Constructing a robot base

Robot Design Ideas for Chassis with Mindstorms EV3. Base 1

Five different robot chassis. This is the goal of the series. To present ideas for different design of the robots and especially the robot bases. If the base is stable and balanced, then in could easily be extended. Let's start with the most simple of the five. 

Some of the designs would include robots with four motors. All of the designs include sensors and preferably two of them.

Find the full course at:

Robot Design Ideas for Chassis with Mindstorms EV3

LEGO Mindstrorms EV3 Robot Base with 56mmTiresV1

Building instructions for a LEGO Mindstorms EV3 Robot Base with 56mm Tires, Version1. The robot base could be used in robotics competitions as FIRST LEGO League, World Robotics Olympiad and others

First we start with...

First we start with some basic robot constructions that will show you different options for mounting the motors and the sensors. Take a look at the next videos with examples and explanations on five different constructions and the advantages and disadvantages about each of the constructions.

Base 2

The second construction of the series along with a comparison with the first construction. The new robot requires more parts, but has a few more advantages. 

The motors are well attached to the base. The robot also has more wheel at the back to take on more weight. This, in the general case, could make it more stable and precise. The wheels used are from the NXT set, but you could easily change them to wheels available in the EV3 set.

Find the full course at:

Robot Design Ideas for Chassis with Mindstorms EV3

Robot with Front Wheels

A LEGO Mindstorms EV3 Chassis with wheels at the front. Built with the EV3 set you can use this robot chassis as a base for extending with attachments. 

Base 3

The third robot has the brick and motors placed vertically. This is quite unusual and difficult, but the construction is very powerful because it saves space.

The robot is shorter than the previous two, which is a great advantage because it could move through narrow entrances. 

The robot also has a good frame around it. This allows for more attachments to be added to the construction and the robot could become very powerful. 

The wheels on this robot are also attached in a very good way. The axles supporting them is attached to two. 

Be careful also with the center of mass. Check out the video.

Find the full course at:

Robot Design Ideas for Chassis with Mindstorms EV3

Vertical Robot Base Chassis for LEGO Mindstorms EV3

This LEGO Mindstorms EV3 robot chassis has the brick positioned vertically. Interesting idea that could be very useful.

Base 4

Probably the robot I like the most from this series of five robots. See the video to understand why and what is interesting and special about this robot. 

There is almost nothing we should add to or remove from this robot. It is stable, it has the frame and attachments could be easily added.

The motors direction could also easily be changed. 

The whole construction is separated in different modules that allow for fast assembling or disassembling. 

The full course is at:

Robot Design Ideas for Chassis with Mindstorms EV3

Back Wheels Reversible Motor

Building instructions for a LEGO Mindstorms Base Chassis with a reversible motor

Base 5

The last fifth construction is larger compared to the previous constructions. It is wider. It has four sensors and you can take a larger load all by keeping the robot stable. 

We have the motors vertically and the brick horizontally. The two wheels are exactly in the middle in the construction and there is no third wheel. You can decide where to place the third and the fourth wheel. It is entirely up to you and this gives you an opportunity to decide if you would like to make the robot unbalanced.

Find the full course at:

Robot Design Ideas for Chassis with Mindstorms EV3

LEGO Mindstrorms EV3 Robot Base Chassis 5 - The Big One

Building instructions for this LEGO Mindstorms EV3 robot base that could be used in FIRST LEGO League, World Robotics Olympiad and other robotics competitions

Next we move to the...

Next we move to the first Competition construction that you can directly use. If you have an EV3 robot take a look at this constructions the process of building it and the improvements that one of our users made on it

How to build an EV3 LEGO Mindstorms Competition Robot Construction

In this episode we introduce a LEGO Mindstorms EV3 version of competition robot construction. It is a modular construction, with medium motor for aditional attachments and two light or color sensors for orientating on the field.

In the video we take a look at the construction and point out some key characteristics of the construction. Under the materials tab you can find pdf instructions for building the construction from the tutorial. Use the video as a reference to lock the modules together.

If you find the robot too wide, just take out the side frames. If you do not posses two EV3 color sensors, do not worry, just use old NXT light or color sensors.

For any suggestions or questions, just post your comment bellow.

EV3 Competition Robot Full

Building instructions for a Full LEGO Mindstorms EV3 Competition Robot that could be used in LEGO Robotics competitions

EV3 Competition Robot Light

Building instructions for a Light LEGO Mindstorms EV3 Competition Robot that could be used in LEGO Robotics competitions

EV3 Competition Robot Full

Building instructions for a Full LEGO Mindstorms EV3 Competition Robot that could be used in LEGO Robotics competitions

The process

In Episode 58 we introduced you to a LEGO Mindstorms EV3 Modular robot. In this tutorial, we show you how we reached that construction. We start from a construction found on the Internet and take you through the process of examining and improving it, till we reach a more stable and reliable robot.

