Lego Submarine Gets Balloon Ballast System

Lego is a fun building block which vast numbers of the world’s children play with every day. However, the mechanical Technic line of Lego building blocks has long offered greater options to the budding engineer. [Brick Experiment Channel] is one such soul, working hard on their latest Lego submarine.

The sub is built inside of a glass food container, chosen for its removable plastic lid with a watertight seal. This keeps all the mechanics dry, as well as the custom electronics built to allow a 27MHz RC controller to send signals to the Lego electronics. This is key as higher frequency radios such as Bluetooth or WiFi can’t penetrate water nearly as well.

A magnetic coupling fitted to a Lego motor is used to drive the propeller in the water without the leaks common when trying to seal a rotating shaft. A second coupling on a Lego servo along with a creative steering arrangement allows the propeller to be turned to steer the craft.

The ballast system is simple. A balloon is filled by a Lego motor running an air pump, capable of 3.0 mL a second and capable of creating a maximum pressure of 2.0 bar. When the balloon is inflated, the buoyancy goes up and the sub rises. Run the motor the other way and the balloon is emptied by a clever clutch and valve arrangement, reducing buoyancy and causing the sub to sink.

The sub isn’t perfect. Maintaining a set depth underwater can be difficult with the rudimentary ballast system, perhaps as the balloon changes shape with varying water pressure. Sometimes, Lego axles slip out of their gears, too, and the radio only works for a few meters under water.

However, simply building a Lego sub of any sort is a remarkable feat. It’s interesting to see the variances in the design compared to earlier projects from [Brick Experiment Channel], too, as we’ve featured their earlier subs before. Video after the break.

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DIY LEGO Record Cleaner Is Revolutionary

There are many schools of thought when it comes to keeping vinyl records clean. It’s a ritual that’s nearly as important as the one that comes after it — queuing up the record and lowering the needle. We’ve seen people use everything from Windex and microfiber towels to ultrasonic cleaning machines that cost hundreds or even thousands. In the midst of building a beefier ultrasonic record cleaner and waiting for parts, [Baserolokus] looked around at all the LEGO around the house and decided to build a plastic prototype in the interim.

The idea behind ultrasonic cleaning is simple — high-frequency sound waves pumped through distilled water produce tons of tiny bubbles. These bubbles gently knock all the dirt and grime out of the grooves without using any brushes, rags, or harsh cleaners. [Baserolokus] built two pieces that hang on the edge of a washtub. On one side, a Technic motor spins the record at just under one RPM, it spins against a 3D printer wheel embedded in the other side. Check it out in action after the break.

Cleaning your vinyl is a great first step, but you might be ruining your records with a sub-par turntable. Take a deep dive with [Jenny List]’s thorough primer on the subject.

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Lego Tank Fires Soccer Ball Cannon

Back in the 20th century, Lego Technic was a popular toy designed to teach kids about mechanical technology, and be a lot of fun to boot. Motors and pneumatics were available, but by and large you had to move your creations and make the noises yourself. That’s not the case these days, as the [Brick Experiment Channel] demonstrates with this impressive Lego tank.

The drivetrain is straightforward, using standard Lego tank treads with each side given its own motor for easy skid steering. However, the real party piece is the slingshot cannon, which launches Lego soccer balls at 60 km/h. Utilizing several motors, it’s complete with elevation adjustment for accurate ranging, and a 6 round magazine so you can (slowly) prosecute your targets with rounds downrange.

What really makes this build great is the control system, with the tank being controlled by a PS4 controller via Sbrick, a device that lets Lego motors be controlled via Bluetooth. We’d love to build a couple of Lego vehicles and have them blast away at each other. We’ve seen the technology used before for a secret heist robot. Video after the break.

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A Whimsical Touch-Free Gumball Machine For These Trying Times

It sucks that certain stuff in public is off-limits right now, like drinking fountains and coin-operated candy and gum machines — especially the fun kind where you get to watch your gumball take a twisting trip down the tower and into the collection bin. Hopefully there will be commercial contact-free machines one of these days that take NFC payments. Until then, we’ll have to make them ourselves out of cardboard and whimsy and Micro:bits.

