I am NXT 3-Point Bend Tester. Please Insert Girder.

Learning with visuals can be very helpful.  Learning with models made from NXT Mindstorms is just plain awesome, as [Rdsprm] demonstrates with this LEGO NXT 3-point bend tester that he built to introduce freshmen to flexural deflection and material properties. Specifically, it calculates Young’s modulus using the applied force of a spring and the beam’s deflection. [Rdsprm] provides a thorough explanation in the About section of the YouTube video linked above, but the reddit comments are definitely a value-add.

[Rdsprm] built this from the Mindstorms education base set (9797) and the education resource set (9648). Each contestant endures a 5-test battery and should produce the same result each time. The motor in the foreground sets the testing length of the beam, and the second motor pulls the spring down using a gearbox and chain. This method of deflection testing is unconventional, as [Rdsprm] explains. Usually, the beam is loaded incrementally, with deflection measured at each loading state.

Here, the beam is loaded continuously. Vertical deflection is measured with a light sensor that reads a bar code scale on the beam as it passes by. The spring position is calculated and used to determine the applied force. [Rdsprm] analysed the fluctuation in GNU Octave and has graphs of the light sensor readings and force-deflection.

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Trainable Robotic Arm

When [Robert] realized Adafruit is now selling analog feedback servos, he decided he just had to make a programmable robot arm that could be trained like the commercially available Baxter robot.
The neat thing with the analog feedback servos is it takes all the complexity out of training a robot.

All you have to do is put the robot in teach mode, physically move the robot’s joints to the positions you want, and save your program! Depending on your application, it certainly beats trying to work out the fun kinematics equations…

Anyway, the full guide available on Adrafuit’s learning system provides instructions on how to build your own arm from scratch (well, with a 3D printer) or how to replace the servos in a pre-made toy robotic arm you might already have sitting around. It’s very thorough and includes all the code you need for your Arduino too.

Stick around after the break to see how the robot works!

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DARPA Robotics Challenge Trials Wrap Up

The DARPA robotics challenge trials 2013 are have finished up. The big winner is Team Schaft, seen above preparing to drive in the vehicle trial. This isn’t the end of the line for DARPA’s robotics challenge – there is still one more major event ahead. The DARPA robotics finals will be held at the end of 2014. The tasks will be similar to what we saw today, however this time the team and robot’s communications will be intentionally degraded to simulate real world disaster situations. The teams today were competing for DARPA funding. Each of the top eight teams is eligible for, up to $1 million USD from DARPA. The teams not making the cut are still welcome to compete in the finals using other sources of funding.

The trials were broken up into 8 events. Door, Debris, Valve, Wall, Hose, Terrain, Ladder, and Vehicle. Each trial was further divided into 3 parts, each with one point available. If a robot completed the entire task with no human intervention it would earn a bonus point. With all bonuses, 32 points were available.

Team Schaft won the event with an incredible total of 27 points. In second place was Team IHMC (Institute for Human Machine Cognition) with 20 points. Team IMHC deserves special praise as they were using a DARPA provided Boston Dynamics Atlas Robot. Teams using Atlas only had a few short weeks to go from a completely software simulation to interacting with a real world robot. In third place was Carnegie Mellon University’s Team Tartan Rescue and their Chimp robot with 18 points.

The expo portion of the challenge was also exciting, with first responders and robotics researchers working together to understand the problems robots will face in real world disaster situations. Google’s recent acquisition — Boston Dynamics — was also on hand, running their WildCat and LS3 robots. The only real downside to the competition was the coverage provided by DARPA. The live stream left quite a bit to be desired.

The majority of videos on DARPA’s YouTube channel currently consist of 9-10 hour recordings of some of the event cameras. The wrap-up videos also contain very little information on how the robots actually performed during the trials. Hopefully as the days progress, more information and video will come out. For now, please share the timestamp and a description of your favorite part with your comments.

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Robot Battle for the Big Leagues: Valkyrie and the DARPA Challenge

Even though NASA’s Johnson Space Center’s impressive build for the upcoming DARPA Robotics Challenge is one of many entries, it has to be one of the coolest. The gang at IEEE Spectrum got a sneak peak of the robot dubbed “Valkyrie”, which at 1.9m and 125kg boasts 44 degrees of freedom while managing to look like a finished product ready to roll off the shelf. We can expect to see other custom robots at the challenge, but a number of teams will compete with a Boston Dynamics Atlas Robot, which we’ve covered a couple times this year.

