User a Pot to read Deg of rotation.

Discussion in 'General Electronics Chat' started by mazur50, Jun 7, 2007.

  1. mazur50

    Thread Starter Member

    Feb 5, 2007
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    I am looking for a circuit. that when i turn a pot it will tell me how many deg of rotaion i have turned. thanks.

    Mike
     
  2. cumesoftware

    Senior Member

    Apr 27, 2007
    1,330
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    Pots are not very reliable for that. You can use rotation sensors for that.
     
  3. mazur50

    Thread Starter Member

    Feb 5, 2007
    28
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    Would you have anytip to lead me in that direction of the rotation sensor and a circuit.
     
  4. cumesoftware

    Senior Member

    Apr 27, 2007
    1,330
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    I will see.
     
  5. Tube Tech

    Active Member

    Jan 11, 2007
    46
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    2 paths to rotation sensing:

    gear wheel and a hall effect sensor. limited resolution.

    optical marks and optical sensing. as much resolution as you can afford.
     
  6. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Or you can find a servo pot with no stop.
     
  7. mazur50

    Thread Starter Member

    Feb 5, 2007
    28
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    I only need like 90 of sencing. I am tring to make a device so i can tell howmuch timming a armature has with out using a protractor.
     
  8. lightingman

    Senior Member

    Apr 19, 2007
    374
    22
    Hi....The most acurate way is to use an optical shaft encoder..... These are quite expensive, but I have bought some on e-bay before at around 20 GBP.You would need a counter to count the pulses, and if you need to detect direction, a JK flip-flop.....Daniel.
     
  9. cumesoftware

    Senior Member

    Apr 27, 2007
    1,330
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    I think that was the answer I was looking for.
     
  10. mrmeval

    Distinguished Member

    Jun 30, 2006
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  11. mazur50

    Thread Starter Member

    Feb 5, 2007
    28
    0
    does anyone know where to get servo pots i have been looking but cant find them
     
  12. mazur50

    Thread Starter Member

    Feb 5, 2007
    28
    0
  13. cumesoftware

    Senior Member

    Apr 27, 2007
    1,330
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    For the first three, yes.
     
  14. mazur50

    Thread Starter Member

    Feb 5, 2007
    28
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    Yes to what question.
     
  15. cumesoftware

    Senior Member

    Apr 27, 2007
    1,330
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    Yes, for the first two options (first three links) described above, you might need a microcontroller. For the last one, maybe, maybe not.
     
  16. kender

    Senior Member

    Jan 17, 2007
    263
    0
    The circuit is very simple: connect the bottom of the pot to the power supply, bottom to ground. You will get a retiomatric sensor i.e. the ration of the voltage on the wiper to the power supply voltage will be proportional to the angle. Your problem is more mechanical rather than electrical: how are you going to secure the pot to the moving parts?
     
  17. Uman

    Member

    May 2, 2004
    11
    0
    Typically a precision pot is used when angles are less than 270 degrees and angle encoders when greater than 270 degrees. Precision pot are much cheaper than encoders and less components involved.
    We have used precision pots for turrent steering position feedback on large vehicles with indepentent turrent bogies quite successfully.
     
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