[Brown Dog Gadgets] also used one of their Crazy Circuits Bit Boards, which is a Micro:bit-to-LEGO interface module for building circuits with conductive tape. There’s a distance sensor in the rocket’s base, and a servo to dispense the gumballs. This entire build is fantastic, but we particularly like the clever use of a LEGO Technic beam to both catch the gumball and prevent the next one from going anywhere. You can see it in action after the break.

Wave hand, receive gumball is about as simple as it gets for the end user. The three robots approach takes much more work.

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Lego Ziplining Robot Climbs For Claps

The internet has given us plenty of cool robotics projects, but we don’t think we’ve seen one zipline before. At least not until now.

This cool little ziplining robot is courtesy of the folks over at [Tart Robotics]. As they described it, the robot moves using a 4-bar linkage mechanism with the motor’s torque “transferred to the arm mechanisms through a pair of bevel gears and a worm drive.” Even cooler, the robot is activated by clapping. The faster you clap, the faster the robot moves. That’s sure to wow your friends at your next virtual hacker meetup.

They had to do a bit of custom 3D printing work to get a few of the Lego components to connect with their non-Lego off-the-shelf bits, so that took a bit of time. Specifically, they had some cheap, non-branded DC motors that they used that did not naturally mate with the Lego Technic components used to create the rest of the robot’s body. Nothing a few custom 3D printing jobs couldn’t solve.

It always amazes us what cool contraptions you can put together with a few Lego blocks. What’s your favorite Lego project?

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Wandel Weaponizes Waste With Lego And A Raspberry Pi

Before 3D printers, there was LEGO. And the little bricks are still useful for putting something together on the quick. Proof is YouTuber [Matthias Wandel]’s awesome bottle cap shooter build that uses rudimentary DIY computer vision to track you and then launch a barrage of plastic pieces at you.

This is an amazing project that has a bit of something for everyone. Lets start with the LEGO. [Matthias Wandel] starts with making a crossbow designed launcher and does an awesome job with showing us how it works in a video. The mechanism is an auto reloading and firing system that can be connected to a stepper motor. Next comes the pan and tilt mechanism which allows the turret to take better aim at moving targets: more LEGO and stepper motors.

The target tracker uses color matching in a program that curiously uses no OpenCV. It compares consecutive frame and then filters out red objects – the largest red dot is it. Since using a fisheye lens on the Raspbery Pi camera adds distortion, [Matthias Wandel] uses a jig made with more Legos to calibrate the image.

The final testing involved having his own child walk around the room being hunted but the autonomous machine. Kids do love toys even if they are trying to shoot bottle caps at them.

Want more Lego inspiration? Check out the Lego Quadcopter Mod and the Lego Tank with the ESP8266.

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Mini LEGO Technic Tank Patrols Your Desk Under ESP32 Control

We probably don’t have to tell the readers of Hackaday that LEGO isn’t just for kids; we’ve seen plenty of projects that live in an enclosure made of the multi-color bricks, and let’s not even get started on the Mindstorms builds we’ve seen over the years. But while LEGO (and especially the Technic product line) is fine for prototyping and putting together quick projects, the stock electronic components aren’t exactly top of the line. Which is why [Jason Kirsons] has been working on bridging the gap between LEGO and “real” parts.

His LEGO Technic tank is a perfect example of this principle. While the tank design itself is standard LEGO fare, he’s gone all in on the electronics. With an Adafruit Feather ESP32, custom motor controller board, and NEMA 8 steppers with 3D printed Technic adapters, this little tank has a lot more going on under the hood than you might expect. While this project is more a proof of concept than anything, the methods [Jason] demonstrates might be something to consider the next time you’re building with Billund’s best.

[Jason] chose the Feather ESP32 because of its small size, but you could get away with a generic board if you’re not trying to compress everything down into such a small footprint. Of course, if you go with another board you won’t be able to use the PCB he’s designed which attaches to the Feather and holds four Pololu DRV8835 motor drivers.

Easily the most broadly applicable element of this project is the work [Jason] has done designing adapter plates that let you use NEMA 8 motors with LEGO Technic parts. He’s put the adapters up on Thingiverse, for anyone looking for a drop-in solution to give their Technic creations a bit more oomph (technical term).

LEGO has a long history with hackers and makers. We’ve covered some absolutely incredible projects built with the famous construction set, and we don’t see any sign of it slowing down in the future.

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