz
     
  15. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,507
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    I guess you found out how!:p
    Max.
     
  16. philjt

    Thread Starter New Member

    May 21, 2014
    13
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    Thanks once again for the info. No I wasnt using an SPDT switch, it was a simple push button switch (all I had lying around). That schematic is confusing for me but Ill try my best.
     
  17. inwo

    Well-Known Member

    Nov 7, 2013
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    I'll redraw it for you later when I get back from a call.
     
  18. inwo

    Well-Known Member

    Nov 7, 2013
    2,433
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    This may not be any more clear, but at least I can redraw it to answer questions.

    It takes a 4 terminal switch. 2 open when pressed and 2 close when pressed.
     
  19. philjt

    Thread Starter New Member

    May 21, 2014
    13
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    Great thanks for the drawing, can I just clarify some things. PS I tried wiring it up again (per the video) and couldnt get it to work. I tried a few different wiring combinations but could not get it to rotate a whole turn without holding down the button. I assumed I could press the button and once the motor began, the internal switch would activate and route power to the motor until it parked. Am I wrong?

    Clarify:

    1. Battery (+) wire to switch (call it A) and park terminal or motor
    2. Wire from switch side A to other park terminal of motor
    3. 2 wires from switch (call it B) to terminal on motor which supplies power to motor
    4. Battery (-) to chassis of motor

    Can you confirm if my interpretation of the wiring diagram and the flow of current is correct. (See attached picture)

    Press the button and supply power to the motor, at some point the motor triggers the internal switch which routes power to the motor until it reaches park and the internal switch is changed.

    Also what switch are you suggesting to use? One like this? http://www.jaycar.com.au/productView.asp?ID=SM1038&w=SPDT+Switch&form=KEYWORD

    Thanks once again.
     
  20. inwo

    Well-Known Member

    Nov 7, 2013
    2,433
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    I believe your interpretation is correct.

    Current path you've drawn is correct, and shown in the unstable mode. Motor is running, and will run until park switch toggles.

    The linked switch will work. I would not expect it to last long, as it carries full motor current.

    Haven't found a suitable push switch.
     
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