Conveyor belt with gantry

You can use this model with my rail trolley. But for better interaction with touch sensor you should add bumper between frame and black axle.

For this purpose, I created instruction, you can see on the right. For bigger version -- click on it.

Remember that motor connected to Port A support the direction of movement of the conveyor belt.

Changing the direction of the motor connected to port B is forced alternately by activating the touch sensor.

EV3 Brick assigned ports:
  :: Port 1 for ultrasonic sensor
  :: Port 2 for touch sensor
  :: Port 3 for touch sensor
  :: Port A for medium motor
  :: Port B for medium motor

Digital Model  ||  LeJOS Program Source  ||  LeJOS Executable File
Building Instruction -- Gantry  ||  Building Instruction -- Conveyor Belt

Self-ropelled Rail Trolley

This machine is dedicated to, move on toothed bar or elements with rack, like this one:

  Toothed Bar

  Gear Rack

The base element, that everything is building on is Technic Liftarm 5 x 11 Open Center Frame Thick. 

Thanks to the size of  used micromotor; I can build more lighter model and have more free space inside the frame.

Digital Model || Building Instruction