Measuring Magnetic Fields With A Robotic Arm

March 30, 2014 by Nick Conn 13 Comments

MagneticArm

Learning how magnets and magnetic fields work is one thing, but actually being able to measure and see a magnetic field is another thing entirely! [Stanley’s] latest project uses a magnetometer attached to a robotic arm with 3 degrees of freedom to measure magnetic fields.

Using servos and aluminium mounting hardware purchased from eBay, [Stanley] build a simple robot arm. He then hooked an HMC5883L magnetometer to the robotic arm. [Stanley] used an Atmega32u4 and the LUFA USB library to interface with this sensor since it has a high data rate. For those of you unfamiliar with LUFA, it is a Lightweight USB Framework for AVRs (formerly known as MyUSB). The results were plotted in MATLAB (Octave is free MATLAB alternative), a very powerful mathematical based scripting language. The plots almost perfectly match the field patterns learned in introductory classes on magnetism. Be sure to watching the robot arm take the measurements in the video after the break, it is very cool!

[Stanley] has graciously provided both the AVR code and the MATLAB script for his project at the end of his write-up. It would be very cool to see what other sensors could be used in this fashion! What other natural phenomena would be interesting to map in three dimensions?

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The Amazing Ping-Pong Robot Was Fake

March 28, 2014 by James Hobson 44 Comments

Well — you guys were right. As it turns out, it was actually a pair of animators who fooled the internet.

Not sure what we’re talking about? Last month, the [Kuka Robot Group] put out a highly polished video showing an industrial robot playing table tennis against the apparent world champion of the sport — it was extremely well done and entertaining to watch, but unfortunately… also fake. Weeks after the first [Kuka] video came out, someone named [Ulf Hoffmann] released another video, a small table tennis playing robot that looked almost feasible.

As some of our readers pointed out:

The movements seemed unnatural for the size of the servos and arm structure. ~ James

CGI. As others have pointed out, the shadow of the arm disappears when the robot is show from the side, even though they were added in the other shots. ~ Brandon

My cgi tip off was the cable under the table. It stretches instead of sliding around. ~ Aj

Notice it’s running Outlook Express and Internet Explorer – no self respecting hacker/maker would run those apps – lol. ~ vonskippy

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The Auto Parking Mecanum Robot

March 28, 2014 by Brian Benchoff 9 Comments

mecanum

A while back, Hackaday visited the Clark Magnet School in Glendale, California to sneak a peek on their STEM-focused curriculum, FIRST robotics club, awesome A/V classroom, and a shop that puts most hackerspaces to shame. We saw a few builds while we were there, but [Jack]’s auto parking mecanum robot was in a class by itself. It deserves its own Hackaday post, and now that [Jack] is on Hackaday Projects, he’s sharing all the details.

The most impressive aspect of [Jack]’s build is the mecanum wheels; the side plates for the wheels were designed by [Jack] himself and machined on his school’s Haas mill. When the plates came out of the mill they were flat, and each of the fifteen little tabs on the plates needed to be bent at a 45 degree angle. With a CNC jig and a lot of time on his hands, [Jack] bent the tabs for all eight plates.

In addition to the plates, the rollers were custom made from non-expandable polyurethane poured into a CNC milled mold. That’s a one-part mold; [Jack] needed to make sixty of these little parts, one at a time.

The electronics are built around an Arduino Mega communicating with a joystick via an XBee. [Jack] found the relays in the off-the-shelf motor board couldn’t handle the current, so he replaced them with much, much larger ones in a hack job we’d be proud to call our own handiwork. There’s also a little bit of code that allows this motorized cart to pull off the best parallel parking job anyone could ever wish for. You can see that and a few videos of the construction below.

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A Mini Op-Amp Based Line Following Robot

March 28, 2014 by Nick Conn 10 Comments

LineRobot

There’s no denying it. Super small robots are just cool. [Pinomelean] has posted an Instructable on how to create a mini line following robot using only analog circuitry. This would make a great demo project to show your friends and family what you’ve been up to.

