Assembly Line Automation

Discussion in 'The Projects Forum' started by ronbowalker, Mar 9, 2010.

  1. ronbowalker

    Thread Starter Member

    Jun 26, 2009
    23
    0
    Task at hand:
    I am trying to drop an electronic pin thru a tube and into a hole on a board, and then move to the next hole for the next pin.

    List of Components:
    Pin size = 1/6" dia x 1/4" length.
    PIC16F819 MicroController.
    5vdc power.
    5vdc step motors.
    LCD serial display to count the pins already dropped.

    1. Optic Interrupter to detect the dropped pin...recommendations?
    2. Output to Microcontroller/s will be ?
    3. Microcontroller/s will detect and trigger motors how?
    4. Serial LCS display to be achieved how?

    Programming stepper motors is already done, but I am using a manual button to signal "drop" completions on the microcontroller. It's the rest that I am in need of help with...and I figure it will require 2 microcontrollers to be doing two things at the same time.

    Any help in getting this to the drawing board would be greatly appreciated.
     
  2. ronbowalker

    Thread Starter Member

    Jun 26, 2009
    23
    0
    This is true Alberto....but I was hoping to verify the pin actually dropped without error to assure the feed line did not have any voids or spaces in it. That is why I was going to use an Interrupter to verify the pin drop.

    Your input is appreciated, and further assistance would be greatly appreciated.

    I will roll your idea around in my head a bit also to see if it would be error proof.
     
  3. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    Is there a way you can "shine" some light from under the board?? If so, then you may be able to come up with a cylinder type dispenser with 2 tubes on it, that can pivot a few degrees from each other, what you can do is have a photodetector in one tube to detect the light coming through the hole, and then have it pivot and dispense a pin, then it can pivot back and check to see if light is still shining through, if it is, a pin is not there, is light is blocked then pin has successfully been placed in hole, (or your light source went out ;))....

    PIN DROPPER TUBE.jpg

    you wouldn't have to modify the X or Y axis travel to compensate for the 2 tubes, if both are in the same distance from center and pivot from the center of the "barrel", you can have one tube default as the "center" of your X and Y axis...

    B. Morse
     
  4. ronbowalker

    Thread Starter Member

    Jun 26, 2009
    23
    0
    All good ideas.
    The pins are set on a rail by another pin organizer/sorter from a bulk bin then pushed along the rail to the "drop" point by a "pusher". Occasionally back peddling on the rail to fetch another dropped load of pins the "pusher" then racks the pins up and is ready for continuous feed to the "drop" point. So an interrupter verifying the drop will help verify all is going fine from start to end. Dropping 37 pins without a hitch is the idea I am looking for. And then moving a new plate into place and prep another 37 pins for the drops.

    I have never done an interupter and I am not sure how output from an interrupter will become an input on the microcontroller. I am also not familiar with how fast and accurate an Interrupter device is and whetheer it will work on free falling pins or not. Learning curve and patience on this end is already figured into my project so all ideas are good ideas to me right now. Any idea as to Interrupters to use?
     
  5. ronbowalker

    Thread Starter Member

    Jun 26, 2009
    23
    0
    I can direct the light upward/vertical thru the hole and a dropped pin will then block the line of sight when it lands in the plate. This does create a solid signature/verification of a dropped pin. This might be better than a speeding pin free falling thru a tube this small. and when the plate or tube is reset to the next hole, it will re-establish the line of sight. This in turn would verify a good "drop" co-ordinate has been achieved in the repositioning. Interesting.....
     
  6. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    These are the typical circuits I would use with 5 volt TTL logic. These are good for directly interfacing to a microcontroller also (given it is 5 volt or the microcontroller has 5 volt tolerant inputs...)..


    This would be an emitter detector pair......the output would go low when led source is blocked... high when clear.
    [​IMG]

    This one would be good for the rotating drum dispenser with just the photodetector / phototransistor...(and light shining from under the board as trigger source.) Output would be normally low, will turn high when IR light is detected.

    [​IMG]


    There are also so many different types and configurations for IR detectors/Photodiodes/Phototransistors, etc....

    Take your pick...;)
    [​IMG]

    I would go for a simple photodiode ( like the one in the picture, bottom right, looks like a black LED).... would be easy to implement, just have to drill a 3/16" hole for it to fit right in, and if you countersink the Photodiode, and drill a pass through hole about the same diameter of the pins, then you can get a much more "accurate" positioning and pin detection...

    Pin Dispenser Diode Setup.jpg

    B. Morse
    B. Morse
     
    Last edited: Mar 10, 2010
  7. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    Here is a simple sketch of the actuation of the cylinder... should not have to move that far only enough to clear the distance between center of holes.... so the "pulling" rod can be actuated with a spring return solenoid (that way the solenoid only has to be energized when dispensing a pin, since you are spending more time using the photodetector, when checking the hole, before dropping a pin and then checking it again once the pin drops, then have to look for next hole), I would make that the "default state" when the solenoid is off).

    The length of the stroke should be equal to the arc length between hole centers...

    Pin Dispenser Diode Rotation.jpg

    B. Morse
     
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