Lego Mindstorms FLL Robot

Hi! My name is Aaed Musa I am 16 years old, in the 10th grade, and I am a volunteer coach for the FLL team master builders at Shiva robotics academy. In this instructables I will i will shows how Me and my kids built a FLL robot for the 2019 FLL city Shaper competition. Although this is specifically for the 2019 competition this can be used for any year of FLL tournaments as well for personal use and teaching students about lego robotics. This is a great resource for both students, teachers and parents, and even people eho just have interest in lego's. Lets get started!!

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Step 1: Supplies

If you wish to follow this project the same way I have you will need

  • A Lego mindstoms kit that can be bought here

From the Kit I used the following

  • 3 large motors
  • 1 medium motor
  • 2 touch sensors
  • 1 color sensor
  • 1 gyro sensor

Other material

  • Lego gear racks that can be bought here
  • A laptop with the ev3 software which can be downloaded here
  • A FLL city shaper Mat
  • Lots of patience and commitment

Step 2: Building the Robot/ and Robot Design

Our robot was made with many different alterations. We did not follow any exact steps in making it. here are pictures of the robot, try and recreate it as best as possible.Our robot has undergone many changes, we initially had 2 robots and decided to consolidate it into 1 because of problems with different programs being on each. Then we changed it to a sort of box like robot but the motor attachments did not fit well, finally we changed to the current version we have now which has 2 very important mechanisms. The first is the elevator mechanism and the second it the arm mechanism. Here are some details of each as well as detail of what was used.


The elevator mechanism which is permanently attached to the robot was added because it can be used with many attachments efficiently. The elevator allows attachments to move up and down which is the most important thing for these types of missions. The elevator mission, the crane mission, the tree mission, and the traffic mission all need attachments that can move up and down. An elevator seemed like the best idea because anything can be attached to it making it able to move up and down. The other benefit with the elevator is that it allows minimal attachments, because it moves in a linear fashion it can then have the same attachment for multiple missions. the elevator was simply made by using Lego gear racks and gears as well as 1 large Lego motor to turn it. Some of the uses of the elevator include moving objects up and down, hitting an object and moving the attachment up so it is out the way, and pushing a mission upwards.


The arm mechanism utilizes a medium motor and 2 black Lego gears to move the arm up and down in a circular motion. This is very useful for hitting thing and retracting the arm. most Importantly it is used to assist the elevator mechanism by fully lifting an object. for example in the traffic mission the elevator lifts the mechanism a little, and them the arm fully lifts it. The arm allows things to be done faster as well ass a retractable piece that folds in. The design of this was made by the kids and was very smart because it saved us from having too many attachments.


2 large motors are used for the wheels and steering while 1 of them is used for the elevator mechanism. 1 medium motor is used for the arm mechanism.

Step 3: Attatchments

So far we have used 5 attachments for the 2019 competition but that can and will change depending on the efficiency of them and our ability to complete missions.

List of attachments

  • A flat panel for pushing the blocks
  • 2 angled mechanisms for the crane mission
  • A long rod piece for the elevator mission
  • a holder for the tree mission

The next steps will go in depth for each of the attachments

Step 4: Block Attachment

the block pushing attachment is literally just a flat panel used to push the blocks. its very simple and uses 6 green panels and 1 slim grey one.

Step 5: The JIG

The jig we used is 2 panels long and 3 panels wide. It used to align the robot so it goes straight.

Step 6: Traffic Attachment

this is both the traffic and crane attachment which is used to lift the traffic and push it up against the wall.

Step 7: Elevator

The elevator attachment is simple just a rod the is connected to the elevator so it hits it and goes back up.

Step 8: Program

the program is the very important, I have made our ev3 files available with the swing program, gyro program, line follower, and reset.

Step 9: Gyro

The gyro sensor was used to make sure the robot didn't drift of course. It checks to see its angle and it corrects it based on the angle. The gyro code is also available in the files listed under step 8.

Step 10: Robot Reset

In the beginning of each program the robot has to reset so that it knows its position else it will mess up. It basically resets all the mechanisms, sensors and rotations of motors.

Step 11: Line Follower

here is a video of 2 of our flawless line follower program. 1 is the earlier design while the other is the new design ,It really captures our entire project.

Step 12: Conclusion

Thank you for viewing this instructable, the best advice I can give if you are attempting to build a robot is to keep trying and watch many YouTube videos. if you have any questions please email me at I am glad t answer any lingering questions.

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