Robots Hacks

2347 Articles

“The Cow Jumped Over The Moon”

October 6, 2017 by 12 Comments

[Ash] built Moo-Bot, a robot cow scarecrow to enter the competition at a local scarecrow festival. We’re not sure if Moo-bot will win the competition, but it sure is a winning hack for us. [Ash]’s blog is peppered with delightful prose and tons of pictures, making this an easy to build project for anyone with access to basic carpentry and electronics tools. One of the festival’s theme was “Out of this World” for space and sci-fi scarecrows. When [Ash] heard his 3-year old son sing “hey diddle diddle, the cat and the fiddle…”, he immediately thought of building a cow jumping over the moon scarecrow. And since he had not seen any interactive scarecrows at earlier festivals, he decided to give his jumping cow a lively character.

Construction of the Moo-Bot is broken up in to three parts. The skeleton is built from lumber slabs and planks. The insides are then gutted with all of the electronics. Finally, the whole cow is skinned using sheet metal and finished off with greebles to add detailing such as ears, legs, spots and nostrils. And since it is installed in the open, its skin also doubles up to help Moo-bot stay dry on the insides when it rains. To make Moo-Bot easy to transport from barn to launchpad, it’s broken up in to three modules — the body, the head and the mounting post with the moon.

Moo-Bot has an Arduino brain which wakes up when the push button on its mouth is pressed. Its two OLED screen eyes open up, and the MP3 player sends bovine sounding audio clips to a large sound box. The Arduino also triggers some lights around the Moon. Juice for running the whole show comes from a bank of eight, large type “D” cells wired to provide 6 V — enough to keep Moo-Bot fed for at least a couple of months.

Check out the video after the break to hear Moo-bot tell some cow jokes – it’s pretty funny. We’re rooting for it to win the competition — Go Moo-bot.

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Friction Differential Drive Is A Laser-Cut Triumph

October 2, 2017 by 6 Comments

Here on Hackaday, too often do we turn our heads and gaze at the novelty of 3D printing functional devices. It’s easy to forget that other techniques for assembling functional prototypes exist. Here, [Reuben] nails the aspect of functional prototyping with the laser cutter with a real-world application: a roll-pitch friction differential drive built from just off-the shelf and laser-cut parts!

The centerpiece is held together with friction, where both the order of assembly and the slight wedged edge made from the laser cutter kerf keeps the components from falling apart. Pulleys transfer motion from the would-be motor mounts, where the belts are actually tensioned with a roller bearing mechanism that’s pushed into position. Finally, the friction drive itself is made from roller-blade wheels, where the torque transferred to the plate is driven by just how tightly the top screw is tightened onto the wheels. We’d say that [Reuben] is pushing boundaries with this build–but that’s not true. Rather, he’s using a series of repeatable motifs together to assemble a both beautiful and complex working mechanism.

This design is an old-school wonder from 2012 uncovered from a former Stanford course. The legendary CS235 aimed to teach “unmechanically-minded” roboticists how to build a host of mechanisms in the same spirit as MIT’s How-to-make-almost-Anything class. While CS235 doesn’t exist anymore, don’t fret. [Reuben] kindly posted his best lectures online for the world to enjoy.

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Researchers Squeeze Out A New Breed Of Robot Locomotion

September 30, 2017 by 24 Comments

Researchers have been playing around with various oddball forms of robot locomotion; surely, we’ve seen it all, haven’t we? Not so! Lucky for us, [researchers at Stanford] are now showing us a new way for robots to literally extrude themselves from point A to point B.

This robot’s particular motion for mechanism involves unwinding itself inside out. From a stationary base, a reel caches meters of the robot’s uninflated polyethylene body, which it deploys by pressurizing. Researchers can make full 3D turns by varying the amount of inflated air in outer control chambers. What’s more, they can place end effectors or even payloads at the tip of the growing end with their position held in place by a cable.

As we can imagine, any robot that can squeeze its way up to 72 meters long can have dozens of applications, and the folks at Stanford have explored a host of nooks and crannies of this space. Along the way, they deploy complex antenna shapes into the air, deliver small payloads, extinguish fires, and squeeze through all sorts of uninviting places such as flytraps and even a bed of nails. We’ve placed a video below the break, but have a look at Ars Technica’s full video suite to get a sense of the sheer variety of applications that they imparted upon their new creation.

Biomimetics tends to get us to cry “gecko feet” or “snake robots” without thinking too hard. But these forms of locomotion that come to mind all seem to derive from the animal kingdom. One key element of this soft robot is that its stationary base and vine-like locomotion both have its roots in the plant kingdom. It’s a testament to just how unexplored this realm may be, and that researchers and robots will continue to develop new ways of artificially “getting around” for years to come.

