random motor controller

Discussion in 'The Projects Forum' started by sparky30_06, Apr 15, 2012.

  1. sparky30_06

    Thread Starter New Member

    Apr 15, 2012
    3
    0
    Hello everyone, I'm hoping you guys can help me out on a small project I am trying to build.

    I have a turn table that is powered by a 12V DC motor.

    I would like to build a circuit that would randomize the direct and also the run and stop time for the motor.

    I would like the run time to be varied from 0 seconds to 30 seconds, the stop time to be 1 to 5 seconds, and that also to be a random variable that is always changing, and would like to be able to change the random duration.

    so basically I would like the table to run forward direction for 0 to 30 seconds (random and different each time), then stop for 1 to 5 seconds(random and different each time), then when it restarts it could run forward or backwards. everything being random.

    Motor direction will be controled with realys so the circuit will only have to handle energizing the coils of the ice cubes.

    This all has to run off 12volts DC

    If anyone has seen the cat laser towers that spin around randomly that is kind of what I'm looking for but I need a pause between direction change due to turning mass on the table

    Thanks guys,
    Sparky
     
  2. KMoffett

    AAC Fanatic!

    Dec 19, 2007
    2,574
    230
    Random...to quote my wife: "It's only complicated if you understand it!"

    1: It's very difficult to achieve true randomness.
    2. "random and different each time" is not random.
    3. Pseudo-random can be done with common electronics.
    4: Digital pseudo-random is implemented in discrete steps. How many different times do you want from 1-to-30 sec. and 1-to-5 sec?
    5: If you need to the stop the high-mass turntable in the 1-to-5 sec. interval, you will need to add a brake function.
    6: A small 8-pin microcontroller programmed in BASIC would be my choice of timing control, followed by two SPDT relays, and a brake resistor.

    Just thinking out loud.

    Ken
     
  3. praondevou

    AAC Fanatic!

    Jul 9, 2011
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  4. sparky30_06

    Thread Starter New Member

    Apr 15, 2012
    3
    0
    Actually with the gear reduction and chain reduction the table stops turning in under a second when de energized so a braking circuit is not needed.
     
  5. Felo

    Member

    Feb 20, 2012
    91
    13
    Do you have any experience with microcontrollers? or at least do you feel comfortable with them?
     
  6. sparky30_06

    Thread Starter New Member

    Apr 15, 2012
    3
    0
    Never worked with them but always willing to learn and try. what's the worst that can happen?? I let the magic smoke out of it and start over??
     
  7. KMoffett

    AAC Fanatic!

    Dec 19, 2007
    2,574
    230
    Then I would suggest a PICAXE. http://www.picaxe.com/
    They are relatively cheap, ~$3.50 for an 8-pin IC. The BASIC programming editing software and manuals are free. It only takes 2 resistors and a home-brew serial cable to program. They have a very helpful, moderated forum. These were originally designed for schools so "Are you smarter than a 5th grader!" ;)

    Ken
     
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