Drop Fractional Voltage to Absolute Zero to Disable H-Bridge

Discussion in 'General Electronics Chat' started by MyTPioneer, Apr 30, 2016.

  1. MyTPioneer

    Thread Starter New Member

    Dec 18, 2015
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    I'm trying to wire up an XBOX 360 controller to an H-Bridge, that is connected to a 12v DC motor. The output on the 360 controller is about .002v when idle, and it's causing the H-Bridge to enable the 12v DC motor at this point.

    Is there anything I can do to prevent the .002v from reaching the H-Bridge?

    Thank you for any suggestions.

    DC
     
  2. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    Do you have a pull down resistor on the output of the XBOX?
     
  3. crutschow

    Expert

    Mar 14, 2008
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    That seems to be a very sensitive H-Bridge.
    Try placing a diode in series with the XBox output (anode to output) with a 10kΩ resistor from the cathode to ground.
    Drive the H-bridge from this diode-resistor junction.
     
  4. MyTPioneer

    Thread Starter New Member

    Dec 18, 2015
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    I tried the setup recommended by Crutschow and something is still not right. When I put a multi-meter between the cathode side of the connection and the black wire from the 360 controller, it now reads zero. But when I make the connection to the H-Bridge, the motor still runs and the resistor becomes really hot.

    I'm sure I don't have things set up correctly.

    Here is my setup:
    The 360 controller has a black and red wire coming out of it that used to run to the old shaker motor. I have the black wire going to number 5 (GND). I also have the ground from the 12v power supply I am using going into number 5. The red wire from the 360 controller is connected to Pin 9 (IN 2). The two wires from the 12v motor are connected to 1 & 2. All jumpers are in place. Below is a reference photo to the H-Bridge.

    Any thoughts on where I'm going wrong?

    [​IMG]
    1. DC motor 1 "+" or stepper motor A+
    2. DC motor 1 "-" or stepper motor A-
    3. 12V jumper - remove this if using a supply voltage greater than 12V DC. This enables power to the onboard 5V regulator
    4. Connect your motor supply voltage here, maximum of 35V DC. Remove 12V jumper if >12V DC
    5. GND
    6. 5V output if 12V jumper in place, ideal for powering your Arduino (etc)
    7. DC motor 1 enable jumper. Leave this in place when using a stepper motor. Connect to PWM output for DC motor speed control.
    8. IN1
    9. IN2
    10. IN3
    11. IN4
    12. DC motor 2 enable jumper. Leave this in place when using a stepper motor. Connect to PWM output for DC motor speed control.
    13. DC motor 2 "+" or stepper motor B+
    14. DC motor 2 "-" or stepper motor B-
     
  5. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    Why did you connect red wire to In2? Why not In1? I am not saying it's wrong; I just wonder what your reasoning was.

    I really don't understand why you are using an H-bridge. Are you reversing the motor?
     
  6. MyTPioneer

    Thread Starter New Member

    Dec 18, 2015
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    I used Pin 2 because I recycled a connector that I had and it only had a wire coming out of 2-4, so I started with 2. I used an H-Bridge because I had one laying around and thought that was the way to go. I'm open to other suggestions to power a 12v motor using the 1.8v signal that comes out of the 360 controller.

    Thank you for all of your input.
     
  7. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    So, you do not need to reverse the motor?

    You only need to run it one direction...correct?
     
    Last edited: Apr 30, 2016
  8. MyTPioneer

    Thread Starter New Member

    Dec 18, 2015
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    Correct. One direction is all I need and either way is fine. My 12v motor is taking the place of the much smaller original shaker motor.
     
  9. tracecom

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  10. MyTPioneer

    Thread Starter New Member

    Dec 18, 2015
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    Thank you Tracecom. I'll give the relay a try tomorrow and let you know how it goes.
     
  11. tracecom

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  12. MyTPioneer

    Thread Starter New Member

    Dec 18, 2015
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    I went with a SPST - 5VDC Reed Relay from Radio Shack that I had laying around and it is working like a charm.

    Thanks a ton for the suggestion and guidance Tracecom.
     
  13. Tonyr1084

    Active Member

    Sep 24, 2015
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    Good circuit - and possibly more reliable than a 5VDC Reed switch relay. But if you use the electronic form I'd recommend a snubber diode across the motor with the anode toward the supply. But if you're using the reed switch then you don't need the diode, there's no electronics to be harmed.

    [edit] - If you're using a relay then I'm hoping you have a snubber diode across the relay to prevent flyback from damaging your controlling source.
     
  14. MyTPioneer

    Thread Starter New Member

    Dec 18, 2015
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    @Tonyr1084 - What you're recommending makes sense. I have no diode at the moment, but I'll be sure to add one. Thank you for the advice.
     
  15. crutschow

    Expert

    Mar 14, 2008
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    Not generally true.
    Relay contacts (especially the small contacts on a reed relay) may also need a snubber diode when driving an inductive/motor load to prevent contact burning and welding (since without a snubber the inductive energy will be dissipated in an arc across the contacts as they open).
     
  16. Tonyr1084

    Active Member

    Sep 24, 2015
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    Good point. I sort of forgot about that.
     
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