EAGLE - Design digital in for a position sensor in a motor

Discussion in 'Digital Circuit Design' started by Rava, Dec 6, 2017 at 2:27 PM.

  1. Rava

    Thread Starter New Member

    Wednesday
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    I'm a new user to EAGLE and have an assignment to design a scheme for digital in (position sensor (Angle sensor?) for a motor). I would very much appreciate help, I don't know where to start. Thanks.
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    For DC/BLDC motors, this is typically done with a rotary encoder, two types are digital and quadrature, the latter requires initially using the one per rev reference mark to set a reference.
    If direction of motion is not important, it can also be done with a single output-multi pulse encoder with ref mark.
    If using a stepper motor, the encoder can be dispensed with and just a reference point initially used and from there the motor is stepped in 1.8° step resolution.
    Max.
     
  3. Rava

    Thread Starter New Member

    Wednesday
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    Thank you! I'm wondering where I can find these components to put them in EAGLE or are they already existing in the programe? If not, where do I find them?
     
  4. philba

    Active Member

    Aug 17, 2017
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    You might find a library part via a google search. But, I have found more complete crap library parts out there than good ones. Verify any part you find. A common problem is incorrect hole size, closely following by bad smd pad spacing. Don't trust, just verify.

    But, it's probably unlikely you will find a part so you should make your own. It's actually fairly easy to do. There are tutorials (google for eagle library tutorial). It's a 3 step process - design symbol, design package footprint, create device- connect symbol & package. I've been doing it for a while so I'm pretty fast but once you understand I expect you'd be reasonably quick. It takes me 10-15 minutes to create a simple 3-4 pin part. A 40-60 pin part might take a half hour. The largest amount of time is verifying that the right pins are connected to the right pads.

    Edit: by the way, be skeptical of data sheets, too. Get the physical part and "paper test" it before ordering a PCB. Print out the board on paper and see if it fits. I've been burned several times.
     
  5. MaxHeadRoom

    Expert

    Jul 18, 2013
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    A cheap version of the quadrature encoder that has a marker is the CUI AMT10 version at Digikey etc.
    If you want the output of the encoder, Google quadrature encoder.
    Max.
     
  6. Rava

    Thread Starter New Member

    Wednesday
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    Thank you! As I mentioned I'm very new to Eagle and don't really understand much of it. The only information I've been given is to design a scheme for a position sensor in a motor. How do I know how a position sensor looks like, if I were do design one?
     
  7. Rava

    Thread Starter New Member

    Wednesday
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    Thanks! I found it but how do i download it to Eagle?
     
  8. philba

    Active Member

    Aug 17, 2017
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    ebeowulf17 likes this.
  9. MaxHeadRoom

    Expert

    Jul 18, 2013
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    I assumed you had to integrate it as it is an external component to any Eagle scheme which is primarily a PCB/schematic capture program.
    To actually make one you need a three opto sensors, this is a crude one out there in schematic format, if you Google it the principle will come up in several places.
    Max.
    upload_2017-12-6_14-40-35.png
     
  10. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    AAC has a short explanation of a quadrature encoder, top of this page click EDUCATION
    - Vol. IV ,- Ch. 11, sequential circuits,- last entry. It lacks an index mark which would reset the D FF.
     
  11. ebeowulf17

    Well-Known Member

    Aug 12, 2014
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    That's true of parts in the included libraries too! I made a really embarrassing mistake in the only circuit board I ever produced with Eagle. I used its built in smt pads for what should've been standard, predictable, well known parts, but they were rotated and spaced wrong. Trust nothing.
     
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