Marble Chooses Its Own Path

March 6, 2018 by Brian McEvoy 16 Comments

[Snille]’s motto is “If you can’t find it, make it and share it!” and we could not agree more. We wager that you won’t find his Roball sculpture on any shopping websites, so it follows that he made, and subsequently shared his dream. The sculpture has an undeniable elegance with black brackets holding brass rails all on top of a wooden platform painted white. He estimates this project took four-hundred hours to design and build and that is easy to believe.

Our first assumption was that there must be an Arduino reading the little red button which starts a sequence. A 3D-printed robot arm grasps a cat’s eye marble and randomly places it on a starting point where it invariably rolls to its ending point. The brains are actually a Pololu Mini Maestro 12-channel servo controller. The hack is using a non-uniform marble and an analog sensor at the pickup position to randomly select the next track.

If meticulously bending brass is your idea of a good time, he also has a video of a lengthier sculpture with less automation, but it’s bent brass porn. If marbles are more your speed, you know we love [Wintergatan] and his Incredible Marble Music Machine. If that doesn’t do it for you, you can eat it.

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The M1 NerfBot: When Prototypes Evolve

March 6, 2018 by James Hobson 7 Comments

What do you get when you cross a self-taught maker with an enthusiasm for all things Nerf? A mobile nerf gun platform capable of 15 darts per second. Obviously.

The M1 NerfBot built by [GrimSkippy] — posting in the ‘Let’s Make Robots’ community — is meant to be a constantly updating prototype as he progresses in his education. That being the case, the progress is evident; featuring two cameras — a webcam on the turret’s barrel, and another facing forward on the chassis, a trio of ultrasonic sensors, controlled by an Xbox 360 controller, and streaming video to a webpage hosted on the M1 itself, this is no mere beginner project.

Perhaps most compelling is how the M1 tracks its targets. The cameras send their feeds to the aforementioned webpage and — with a little reorganization — [GrimSkippy] accesses the the streams on an FPV headset-mounted smartphone. As he looks about, gyroscopic data from the phone is sent back to the M1, translating head movement into both turret and chassis cam movement. Check it out!

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The Sensor Array That Grew Into A Robot Cat

March 6, 2018 by Roger Cheng 32 Comments

Human brains evolved to pay extra attention to anything that resembles a face. (Scientific term: “facial pareidolia”) [Rongzhong Li] built a robot sensor array with multiple emitters and receivers augmenting a Raspberry Pi camera in the center. When he looked at his sensor array, he saw the face of a cat looking back at him. This started his years-long Petoi OpenCat project to build a feline-inspired body to go with the face.

While the name of the project signals [Rhongzhong]’s eventual intention, he has yet to release project details to the open-source community. But by reading his project page and scrutinizing his YouTube videos (a recent one is embedded below) we can decipher some details. Motion comes via hobby remote-control servos orchestrated by an Arduino. Higher-level functions such as awareness of environment and Alexa integration are handled by a Raspberry Pi 3.

The secret (for now) sauce are the mechanical parts that tie them all together. From impact-absorption spring integrated into the upper leg to how its wrists/ankles articulate. [Rongzhong] believes the current iteration is far too difficult to build and he wants to simplify construction before release. And while we don’t have much information on the software, the sensor array that started it all implies some level of sensor fusion capabilities.

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Behold The Giant Eye’s Orrery-Like Iris And Pupil Mechanism

March 4, 2018 by Donald Papp 13 Comments

This is an older project, but the electromechanical solution used to create this giant, staring eyeball is worth a peek. [Richard] and [Anton] needed a big, unblinking eyeball that could look in any direction and their solution even provides an adjustable pupil and iris size. Making the pupil dilate or contract on demand is a really nice feature, as well.

The huge fabric sphere is lit from the inside with a light bulb at the center, and the iris and pupil mechanism orbit the bulb like parts of an orrery. By keeping the bulb in the center and orbiting the blue gel (for the iris) and the opaque disk (for the pupil) around the bulb, the eye can appear to gaze in different directions. By adjusting the distance of the disks from the bulb, the size of the iris and pupil can be changed.

A camera system picks out objects (like people) and directs the eye to gaze at them. The system is clever, but the implementation is not perfect. As you can see in the short video embedded below, detection of a person walking by lags badly. Also, there are oscillations present in the motion of the iris and pupil. Still, as a mechanism it’s a beauty.

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This 3D-Printed Robotic Vacuum Sucks

February 24, 2018 by Tom Nardi 11 Comments

After you’ve taken a moment to ponder the turn of phrase used in the title, take a look at this scratch-built robotic vacuum created by [theking3737]. The entire body of the vacuum was 3D printed, and all of the internal electronics are off-the-shelf modular components. We can’t say how well it stacks up against the commercial equivalents from iRobot and the like, but it doesn’t look like it would be too hard to build one yourself to find out.

The body of this rather concerned-looking robot was printed on a DMS DP5 printer, which is a neat trick as it only has a build platform of 200 mm x 200 mm. Once all the pieces were printed, a 3D pen was used to “weld” the sections together. The final result looks a bit rough, but should give a bond that’s just as strong as the printed parts themselves.

The robot has four sets of ultrasonic range finders to detect walls and obstacles, though probably not in the positions you would expect. The right side of the robot has two sets of sensors, while the left side only gets one. We aren’t sure the reasoning behind the asymmetrical layout, but presumably the machine prefers making right turns.

Control is provided by an Arduino Mega and the ever-reliable HC-05 Bluetooth module. A companion Android application was written which allows configuring the robot without having to plug into the Arduino every time you want to tweak a setting.

We can’t say we’ve seen that many DIY robotic vacuums here at Hackaday, but we’ve certainly featured our fair share of hacks for the commercially available models.

TrackRobot Sports Welded Steel, Not Plastic

February 18, 2018 by Donald Papp 15 Comments

Don’t let the knee-high size of [Hrastovc]’s creation fool you. TrackRobot weighs in at a monstrous 60 kg (130 lbs) of steel, motors, and battery. It sports two 48V motors in a body and frame made from pieces of finger-jointed sheet steel, and can reach speeds of up to four meters per second with a runtime of up to an hour. The project’s link has more pictures as well as DXF files of the pieces used for the body.

Currently TrackRobot is remote-controlled, but one goal is to turn it into a semi-autonomous snow plow. You can see TrackRobot going through its first steps as well as testing out a plow prototype in the videos embedded below.

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Here’s Why Hoverboard Motors Might Belong In Robots

February 3, 2018 by Donald Papp 28 Comments

[madcowswe] starts by pointing out that the entire premise of ODrive (an open-source brushless motor driver board) is to make use of inexpensive brushless motors in industrial-type applications. This usually means using hobby electric aircraft motors, but robotic applications sometimes need more torque than those motors can provide. Adding a gearbox is one option, but there is another: so-called “hoverboard” motors are common and offer a frankly outstanding torque-to-price ratio.

A teardown showed that the necessary mechanical and electrical interfacing look to be worth a try, so prototyping has begun. These motors are really designed for spinning a tire on the ground instead of driving other loads, but [madcowswe] believes that by adding an encoder and the right fixtures, these motors could form the basis of an excellent robot arm. The ODrive project was a contender for the 2016 Hackaday Prize and we can’t wait to see where this ends up.