Analog circuitry can be used instead of a microcontroller for many different applications, and this is one of them. The circuit consists of two op-amps that amplify the output of two phototransistors, which control each motor. This circuit is super simple yet very effective. The mechanical system is also quite cool and well thought out. To keep things simple, the motors drive the wheel treads, rather than directly through an axle. After the build was completed, the device needed to be calibrated by turning potentiometers that control the gain of each op-amp. Once everything is balanced, the robot runs great! See it in action after the break.

While not the smallest line follower we have seen, this robot is quite easy to reproduce. What little robots have you build lately? Send us a tip and let us know!

[via Embedded Lab]

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3 DOF Open Source Robot Arm Is Just The Beginning

March 27, 2014 by James Hobson 11 Comments

Arm3-v1

[Dan Royer] of Marginally Clever had a dream. A dream to build an open-source 6 DOF robot that anyone can make! To do so, he’s been learning robotics for the past two years, and has just finished the first step — he’s designed and built an open source 3 DOF palletizing robot!

He’s based this little guy off of the commercial ABB 460 palletizing robot, which is a tried and true industrial robot. It features all laser cut parts, a few nuts and bolts, some stepper motors and an Arduino UNO for the brain. He’s released all of the design files on Thingiverse and the firmware on GitHub — yet another project we’d like to build if only we had a laser cutter!

And don’t worry, the Arduino UNO is only being used for this first prototype — he’s already started writing code for the RUMBA (Reprap Universal Mega Board with Allegro-driver) controller for revision 2.

Stick around to see it write its first greeting with a marker — Hello World!

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Open Source Humanoid Robot Is Awesom-o

March 25, 2014 by Brian Benchoff 34 Comments

awesome-o

Coming from a lab in France is The Poppy Project, an open source humanoid robot that’s at least as cool as ASIMO.

Poppy was designed as an affordable bipedal robot for use in education and art. It’s a small robot at just over 80 cm in height, but it can walk, move its arms, rotate its torso, and interact with bags-of-meat humans with two cameras and an LCD face.

Although Poppy is open source, that doesn’t mean it’s exactly cheap; the current design includes twenty-one Robotis Dynamixels MX-28 robotic actuators, actually servos with magnetic encoders, temperature sensor, and an ARM microcontroller. These actuators sell for about $200, meaning Poppy contains $4000 in motors alone. The estimated cost of the entire robot is €7500-8000, or about $10,000 to $11,000 USD.

Still, there’s an incredible software platform that comes along with Poppy, and being open source any enterprising engineer can take up the project and attempt to bring the costs down. We’d love to take one out for a walk. Just get rid of the hands. That’s too far down the uncanny valley for us. Video below.

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Soft Robotics, Silicone Rubber, And Amazing Castings

March 24, 2014 by Brian Benchoff 13 Comments

Most of the robotics projects we see around here are heavy, metallic machines that move with exacting precision with steppers, servos, motors, and electronics. [Matthew] is another breed of roboticist, and created a quadruped robot with no hard moving parts.

[Matthew] calls his creation the Glaucus, after the blue sea slug Glaucus atlanticus. Inside this silicone rubber blob are a series of voids, allowing compressed air to expand the legs, gently inching Glaucus across a table under manual or automatic control.

Even though no one seems to do it, making a few molds for casting on a 3D printer is actually pretty easy. [Matthew] is taking this technique to an extreme, though: First, a mold for the interior pressure bladders are printed, then a positive of this print made in silicone rubber. These silicone molds – four of them, for the left, right, top and bottom – are then filled with wax, and the wax parts reassembled inside the final ‘body’ mold. It’s an amazing amount of work to make just one of these soft robots, but once the molds and masters are made, [Matthew] can pop out a soft robot every few hours or so.

There’s a lot more info on Glaucus over on the official site for the build, and a somewhat simpler ‘compressed air and silicone rubber’ tentacle [Matthew] built showing off the mechanics. Video below.

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