Rubber Band Attachment for loops pushed to the border - FLL2012 Medicine Pro Preview

Enchansing a previous attachment, but only this time we are solving the FIRST LEGO League 2012 Medicine mission. There is a lever and a rubber band. When the lever is released the rubber band activates the attachment. 

  • #101
  • 16 Aug 2015
  • 4:23

The FIRST LEGO League 2012Senior Solutions, Medicine mission involves a loop. Only the green loop must be taken, but the position of the green loop is random at the beginning of the round. This means the robot construction should use a color/ligth sensor and should also collect the loop with an attachment and return it back to base. This mission was quite near the base and it is very elegant to solve it without the use of a motor so that the motor is free for other missions.  

Check out the video and leave a comment if you have any questions or suggestions for new videos.

Previous videos on rubber bands:

  1. Rubber bands - Solving the FIRST LEGO League World Class COMMUNITY TREE
  2. Rubber bands - LEGO robot attachment that triggers with a motor
  3. Rubber bands - LEGO robot attachment triggered with a motor - part 2 removing the motor
  4. Rubber bands - one more way to remove the LEGO attachment dependency on the motor for triggering
  5. Rubber bands pinless attachment for taking loops
  6. Rubber bands attachment for circular motion - solving FLL 2012 stove 

Other pinless attachments:

  1. Quick Pinless Attachments for LEGO EV3 Competition Robots (Part 1)
  2. Quick Pinless Attachments for LEGO EV3 Competition Robots (Part 2)


- In this video, we continue building attachments with rubber bands and we are improving an attachment from a previous video to make it work for a little bit different loop like this. We can have an attachment for this loop, that was stationary on the field. From the Senior Solutions 2012 competition, we had the medicine and we'll build an attachment for solving the medicine.

The mission is like this. We have two...three... I think there were four medicines and they were all different color. So, the robot move to the medicines and depending on the color, it must collect only the one with the specific color. It might be green or orange or other colors and that's the competition. Again, in order to solve and to collect the medicine and return it back to base, we are using an attachment that it's still with the rubber band. This here was an attachment, we showed it in a previous video and we did a little modification. For example, we made this axle here a little bit longer so that we can collect loops that are taller than the yellow. As you can see, the green medicine is taller than this loop. And another modification, is that this medicine, it was placed on the field. It was very difficult to reach this medicine and push it because when you are pushing it, it moves with the attachment and that was one of the problems. This here is the border of the field and the medicine is placed like this. The only way that you can actually collect these medicines with this attachment is to push this medicine to the border. And when it push to the border, we will activate the attachment. The problem is that with this axle, at the front of the attachment. Alright, here, when you're pushing the medicine, you can't push it in different directions so it's not very accurate. A simple solution is to add a gear wheel at the front of the attachment and now, when you are pushing the medicine,

it is always more precise. Now, add the rubber band, then I load the attachment and now, we program the robot again, it is a pin-less attachment. We place the robot over the attachment just like this very easily. We program the robot, it moves on the field then it somehow reaches the medicine and then it pushes. The medicine moves with the robot and when we reach the border of the field, the whole attachment is activated and we can return back to base with the loop.

This and other attachments are from an idea from the theme brother in arms, they were participating in a competition and actually solving the missions this way. If you have ideas for other attachments, share the below in the comments and you can find instructions for building this, in the material sections below the video. The robot is from episode 58. It's the modified version of Mike.