Thanks for the tip, [Jacob!]

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Earth Rovers Explore Our Own Planet

September 29, 2017 by 17 Comments

While Mars is currently under close scrutiny by NASA and other space agencies, there is still a lot of exploring to do here on Earth. But if you would like to explore a corner of our own planet in the same way NASA that explores Mars, it’s possible to send your own rover to a place and have it send back pictures and data for you, rather than go there yourself. This is what [Norbert Heinz]’s Earth Explorer robots do, and anyone can drive any of the robots to explore whatever locations they happen to be in.

A major goal of the Earth Explorer robot is to be easy to ship. This is a smaller version of the same problem the Mars rovers have: how to get the most into a robot while having as little mass as possible. The weight is kept to under 500g, and the length, width, and height to no more than 90cm combined. This is easy to do with some toy cars modified to carry a Raspberry Pi, a camera, and some radios and sensors. After that, the robots only need an interesting place to go and an Internet connection to communicate with Mission Control.

[Norbert] is currently looking for volunteers to host some of these robots, so if you’re interested head on over to the project page and get started. If you’d just like to drive the robots, though, you can also get your rover fix there as well. It’s an interesting project that will both get people interested in exploring Earth and in robotics all at the same time. And, if you’d like to take the rover concept beyond simple exploration, there are other machines that can take care of the same planet they explore.

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A Robot That Can Still Keep Its Balance After A Night In The Pub

September 27, 2017 by 6 Comments

One of the star attractions at the recent bring-a-hack prior to our London unconference was [Dan]’s two-wheeled self-balancing robot. As the assorted masses of the Hackaday readership consumed much fine ale and oohed and ahhed over each others work, there it stood on a pub table, defying all attempts to topple it.

In a way a successful self-balancer can look surprisingly unexciting because it achieves the seemingly unimpressive task of just standing there and not doing much except trundling about, but to take such a superficial view belies the significant feat of engineering that gives the self-balancer its party trick. And it’s no mean achievement to create one from fairly basic hardware, so how has he done it?

The 3D-printed frame holds a pair of stepper motors to do the hard work, while a piece of stripboard acts as carrier for boards containing the MPU6050 accelerometer and DRV8825 stepper motor drivers. Meanwhile the brains of the whole show started as an Espruino Pico but has since been moved to an ESP32.

There is a linked GitHub repository with all the code, and if our description of seeing it in a London pub isn’t good enough for you then you can see it in action in the video below.

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Pulleys Within Pulleys Form A Unique Transmission For Robots

September 25, 2017 by 36 Comments

After a couple of millennia of fiddling with gears, you’d think there wouldn’t be much new ground to explore in the field of power transmission. And then you see something like an infinitely variable transmission built from nested pulleys, and you realize there’s always room for improvement.

The electric motors generally used in robotics can be extremely efficient, often topping 90% efficiency at high speed and low torque. Slap on a traditional fixed-ratio gearbox, or change the input speed, and efficiency is lost. An infinitely variable transmission, like [Alexander Kernbaum]’s cleverly named Inception Drive, allows the motor to stay at peak efficiency while smoothly changing the gear ratio through a wide range.

The mechanism takes a bit of thought to fully grok, but it basically uses a pair of split pulleys with variable spacing. The input shaft rotates the inner pulley eccentrically, which effectively “walks” a wide V-belt around a fixed outer pulley. This drives the inner pulley at a ratio depending on the spacing of the pulley halves; the transmission can shift smoothly from forward to reverse and even keep itself in neutral. The video below will help you get your head around it.

We’ve seen a couple of innovative transmissions around here lately; some, like this strain-wave gear and this planetary gearbox, are amenable to 3D printing. Looks like the Inception Drive could be printed too. Hackers, start your printers and see what this drive can do.

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Cronk The Gonk Droid

September 20, 2017 by 7 Comments

The ‘Gonk’ droids from the Star Wars universe are easy to overlook, but serve the important function of mobile power generators. Here on Earth, [bithead942]’s life-size replica droid fulfills much the same purpose.

Cronk — functionally an oversized USB charging hub with a lot of bells and whistles — is remotely controlled by a modified Wii Nunchuck very controller similar to the one [bithead942] used to control his R2-D2. With the help of an Adafruit Audio FX Mini, an Adafruit Class D 20W amp, and two four-inch speakers, the droid can rattle off some sound effects as it blows off some steam(really, an inverted CO2 duster). An Arduino Mega acts as Cronk’s brain while its body is sculpted from cast-able urethane foam for its light weight and rigidity. It also houses a FPV camera, mic, and DVR so it can be operated effectively from afar.

And, it can dance!

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