We are mentors, judges, teachers, professional engineers, and software developers with a lot of experience in FLL, and we've been helping teams for the last 15 years. At FLLCasts, we share specific courses, robot constructions, attachments, and programs demonstrating how various missions could be accomplished. Note that we do not share solutions for the current season as this is against our rules, but we share the principles by which various missions could be accomplished, and how similar missions were accomplished in the past. You have all the information in one place.
FLL is a journey that is sometimes difficult but always rewarding. You are not alone in this journey. FLLCasts has helped tens of thousands of students build Box Robots, use rubber bands, and program advanced state machines to achieve the consistency of the robot's behavior. We are your partner with all the experience and knowledge that we have, and we will guide you through the process of learning and accomplishing the missions.
That is where we hope this guide will take you in terms of programming. To know how to program robots consistently and reliably to reach a mission... more
That is where we hope this guide will take you in terms of robots and attachments - to know how to develop attachments that accomplish a mission... more
That is the current season of the competition, and you are reading this guide because you would like to prepare better for the robot game, have lots of fun, and advance to the next rounds.
The guide will help you with designing and using complex advanced attachments and will also help you with building reliable and consistent robots. But before any of this, you should get familiar with the season, its missions, and its rules.
Now that you’re familiar with the current season, it’s time to dive into a dedicated course tailored to your LEGO set. While you can participate in FLL using any LEGO set, the two most suitable options for building and programming your robot are the LEGO Education SPIKE Prime and the LEGO Mindstorms EV3. These sets offer the versatility, precision, and reliability needed to tackle the challenges of the competition.
If you don’t have a competition field from previous years, don’t worry — building alternative models and creating your own missions is a valuable and fun part of the learning process.
You can use these courses both during the season and in the off-season. Parents and teachers often encourage team members to work through them, tackle every mission, and achieve their goals. This combination — learning, practicing, and completing the missions — is the holy trinity of competition preparation.
During the season, move through them quickly to watch the tutorials and explore the content, using them as a reference when tackling your challenges. There’s usually not enough time to complete and submit solutions for every task, so focus on learning the approaches and strategies you can apply directly to your work.
This course introduces students to LEGO Education SPIKE Prime and includes a complete guide on building a wide range of attachments to tackle... more
Two fundamental concepts are essential for robotics competitions: ensuring the robot consistently navigates and positions itself accurately on the...
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Ready to dive deep into the 2024-2025 FIRST LEGO League SUBMERGED season? In this hands-on course, we showcase and explain a series of expertly...
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In this course, we demonstrate and explain example solutions for the FIRST LEGO League 2023-2024 MASTERPIECE competition using the MiniBox box...
moreBoth EV3 and NXT are no longer available for purchase from LEGO. While LEGO no longer sells these sets, nearly all constructions previously built with EV3 or NXT can still be reused. After all, they’re made from standard LEGO parts—the only difference lies in the electronics.
LEGO MINDSTORMS Robot Inventor is similar to SPIKE Prime. We've created a complete guide on how to use it to build all the different types of... more
EV3 was the set that took FLL to where it is today. We've built many resources for EV3, and starting with this course will give you a good idea of... more
NXT is long gone, but this was the first set we've used for FLL, and this was the construction we were using more
"Smart people learn from their mistakes. Wise people learn from everywhere they can."
When preparing for the current FLL season, nothing beats the value of experience gained from previous competitions. Unfortunately, that’s not always possible — after all, previous competitions are… well, in the past. You’re forming the team now, and it’s a brand-new group, which means the hands-on experience from past years is no longer there to draw on.
Luckily, we’ve been recording and explaining our solutions to FIRST LEGO League (FLL) challenges since 2012. We recommend starting with the most recent missions, then exploring older challenges, their solutions, and our reviews. By seeing how similar missions were approached in the past, you’ll build a powerful toolbox of knowledge. With these insights, you can choose which attachments and robots to adapt and modify for the current season.
Review, building instructions and tips and tricks for the season
Review, building instructions and tips and tricks for the season
Review, building instructions and tips and tricks for the season
Review, building instructions and tips and tricks for the season
Review, building instructions and tips and tricks for the season
Review, building instructions and tips and tricks for the season
Review, building instructions and tips and tricks for the season
We aim to build robots that can complete missions successfully 10 out of 10 times. Learning to design and program a reusable, consistent, and reliable robot is the single most valuable skill you can develop. Explore our “10 out of 10” tutorials to see real examples of robots built for maximum precision and repeatability.
