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Lego Colour Ball Sorting Robot ArmRobot-App Page

Relevant Robots:
  • LEGO - Mindstorms NXT 1.0
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Robot App™ Description

Lego Colour Ball Sorting app.

First, I built a small addition to the main model, using the available third motor to which I attached a handle. I then connected it to the gate assembly motor, so that I could operate it by turning the handle, controlling the release of balls down the track. I set up a small test program to display the output of the colour sensor for each ball, and thus ascertained that blue gave output 2, green 3, yellow 4, red 5 and the white background (when no ball was present) 6.

I then started the main program.
My first attempt at the main program broke the problem into the following logical steps.
* return the rotating ball track to the zero, or parked position
* set the gate so that the upper rod is in the closed positon (after one run it will normally be there already)
* rotate the gate motor 180 degrees, allowing one ball to move under the sensor
* read the ball colour and enter a fiveway switch
* for colour numbers 2(blue) to 5(red), say the colour name and rotate the turntable motor no of rotations = colour number -1
* for colour number 6 (white), say Goodbye, rotate the turntable back to the parked position
* open the bottom gate rod by rotating the gate motor 180 degrees, which release the ball (if any), closing the upper gate rod
* wait 30 seconds to allow the ball to roll off the runway into the receptacle
* repeat the loop

Developer: Robin Newman

LEGO®is a trademark of the LEGO Group of companies which does not sponsor, authorize or endorse this app. This app does not feature any of LEGO's copyrighted or trademarked material, and is in accordance with their fair use guidelines.

Installation Instructions

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Robot App Requirements


LEGO Mindstorms software

LEGO Mindstorms NXT 2.0 kit parts #8547 and #9648 set, togeher with a turntable part 48452cx1
Other requirements:

1:30hrs. to build the robot.

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