Atari joystick motor/servo control

Discussion in 'The Projects Forum' started by Andy Hayes, Oct 8, 2013.

  1. Andy Hayes

    Thread Starter New Member

    Oct 8, 2013
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    Hi all, just registered here and this is my first post....

    I have an old Atari 2600 joystick, and i would like to know if there is a way i could hook it up to control a motor - i came across this thread: http://forum.allaboutcircuits.com/showthread.php?t=27543

    But, not sure if the poster was referring to the normal atari 2600 or the wireless one with the 9v battery option,want to know how to mod the joystick as to power it from an alternate power source..Looking for some clarification of the solutions outlined in the thread, i want to control a small toy motor or servo with the joystick...
     
  2. elec_mech

    Senior Member

    Nov 12, 2008
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    Welcome to AAC.

    Take a look here, here, and here for pinout information on an Atari 2600 joystick controller. In essence, it contains 5 normally open (N.O.) switches - up, down, left, right for the joystick and one additional 'fire' button on the base. It appears you can close two of the joystick switches at the same time, e.g., up and right if you move the joystick in that direction, so keep that in mind.

    I'm not sure what the current rating of the switches are, but if you just want to turn a toy motor powered by batteries on or off, you can probably connect it directly to the controller. It appears you can use a DB9 connector if you don't want to cut the end of the controller cord off.

    Note that you'll only be able to turn the motor on or off, not control speed. If you want to reverse direction, you can probably get away with a DPDT relay or two to reverse the polarity of power going to the motor.

    Let us know exactly how you want to control the motor with the controller and we can provide more information. Good luck.
     
  3. Andy Hayes

    Thread Starter New Member

    Oct 8, 2013
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    Thanks for such a swift reply:)

    I would like to simply have a toy doll's arms connected to the base of a motor on either side - the dolls arms detatch so i will place the motors inside the body so they stick out the arm sockets and attach the arms onto the axle of the motor. All i want to happen is the arms to rotate left and right in a circular motion respectively when i press left or right on the joystick :)

    Its very simple, i just want to clarify a few things,how relays can work in relation to motor control via the joystick was the main issue, i understand how most components work but am new to aspects of motor control in project design.
     
  4. elec_mech

    Senior Member

    Nov 12, 2008
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    Hmm, a standard hobby motor with no gearing is going to spin crazy fast and may not have enough torque to spin the arms. Both can be solved by adding a gearbox, but I don't know how much room is inside the doll. And even with a gearbox, the arms are probably still going to spin quite fast. Perhaps adding PWM to the mix would take of the speed, but now the project is going to be big and a bit complex.

    A servo might be a better option - it will be slower and won't require a gearbox. It will require a servo signal, but this is relatively easy to accomplish with a 555.

    So, if looking at the side of the doll, the arms will spin clockwise or counter-clockwise, correct?

    When the arms spin, are they supposed to spin in the same direction or opposite one another? If the former, you may be able to put the arms on an axle or rod and use just one motor or servo to spin them.

    The big question at this point is do you want to use a motor or a servo? Each will require its own unique control scheme. If you have some handy to play with, I suggest mounting the arms to them and spinning to see if the motor/servo is able to spin the arms at the desired speed.
     
  5. Andy Hayes

    Thread Starter New Member

    Oct 8, 2013
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    The arms are very lightweight ,and ,yes i want them to spin in the same direction so both on an axle might be an option..

    Speedwise - i may actually want the arms to rotate superfast(!)..But, if i decide i'm after something slower and was to add a gearbox, could you link me to what i would need? I have no idea here on what i would be looking for...
    Never used PWM but imagine that would be achievable with a 555 setup?

    I have motors at ready, but no servo's as of yet, will be messing around with this over the weekend i think....
     
  6. elec_mech

    Senior Member

    Nov 12, 2008
    1,513
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    As I'm inherently lazy, I like to use pre-made gearboxes when possible. Take a look here. These are easy to assemble and you can quickly switch the gears until you get the RPM that works best for your application. This should be fairly simple to implement with the Atari controller.

    Of course, if you want to use your own motors and vary the speed on the fly, you can use PWM. I haven't used PWM yet myself, but I'm pretty sure I've come across some 555 PWM circuits I can find again.
     
  7. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    I would strongly recommend elec_mech's idea. Without some sort of gearing, at best the arms would be a blur; I wouldn't be surprised if they either flew off or damaged the motor. I've used these gearings in haunted props for Halloween.
     
  8. Andy Hayes

    Thread Starter New Member

    Oct 8, 2013
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    Thanks Guys, will let you know how i get on after the weekend!
     
  9. Andy Hayes

    Thread Starter New Member

    Oct 8, 2013
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    [​IMG]

    Ok, i tested out the speed of the toy motor with the arm and it actually rotates at a speed i want(!) (Yep, will reveal all once i get a few things straight)....How do i wire up the atari joystick to control the motor, could anyone make me a simple diagram. Would be very grateful if someone could... :) I know the brown and green wire are left and right but just want to clarify best way to go about wiring things up...
     
  10. elec_mech

    Senior Member

    Nov 12, 2008
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    Simple is a relative term, but I think I've got it. To turn the motor on and change the direction with a single button press (moving the joystick left or right), you'll need two SPDT or DPDT relays. I've attached a drawing.




    Note the following:
    • If two lines cross each other, they are not connected unless there is a dot over the intersection.
    • Since you are using three batteries (4.5V), you should look for relays with coils rated for 5VDC. The ratings of the contacts won't matter much since anything you select should work for your motor.
    • You can use a DB9 plug to connect to the Atari connector if you don't want to modify the controller's innards.
    Let us know if you have any questions.
     
  11. Andy Hayes

    Thread Starter New Member

    Oct 8, 2013
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    Thanks ever so much! I'll let you know how i get on soon :)
     
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