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    Brick Mixer

     Brick Mixer 

    Since the first version of my card reader, I intend to use it to program the order of brickes in a "brick mixer", taking bricks of different colors and outputting an ordered flow of bricks. I wondered for a while how to achieve this using only three motors... but finally succeeded, two of the motors performing two actions.

    The brick mixer has four main parts:

      • The brick feeder, that supplies 4 kind of colored bricks
      • The card reader, which determines the order of the bricks in the output flow
      • The conveyor belt that outputs the bricks streams
      • The picker arm, that takes bricks in the right chute of the feeder and place them on the conveyor

    Since the conveyor and the card reader uses one way motion, I used a differential and two ratchets to power the card reader when the motor turns forward and the conveyor when it turns backward. The micromotor of the picker drives the grip through a fast acting rubber belt, which slips while the micromotor goes on driving the gears to lower/lift the grip.

    The carriage of the picker is guided by the front rail, and pins in that rail define stops position (one in front of each chute + on in front of the conveyor) detected by a touch sensor. In order to have a fast motion and good precision, the carriage goes past the pin because of inertia, then comes back on the pin. The pin of the conveyor is bigger so that the dropped brick is well centered.

    Coding the card

    With the color order of my brick mixer, each color is coded (in binary) as follow:

        00 = Red brick (chute nearest of the conveyor)
        01 = Gray brick
        10 = Black brick
        11 = Yellow brick (chute furthest of the conveyor)

    Since the card reader reads a 15 bits word, I used the 14 lower bits to encode the color of 7 bricks, while the 15th bit is a "continue" bit: when the card contains 0 in this bit, the brick mixer stops after placing the 7th brick. If its value is 1, the brick mixer asks for another card, reads it and stores 7 other bricks. The first brick is coded as the 2 least significant bits. Example:

    Order

    Continue

    7th brick

    6th brick

    5th brick

    4th brick

    3rd brick

    2nd brick

    1st brick

    To code

    No

    Yellow

    Black

    Yellow

    Gray

    Yellow

    Red

    Yellow

    Bin. value

    0

    11

    10

    11

    01

    11

    00

    11

    Hex value

    3

    B

    7

    3

    Dec. value

    15219

    Plug in this value in the Card Reader 2 basic program to obtain the plates colors of the card: B Y G Y G B G Y B G Y G B Y G Y

     


    Brick Mixer (800k) 


    Pick brick (130K) 


    Drop brick (90K)

     

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LEGO® MINDSTORMS® and Technic®MINDSTORMS® EV3/NXTMINDSTORMS SensorsLEGO® technical dataLDrawMiscellaneous LEGO®LEGO® & PhotographyPanoramic PhotographyPhoto GalleryHome