LEGO Mindstorms Robo Dog: Ressi 37

The Ressi 37 is a very cute robot dog built using just a single LEGO MINDSTORMS Robot Inventor 51515 kit, so as long as you have the kit, you don’t need anything else to create this robot.

Ressi 37 actually has a wagging tail powered by the front right leg motor. It uses quite a clever mechanism to achieve this. If you’re interested in learning about this mechanism, then please click on the following video.

So how do you control Ressi 37? He has four modes. You can cycle through them by pressing the right arrow button on the hub. Pressing the left arrow button will activate the selected mode. To escape the mode, simply press the left arrow button again.

In mode 1, Ressi 37 enters autonomous mode. He will walk forward until he sees an obstacle within 37 centimeters ahead of him. Then, Ressi 37 will turn randomly either left or right, and continue walking forward. A real-ly interesting part of autonomous mode is that the robo dog constantly checks the relative angular position of the legs. Meaning, as soon as one of them gets out of sync, the robo dog stops, resynchronizes, and then continues walking forward.

In mode 2, Ressi 37 will start dancing. The music is a portion of the same music used in the NXT 2.0 MORPH robot by Kirk Backstrom. Full credit to him for the choice of music.

In mode 3 and 4, Ressi 37 will turn around about 180 degrees in the re-spective direction.

To build this robo dog, all you need is just 1 LEGO Mindstorms 51515 kit. Prior to installing this program, make sure to delete every program from the hub, then restart the hub, and then install this program. This is very important since this program takes up most of the hub’s storage.

Please email any feedback you have about this robot to: contact@unbrickme.com

Please post pictures of your robot to instagram with #unbrickme so that I will be able to view your post and I will like your post. If you let me know that you posted a picture of my robot dog to instagram, I will share your post on the community tab of my YouTube channel. If you wish to post a video about my robot to YouTube, please, feel free to do so! Once you have posted a video, please let me know via email and I will feature your video on the community tab of my YouTube channel.

LEGO Mindstorms Beta Rex

The Beta Rex robot is built using only the pieces found in the LEGO MINDSTORMS Robot Inventor 51515 kit. As long as you have this kit, you will be able to build this robot!

My goal when designing the Beta Rex was to create a successor to the LEGO MINDSTORMS NXT 1.0 and 2.0 Alpha Rex robots. These robots were awesome walking humanoid robots that showed what’s actually possible with MINDSTORMS. Sadly, since the release of the EV3 system, the walking humanoid robots got replaced with those that used tracks or wheels as their feet, completely eliminating the walking motion.

Fortunately, I have created free building instructions and programs so that you can build this robot yourself! If you remember the old Alpha Rex robots, then you will love Beta Rex! But first let’s go over how to control the LEGO Mindstorms 51515 Beta Rex!

The main program, both the python and scratch 3.0 version, use the hub’s buttons and the color sensor as an input that tell Beta Rex what to do!

If the color sensor detects green, then Beta Rex will enter autonomous obstacle avoidance mode. He will walk forward until he sees an object, then he will randomly turn either left or right, and then he repeat this cycle until the color sensor detects red, which is the color used to stop the robot.

If the robot detects blue, he will dance once, and then wait for your next command!

If the robot detects yellow, he will grab or release with his right hand! Best of all, you can have the robot enter autonomous obstacle avoidance mode while he is holding an object!

There’s also a full RC version of the program for Beta Rex, so if you want to manually control your robot from your computer, phone or tablet, then simply use the RC code.

Below are three versions of the code, the main scratch 3.0 version, the python version, and the full RC version! Click the button “Download” to get free building instructions and programs!

LEGO Mindstorms Robot Inventor VS EV3: Which one should you buy?

Christmas season is nearing! There’s no better way to celebrate Christmas than with LEGO Mindstorms, which is an excellent LEGO robotics platform, which allows you to create robots from your LEGO bricks. LEGO Mindstorms is meant to be primarily used with Technic elements, which are specialized LEGO parts that use axles, pins, holes, gears, and other more mechanical methods of connecting bricks together! LEGO Mindstorms allows you to create some insane robots, which incorporate speed transmission gearboxes and other mechanical features. The only problem is, LEGO sells two Mindstorms sets, the EV3 and the Robot Inventor kit. So, the question is, which one should you buy?

Taking a look at five advantages of each robotics system is crucial to understand which one is better for you. If you would like to get a more in depth analysis of the new robotics system, check out the full review video on the Unbrickme YouTube channel! First, let’s discuss the EV3 system!