To participate successfully in FIRST LEGO League competitions, it’s helpful to have a few additional parts. These extra pieces make it possible to build attachments and robots capable of accomplishing many more missions. The parts are readily available on the market — most commonly through BrickLink — and can be purchased easily. We’ve provided a recommended list and quantities, but you’re free to adjust and buy more or fewer parts based on your team’s needs.
When preparing for the competition, you’ll need to decide: Which robot should we build? There are many options for robot chassis designs and construction approaches. Review ideas from previous competitions and explore multiple robot constructions before choosing the design that best suits your team’s goals.
A well-built robot — whether simple or more complex — can perform strongly in local and regional events. Look at robots you can build from your LEGO set, but also take inspiration from other sets, as they often include clever features you can adapt. Consider factors like size, number of motors, sensors, and the ease of adding attachments. Your goal is to create a reusable, consistent, and competition-ready robot that matches your team’s capabilities and available parts.
Box Robots have become the most popular robot design in FIRST LEGO League, and for good reason. Built with a rectangular, enclosed frame, they make it easy to attach tools and mechanisms in a standardized way. This uniform attachment system speeds up mission runs, improves consistency, and allows teams to swap attachments quickly without redesigning the robot.
Their balanced frame and sturdy structure make Box Robots both stable and powerful, capable of handling a wide range of missions. While they may be a bit more challenging for rookie teams, the benefits far outweigh the learning curve. Some of the more advanced Box Robot designs may require additional LEGO parts beyond the standard set, but the added capability is often worth the investment.
We call them "X-Y Robots", and the concept is simple: a single large attachment at the front moves side-to-side along the X-axis and up-and-down along the Y-axis. This movement range allows the robot to interact with mission models in multiple directions without repositioning the base.
These are advanced robots — handle them with care. Their design flexibility is like providing a sharp knife: powerful in skilled hands, but risky if not used wisely. In fact, when X-Y Robots were first officially introduced, they almost disrupted the season, as many teams rushed to build one without fully understanding the complexity and trade-offs involved.
With the right expertise, X-Y Robots can be incredibly effective, and you can even adapt these constructions to work with your LEGO Education SPIKE Prime robot. Just be sure your team is ready for the challenge before committing to this design.
Here, you’ll find more LEGO Education SPIKE Prime robots to spark your creativity and inspire new ideas for your own builds.
With FLLCasts Tutorials, you can quickly find answers to your questions. Simply choose the most relevant video tutorial and press play. From mastering attachments to programming your robot for precise actions, you’ll find practical guidance on everything you need to succeed.
Learn to build effective attachments. Keep designs simple and avoid over-engineering; use as few parts as possible. Aim for quick-change, pinless attachments that can be swapped in seconds. A good attachment should work reliably at least 9 out of 10 times. Experiment with rubber bands, gear wheels, worm gears, racks, and levers to create versatile, efficient solutions.
Don’t limit yourself to a single set. FIRST LEGO League allows the use of almost all LEGO parts (check with your local organizers for any restrictions). This means you can explore attachments built with SPIKE Prime, EV3, NXT, Technic, Robot Inventor — practically any LEGO set. Learn from different designs, get inspired, and share ideas with your team. You can also easily purchase additional parts online.
You can’t truly prepare for competition without mastering the use of sensors. Learn how to follow lines and position your robot on the field using Color/Light sensors, track movement and orientation with the Gyro sensor, and organize your code with State Machines to separate different stages of your program.
What you should focus on is learning how to position your robot reliably and consistently on the field, starting from the base.
LEGO Education SPIKE Prime can be programmed using both Scratch and Python. The Scratch-based version of the SPIKE App can be downloaded to your computer, or you can use the online version available at the SPIKE LEGO Education website.
Scratch is easier to start with and it is not less powerful than Python.
Mindstorms EV3 robots were originally programmed using the LEGO Mindstorms EV3-G software, which is now deprecated. However, you can also program them using Scratch, offering a more modern and accessible approach.
Learn advanced programming techniques like driving straight and using state machines. These skills solve one of the most common competition problems: how to move straight — or at least straighter — for consistent, reliable runs.
See all Testimonials.