You could find building instructions for the initial version of the robot under the materials tab and also take a look at Episode 58 for building instructions of the end version of the robot.

In this tutorial we take a look at several problems of the initial constructions found on the Internet:

  • the Back Wheel - it should be firmly attached to the robot. Best case is when the weight is uniformly distributed and falls on as much surface as possible.

  • the Axles of the Front Wheels - usually, when the axle of the front wheel is attached just to the motor it is loose and bend under the weight of the robot. This is why we built an outer frame to hold the axle.

  • the light or color sensors - it is always better if they have covers, which isolates from outer light, and are closely to the ground. For more on this take a look at Episode 3.

  • the whole robot is modular - that is not necessary, but always can be useful later, when you want to modify your construction.

In the next part we will improve the robot even further. Meanwhile we will be glad to hear from you, so do not forget to comment bellow.

Arrow designed by Juan Pablo Bravo from the Noun Project.

Instructions for building the final robot:

EV3 Competition Robot Light

Building instructions for a Light LEGO Mindstorms EV3 Competition Robot that could be used in LEGO Robotics competitions

Improvements by Mic Lowne

In Episode 58 we introduced you to an LEGO Mindstorms EV3 Modular robot. Mic Lowne wrote to us and had that robot remade, because it used too many blue lego pins and could not be build using one EV3 kit.

Your turn

Did you like the remade robot? I would love to hear your suggestions for improving the copetition robot even more!

Let us know in the comments below!

EV3 Competition Robot by Mic Lowne

The instructions for building the improved EV3 Competition Robot by Mic Lowne

If you happen to ha...

If you happen to have an NXT robot we have made a constructions of LEGO Mindstorms NXT robots and we have provided to teams for the 2011, 2012, 2013 competitions. 

NXTs are currently already obsolete and not supported, but are very good robot still in used today.

NXT Competition Robot Construction

In this lesson I would like to show you how to build a LEGO Mindstorms competition robot and tell you how we have designed the construction used in the videos so far. Surely it isn’t perfect, but it is a good start.

Winning the competition depends on a solid, robust and extendable base LEGO Mindstorms construction for the robot. Attachments are most of the time dependent on the specific mission, but a good base could save you many days of hard work when preparing for the competition.

There are three main topics when it comes to base constructions:

  • What is the perfect size for out robot, while we keep the constuction balanced? 

  • What tires to use for the robot?

  • Where and how shall we put the sensors and attachments?

and we mention all of them in this lesson.

Feel free to use this base, explore and extend it. Get in touch with us if you do so. It would be very helpful for us :)


NXT Competition Robot - LEGO Digital Designer instructions

Third motor and light sensors

Motor one

Motor two


NXT Competition Robot - Instructions

The Brick

Parts for the brick

Now it's the ti...

Now it's the time for you to construct a robot that could be used for programming in the next module of the course. Choose one of the previously shown robots, like the two version of the EV3 competition robots or NXT competition robot

Task normal icon Construct the EV3/NXT competition robot

It should be possible to construct it from one EV3 basic+resource set

Task advanced icon Are any modifications needed to the robot construction?

It might be tempting at this stage to make a few modifications of the robot. You have watche the videos for a few different constructions so it is a good chance to select a construction based on them. 

If you really need to share them with us using the comments section so that we could return some feedback to you.

Finally in this mod...

Finally in this module we add a video on Caster Wheels (one of our very first videos). Especially with the EV3 robots and the steel ball included with them the caster wheels are not that popular any more, but understanding how they work could make a lot of the difference in the gathered points. Especially if you need to use them.

LEGO Mindstorms Caster wheels

In this video tutorial we will show you three ways for making your robot stable on the field. We will present each one of them with their advantages and disadvantages - it's up to you to choose which one is the best for your case.

As you have the rob...

As you have the robot constructed now do some tests with it. This means moving it forward and turning with it so that you can see how stable and precise the robot is - spoiler alert - no robot is could stable and precise enough to go at a competition without the use of sensors.

Task easy icon How precise is your robot? - move forward

Test the robot on moving forward. Just start the motors and let it move forward for 2-3 meters. Mark the end location of the robot. Do this again and mark again the end location. Do it a couple of time and you will see that each time the robot arrives at a different place.

Task normal icon What about turning?

Do the same experiment with turning - move forward, turn left, move forward, turn right. You will see the the robot will arrive at a different position each time. 

Task advanced icon Derive a conclusion

The consclusion should be simple, but only the winning teams can make it. And it is -> always use sensors to position the robot on the robot field. Always.