1. EV3 Daisy Chaining

The daisy chaining functionality of the EV3 allowed you to connect up to four EV3 intelligent bricks (computers of the robots) together! Each EV3 Brick could have four motors and four sensors connected, and with daisy chaining, robots could have up to sixteen motors and sixteen sensors all contributing to one robot! The daisy chaining functionality greatly expanded the LEGO robotics potential, and it is one of the reasons why the EV3 system is still beloved by the overall community.

2. Greater Community Contributions

The LEGO Mindstorms EV3 System was originally released in 2013. This allowed seven years for the community to make contributions, such as designing their own robots with public instructions, making tutorials, publishing books, and much more! By purchasing the EV3 system, you get access to all the community benefits! Want some EV3 books? No problem! There’s a huge collection available on Amazon! Want some EV3 tutorials? No problem! There’s an abundance of tutorials on YouTube! However, because the system is seven years old, it also means that as computers get upgraded, it is likely that support for the EV3 programming software will end soon.

3. More Third Party Options

The new LEGO Mindstorms Robot Inventor System was released just recently, which means that third party sensors are still too early in development. However, because the EV3 System used the old Mindstorms cables, it meant that every third party sensor that has been in development since 2006, was completely compatible with the EV3 system! Every single hitechnic sensor that was designed for the NXT (predecessor to the EV3), was completely compatible with the EV3, since it used the old cables. The new system switched to the new Powered Up cables, which rendered all the old sensors obsolete. You could also connect a third party camera sensor to your EV3! This allowed for some incredible robots!

4. SD Card Expansion

The EV3 Brick has 16mb of internal storage for all your programs. However, with the micro SD card expansion, you could increase this internal memory to 32 gigabytes! This allowed your imagination to be limitless! It also allowed users to create incredibly advanced and complex programs! Even though the LEGO company’s official recommended age for mindstorms is 10+, the mindstorms community is actually primarily run by adults. For example, all of the the mindstorms book are published by adults. Because of this community interest, it means that the robotics system of LEGO mindstorms has received some incredible treatment by the community! People have created advanced machine learning algorithms with the EV3 system!

5. Cables

Unlike with the new system, the cables in the EV3 system are interchangeable! You could pick the ideal cable length for each sensor and motor based on how your robot was designed. Unfortunately, the new system does not get this treatment, and you are limited to the cable length you get. Yes, there are some third party options for cable extension, but it still means that if the provided cable length is too long, it will be problematic for your robot.

Now let’s discuss the advantages of the new LEGO Mindstorms Robot Inventor system!

1. Absolute Positioning Motors

Previously, with the EV3 system, you had to use touch sensors in order to synchronize the position of your motor. Synchronizing positions for motors is crucial with walking robots. If the legs aren’t properly synchronized, the robot will not properly walk. While you did have relative positioning with the EV3 system, it was only good if there was some sort of physical limiter for the motor, which is not how walking robots work. Walkers must have their motors spin theoretically infinitely. For example, you could use relative positioning for synchronizing steering with the EV3 system. You could simply move the steering motor with unregulated power all the way to the right. Then use unregulated power again to move the steering motor to the left while also counting the number of degrees it takes for the motor to turn, divide that by two, turn the motor right by that number of degrees, and set the relative position to zero (since this position is the center of the steering). So, absolute positioning was perfect for autonomously synchronizing walking robots, without the need for touch sensors!

2. Internal 3-axis Gyro Sensor

Previously, with the ev3 system, you had to use an external gyro sensor. These gyros were also only based on one axis. Essentially, with the new system, it’s like you’re getting three gyro sensors, but all internally! This is incredibly useful for making sure that your robot rotates only a certain amount of degrees! It is also incredibly useful for creating some insane robots, like self balancing Segway robots!

3. Force Sensor

Previously, with the EV3 system, you had to use basic touch sensors. These were essentially just buttons, and nothing more. However, the new system actually allows you to use the force sensor! The force sensor actually measures the amount of force that you’re pushing the button with! This is pretty useful for knowing just how much your robot bumped into something, or to have different functions activate based on the amount of force that you’re pressing the force sensor with!

4. Powered Up Compatibility

Because the new system uses the Powered Up cables, it means that the new system is actually fully compatible with every single powered up motor! Powered Up motors share approximately the same form factor as the Power Functions motors, meaning that you can finally create incredibly compact robots! While you could theoretically connect the EV3 to Power Functions motors, it didn’t serve much purpose since those motors didn’t have internal rotation sensors. Because the new powered up motors actually have built in rotation sensors, you can use the powered up motors in robotic applications! Instead of having to use the standard Technic Hub with your powered up creations, which has no navigation, no internal memory, no computer, and only four ports, you can finally use the much more advanced mindstorms hub with the powered up system!

