Servo control

Discussion in 'The Projects Forum' started by RtnlSltn, Oct 4, 2006.

  1. RtnlSltn

    Thread Starter New Member

    Oct 4, 2006
    0
    0
    Hi, I'm new here. I stumbled across this site after searching for a solution to my problem. My name is Justin and I make custom computers. I won't bore you with everything, but here is what I have to do.

    I need to flick a switch, or something related, that causes a servo to move to about 90*. When i flick the switch the opposite direction, i need it to reverse 90*. In both situations i need the servo to turn itself off so it does not drain power. I have purchased a large assortment of switches from RadioShack including feeler, toggle, and pot. I was thinking of having the servo hit the feeler switch as it hit my desired angle to turn it off, but then i wouldnt be able to have the servo reverse unless i had a reverse polarity switch of some sort?

    I don't know, I'm decent with electronics, but this stuff goes above me. Any help would be awesome! I'd be glad to help anyone with computer problems in return.


    Thanks,

    Justin
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    Need somew more info before we can help. How big a motor? Ac or DC? How fast does it need to go?
     
  3. RtnlSltn

    Thread Starter New Member

    Oct 4, 2006
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    0
    It has to run off of a computer power supply. The speed does not really matter, but preferably it opens as fast as a servo spins.

    Basically it needs to open a door 90* when i turn the switch to "on", as well as turn a fan on. When i hit the switch to "off" it needs to turn -90* to its original position and turn the fan off. In either situation it shouldnt be consuming power more than what it needs to shut the door, basically it needs a timer. A timer would have the servo on for X amount of seconds, then when its closed or open, it turns off. I really do not care which way this has to be done, however the smaller the better. I'm open to anything.
     
  4. sci-3d

    Well-Known Member

    Aug 22, 2006
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    0
  5. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    Still nothing to work with. How big is the door? What kind of mass? How fast is the servo going to spin?
     
  6. pebe

    AAC Fanatic!

    Oct 11, 2004
    628
    3
    Here’s a fairly simple solution. It would be easier if the PC power supply had dual polarity supply of equal voltages and powers. But as it hasn’t this circuit uses a relay to change polarity as required.

    M is the servo motor and F is the fan. S1 switches power to the relay coil. And operates the changeover contacts S4 and S5. S2 and S3 are limit switches that are normally closed when the motor is running.

    When S1 is open the relay is de-energised. S4 and S5 will be in the positions shown. S2 limit switch will be closed and S3 switch will be open. Motor and fan have no supply.

    When S1 is switched on the servo motor will run until the limit switch S2 opens. The fan will stay on.
     
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