Delta robot (flex picker) for Lego World 2017

A completely new delta robot has been build for Lego World 2017. The robot is based on the ABB FlexPicker Robot. You can read more about building the Lego Version at Eurobricks.

More photos are available at our Flickr page: and videos are available at Youtube:

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Loading the train with the 6-axis DOF robot arm

I wrote a small test program for the robot arm to load the train with two containers. Loading the two wagons was done in one minute, so much faster than the candy crane.

Have a look at the video and please share with me what you think of it.

Engineering the new delivery station for Lego World 2016

For Lego World 2016, we are engineering a new delivery station. Some background information: in the 2015 version, the candy crane grabbed the candy directly. Unfortunately, too often the candy fell out of the grabber during the movement of the crane. Therefore, we decided to update the crane that it would pick up the complete container (with the candy, of course :-)). The crane update is already finished as you can read in our previous article. In this article, you can read about the ideas of the new delivery station.

Sketch Delivery Station for Lego World 2016

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A new video has been uploaded: candy crane version 2016

A new video has been uploaded to our Youtube channel about the candy crane version 2016:

  • Improved grabber
  • More robust look
  • Power chains


Building a power chain system (for the candy crane)

When building the candy crane, I was able to test it without using the power transformer (art 45517). At Lego World, because of the power consumption, it was needed that we hooked up both EV’3 to a power transformer. The cables of the transformer sometimes got into the running wheels, causing the system to fail. So, we needed to add a power chain system like this:

Power Chain System

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Updated crane hoist positioning

As described in the previous post (“Plans for Lego World 2016”), the updated crane uses two touch sensors for the positioning of the hoist. In  this article, I explain this in more detail.

Sioux.NET on Track - Candy Crane - Hoist

The two sensors slide over two rails that makes sure that they are pressed or released. By this means, we can distinguish four positions that are shown in the picture below:

Sioux.NET on Track - Positioning Hoist system

The numbers 1 to 3 are ‘defined’ positions:
1. Pickup position where the container is picked up from the conveyor belt.
2. Loading position #1 where the container is loaded into the train at track 1
3. Same as previous, but then for track 2.

Position 4 defines ‘the rest’, that is any position between the defined numbers and left from position 3. But note that there is no position 4 at the right from position 1. This is important for determining the starting position: when starting up the EV3 of the hoist, the EV3 can determine if it is on position 1, 2, 3 or 4 based on the state of the two touch sensors. In case of position 4, it is not exactly defined. But one thing is certain: if the hoist moves to the right, it will eventually find position 1. That is the reason that there is no position 4 at the right of position 1. Otherwise we wouldn’t know at startup in what direction the hoist should move to one of the defined positions.

So, the first thing to do when starting up: move the hoist to position 1 by moving to the right until it finds that sensor 1 is pressed and sensor 2 is released. From that moment, it is easy: if the hoist has to move to one of the three defined locations:

  1. if the new position > current position: move to the left
  2. if the new position < current position: move to the right.

And keep on moving, until the touch sensors indicate that you have reached the desired position:

  1. Touch sensor 1 = pressed  and Touch sensor 2 = released
  2. Touch sensor 1 = released  and Touch sensor 2 = pressed
  3. Touch sensor 1 = released and Touch sensor 2 = released

A demo program that randomly chooses the new position, has proven that the touch sensor readings are very accurate and that it never failed to miss a location. If you are interested in the EV3 program, please drop me a note.

Plans for Lego World 2016


Light Bulb

The Sioux.NET on Track team has made new plans for the layout that will be demonstrated at Lego World Utrecht in 2016. In this article, you’ll find a summary of these plans. Stay tuned this year for some nice buildings and of course, lots of programming!

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