5. Better Kit

The new LEGO Mindstorms 51515 kit is simply better than the LEGO Mindstorms 31313 kit! The new kit contains 949 pieces, but the old kit only contains 606 pieces! The pieces in the new kit are also updated, meaning that you can create robots more efficiently! The old kit contains two large motors and one medium motor, but the new kit contains four medium angular motors, with absolute positioning! The older EV3 kit contains one touch sensor, one color sensor, one infrared sensor, and one IR remote control, but the new kit contains only a color sensor and one ultrasonic sensor. However, you can still get those same remote control possibilities, since you can use your mobile device and control your robot via bluetooth. Because you’re not limited to just the physical controller, you can actually customize your bluetooth controller, which is a huge advancement! You’d need to purchase the force sensor separately with the new kit.

Conclusion: If you want better long term support and powered up compatibility, then get the new Robot inventor system. If you want to get the benefits of daisy chaining and community contributions, get the EV3 system.

Did you know, the programming possibilities of the Spike Prime and Robot Inventor app are different? That’s right, as of right now, you actually get more functionality in the Spike Prime app. For instance, in the Robot Inventor app, the only gyroscope reading you’re able to get is the angle, and you don’t have a block for the angular velocity. The angle is calculated by integrating the angular velocity, so the robot is using a hidden angular velocity value that you’re unable to access in the robot inventor app.

This is where the Spike Prime app is a saving grace! The app has a block for the angular velocity in degrees per second! This is extremely useful for things like self balancing Segway robots, since you need to combine both the angular velocity and the angle into the PID controller. The hub’s angles are factory calibrated, and cannot be user reset. The hub has a problem in which degree count won’t go beyond 180 degrees, and will instead start counting from -180 degrees. When your hub is positioned between angle 180 and -180, it can be very frustrating, since negative numbers flip your code completely upside down. There’s a very easy solution to this, just get the angle from the angular velocity with the following code:

The Spike Prime app also has a very useful Raw Color block, which essentially gives you an accurate value of 0 – 255 for either red, green, or blue. This opens up a plethora of possibilities, since now the color sensor is able to detect much more colors than just eight.

You also get the acceleration block, gesture block, orientation block, and the set orientation block, which have a bunch of fun applications! Since the Spike Prime and the Robot inventor 51515 hubs are completely identical to each other with the exception of the color, both can be used with either programming app.

However, you need to update your hub’s firmware for the respective app, which is very easy. After plugging in the hub to your computer, both apps will give a firmware update window, and all you need to do is start the update. You need to activate “more sensors” in the spike prime app in order to gain access to these blocks.

LEGO Mindstorms Babka

Babka is one of my favorite LEGO Mindstorms Robot Inventor projects I have created. This amazing robot was heavily inspired by Laurens Valk’s NXT Hopper robot, as it walks using the same exact concept. Babka moves with the help of the walking frame and the middle 5th leg. When the walking frame is up, the 5th leg is on the ground. The 5th leg is also connected to a turntable, so whenever the legs are up, the 5th leg simply turns, and that’s how the robot turns. Please watch the following video to see how the robot moves.

The code very simple, as it’s just an obstacle avoidance program. Whenever Babka sees an obstacle closer than 53 centimeters, it will randomly turn either left or right, and then continue walking.

Best of all, you only need a single LEGO Mindstorms Robot Inventor 51515 kit, since it contains all the required parts!

Please download the building instructions and program below.

LEGO Mindstorms Robot Inventor VS EV3: Which one should you buy?

I’ve always felt like the gearbox in the LEGO Technic Heavy Duty Exacator was a missed opportunity! No problem! I modified mine to include a distribution! Now, one knob will control both the linear actuators independtly.

Download the complete instructions for the modification:

The LEGO Technic BMW M1000 RR 42130 Motorcycle has been officially revealed! This is exactly the type of winter set I’ve been dreaming of! It is packed with many functions!

First, it features a highly advanced 3 speed transmission powering the 4 cylinder inline engine. The real motorcycle has 6 speeds, but the size probably didn’t allow for a larger gearbox.

The motorcycle is detailed to the maximum! It has the perfect combination of both aesthetics and advanced technic functionality.

The set contains 1920 pieces and will retail for $229.99 which could be considered overpriced, but the motorcycle includes a lot of specialized pieces, such as the incredible shock absorbers!

Still, the LEGO Technic 6×6 Volvo Articulated Hauler retailed for only $20 more and it contained 273 more pieces along with the Control+ hub and 3 motors, along with a 3 speed transmission. This makes the articulated hauler a far better deal.

