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    SORT3R, an EV3 brick sorter

    As I have a long record of building color sorters... for RCX, NXT and now for EV3! SORT3R can be built with a single 31313 EV3 set. Well, almost! The kit contains a capable color sensor, but no colored elements to use with it... So for SORT3R I used ubiquitous 2x4 bricks, in 6 colors: black, blue, red, yellow, black and white. EV3 color sorter is also able to detect brown, but the EV3 kid doesn't contain enough parts to build a seventh bin (and the sensor is a bit less reliable on brown, sometimes confusing it with black). A bit improvement of EV3 color sensor over NXT one is that it is able to detect "nothing", SORT3R is thus able to detect that there is no more brick in the chute.

     

    Right side view.

    Left side view.

    SORT3R's back.

    The brick chute and sorting bins.

    SORT3R needs to be positioned very precisely on the chute to be able to work reliably. It is guided by the L2 beams on top of the bins structure that slide between the two rails on the robot.

    In the other direction the IR sensor reads (with excellent precision!) the position of the back of the white panel near the chute. The bins are wide enough so that positioning with rotation sensor only is enough to drop the bricks in the right place. The position is recalibrated before picking each new brick.

    The last bit needed to achieve pick up reliability was to compensate for the position of the brick itself that tended to slide a bit laterally at the end of the chute. The two wheels on sides of the arms put it gently back in place...

     

    Improving SORT3R reliability


    After testing a lot SORT3R, I discovered that sometimes it bumps into the chute when bringing a brick to sort bin. Indeed, the gripper arms come very close to the ramp, as shown on this image. If you have spare axlepins, the best solution is to flip the L beams on sides of color sensor. This gives a little more margin and avoids the problem.

    ...otherwise, just make sure that IR sensor assembly (and guiding rails) is not fully pushed in place.

    Video

     
    Link to YouTube video

    Building instructions

    SORT3R printable building instructions (PDF, 3.5 Mb).

    LDraw/MLCad MPD file.

    SORT3R sort bins printable building instructions (PDF, 2.7 Mb).

    LDraw/MLCad MPD file.

       

      SORT3R Connection Chart

      Device

      Port

      Touch sensor
      Color sensor
      IR sensor
      Head motor
      Drive motor
      Arm motor

      1
      3
      4
      A
      B
      C

     

    EV3 project

    SORT3R EV3 project with integrated building instructions (20Mb)

    SORT3R EV3 program only (70kb)

 

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