I really hope that we get more motorcycles like the 42130, since this is definitely the right direction for LEGO Technic.

Getting Started with LEGO Technic

With the new LEGO Technic Winter 2022 release, there have been several welcome additions to the technic line. If you are just looking to start out, which one should you buy?

First, let’s examine the LEGO Technic Motorcycle 42132 which is a very easy purchase, coming in at only $12.99.

Despite the low price, this set offers a surprisingly good amount of functionality! We even get an actual working 3 cylinder inline engine.The way the cengine is done at some a small scale is actually pretty genius! The tiny studded pins are used as cylinders!

Honestly, you really can’t go wrong with this tiny motorcycle! it’s cheap, functional, and really a great representation of the technic experience at such a low price point! I definitely strongly reccomend this set!

Next up is the Monster Jam El Toro Loco 42135 which retails for $19.99

This set contains 247 pieces and it comes with a pullback motor. It is pretty good for playability, and you can buy multiple of these and have them race eachother!

I don’t like a few things with this car though. First, the massive bumper on the front. I understand that this is done because the car will bump into walls, but the more expensive $50 pullback cars, which are covered in more detail in this article, completely lack that front bumper. It doesn’t actually serve much purpose, and it just looks out of place. Also, the tires here should’ve been the same ones as were used in the LEGO Technic Jeep Wrangler, since that would’ve been way more accurate to the real car.

Still the car looks decent and I like it more than either of the pullbacks of the 2021 winter wave. I appreciate the orange panels, and fun fact, the orange is my favorite fruit, and my favorite drink is orange juice.

Let’s look at the companion car, the Monster Jam Megalodon 42134 which also retails for $19.99.

I mean wow! This looks incredible! Sharks are some of my favorite animals in real life, so I greatly appreciate this car! It just looks phenomenal! Of course, I still have my same criticisms with the front bumper as well as the tires. But the light blue paneling, teeth, and the amazing aethetics really make up for that. If you are looking to just get one small pullback set, then this is the choice for you. Still, I think that the smaller $13 motorcycle is a much better representation of what LEGO Technic is actually about, mechanisms!

Next up is the LEGO Technic Formula E Porsche 99X Electric set number 42137, which retails for $49.99.

At first glance, this car seems like a great presentation piece, and it even features two pullback motors with a release mechanism. Furthermore, since the real version of this car is electric, there couldn’t have been an engine or much functionality in this car to begin with. So conceptually, this seems great!

However, this car is fundamentally flawed. The front looks extremely unfinished and the chassis is just out in the open. Most technic cars at this scale have far better detailing.

Don’t get me wrong, the pullback feature is incredibly fun, and I love racing the the Ford Mustang. But the front is just strange. When I first built this car, I actually went back in the instructions to check if I did something wrong, because I didn’t feel like the model was complete.

Usually, I don’t cirtisice the aesthetics much, mainly because the sets have other factors to make up for it, such as a gearbox, pneumatics, or other interesting functionality. The only function this model has is pullback.

Next up is the LEGO Technic Ford Mustang Shelby GT 500 set number 42138 which retails for $49.99

Like the Porsche, this car also has the pullback functionality with a release mechanism. Though unlike the porsche, this car looks very well detailed and does not have any unfinished areas.

Since the real version of this car is not electric and has an engine, I think this car should’ve had a working engine in addition to the pullback feature. Furthermore, why not add hand of god steering? With pullback, the car should always go forward in a straight line, so the steering should use a simple return to center mechanism with rubber bands.

Specifically, the engine may add some unwanted friction, which would always put it at a disadvantage when racing against the Porsche, but I think that some cool mechanisms in a medium sized set under $100 would’ve been welcome. I mean, even opening doors are sacrificed in favor of pullback, which is just strange considering it has zero effect on the speed or acceleration.

I don’t think this set is overpriced, and I do still consider it to be much better than the Porsche.

Finally, we have the beloved LEGO Technic BMW M100 RR Motorcycle set number 42130 which retails for a whopping $230

This motorcycle is absolutely phenomenal! Seriously!!! It is nearly flawless except for the price tag. We get plenty of new pieces and functionality! This is also the largest LEGO Technic motorcycle ever! We definitely need more sets like this in the near future!

It has a 3 speed transmission with a neutral, with an awesome shifting mechanism. The suspension is phenomenal too!

Conclusion: The best, and easiest set to get started with, that also provides a good impression of that LEGO Technic is all about, is the 42132 Motorcycle. It is one of the most functional tiny technic sets ever! Furthermore, it is a ton of fun to play with!

The complete parts list for the LEGO Technic All Terrain Vehicle 42139. Simply click on the download button.