A few readers are probably polishing their pitchforks in anticipation of shouting “Not a hack!” but before you do, take a look at the tasks for the robots in this challenge and consider how new this territory is. To that end, the NASA JSC crew seem to have prepared for resolving catastrophes, even if it means throwing together a solution. They’ve designed the limbs for quick removal and even reversibility: the arms are identical and only slight adjustments are required to turn a left arm into a right. Unlike the Atlas, which requires a tether, Valkyrie is battery-operated, and it can run for around an hour before someone needs to crack open the torso and swap in a new one, Iron Man film-style.

team was also determined to make Valkyrie seem more human, so they added a soft fabric layer to serve as a kind of clothing. According to IEEE Spectrum, it’s even getting custom made footwear from DC Shoes.There are some utilitarian compromises, though: Valkyrie has adopted a shortcut taken by time-constrained animators in many a cartoon, choosing three fingers per hand instead of four. Make sure you watch the video after the break for a closer look.

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Disk-O-Mat: A Photobooth For Records

A photo booth is a simple concept – drop in a coin and get a few pictures in a couple of minutes. That’s only a visual record, though. What if you wanted to record audio? Thus the disk-o-mat was born.
The disk-o-mat is one of [flo]‘s projects. In place of the miniaturized dark room found in a photo booth, [flo] put a record cutting setup. The 7″ records are polycarbonate sheets, each transferred to the turntable by a vacuum gripper. When the plastic disk is loaded, a stylus is set down on the disk and the record light goes on.

There isn’t a computer or any other digital means of saving audio and playing it back later. Everything is done just as how 45s – or more specifically, really old 78s – were cut; whatever goes into the microphone is cut directly into plastic. The disk-o-mat was originally built in 2009, and has traveled to a few venues. [flo] is working on speeding up the process and making the machine a bit more reliable. Still, an awesome build and an awesome concept.

Videos below.

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Will Dance For Bitcoin

It seems that Bitcoin is all over the news nowadays, but the Bitcoin Bot is probably the first robot that will dance for Bitcoins. [Ryan] at HeatSync Labs in Mesa, AZ, is a fan of the cryptocurrency, and decided to build something to accept it. He discovered that Coinbase, a popular hosted Bitcoin wallet service, has a callback API.

This causes Coinbase to fetch a specified URL any time a wallet receives a transaction, and provides information on the transaction in the request. A Python script handles these requests and updates a running count of the BTC balance sent to the robot’s wallet. On the hardware side, an Arduino with an Ethernet Shield checks the balance. If it has changed, it calls the dance function and the luau girl dances. The robot sits in the window of the hackerspace, so anyone passing by can read about Bitcoin and make a donation. The source code is on Github, and a video follows after the break.

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Incredible Automatic Zen Table

Most people think of Zen as a state of relaxation, and this invention can certainly provide that.  Essentially, the Zen Table uses a robot to “rake” the sand and create spectacular patterns.  Watching the Zen table in action is not only mesmerizing to watch, but also a superb engineering design.  It’s spendy, but would be an incredible addition to an office lobby or restaurant.

The bottom portion of the table holds the robotics and electronics that sculpt the images in the “sand.”  The sand is actually microscopic silicone beads under a glass tabletop of tempered glass.  Buyers can even opt for a 3G modem installation that will allow for receiving software updates and even operate the table from your smartphone.  Check out the full details.

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The Most Challenging Ping Pong Table Ever

Everyone has probably played a few games of Ping Pong in their day, but how many people have played on a table like this beast?  It moves while you play!  With a push of an arcade-type button, the table tilts left or right, changing the trajectory of the ball and making it harder to return the volley. The movement is provided by pneumatic actuators mounted under the table.

 As though that didn’t make it hard enough, players can push one of the buttons and “flash-bang” their opponent.  Super bright lights are mounted under the translucent table to temporarily blind your opponent.  The table can also be set to rock back and forth continuously, making it equally difficult for both players.  Polish up your skills and get your paddle out! Read up the complete details about the project.

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Large Pond + Zipline + Wakeboard = Awesome!

Here’s a dream come true for all you wakeboarding fans: ride all day without a boat, fumes, or gasoline. These two guys used a zipline attached to towers set at each side of a large private pond to make it happen. Check it out:

The towers are 140 yards apart which allows for a 120-yard wakeboarding run. The line is computer controlled through a laptop which reads and controls the speed, position, and direction of the line (it can also be set for a predetermined number of ski runs back and forth).  All it needs is an operator on shore to push the ‘go’ button and the computer does the rest.   Check out more details on the project.

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Incredible Robotic Zen Garden using CNC & Magnets

People LOVE custom coffee tables: We’ve seen PCs built into them, a giant NES, compasses, circuit boards, you name it.  This project, however, is arguably the most impressive of the bunch.  Essentially, it creates a pattern in the sand using modern electronics to emulate an actual Zen rock garden.  It uses a CNC-like machine combined with magnets beneath the sandy surface to move a small sphere through the sand.

The user uploads graphics to be “printed” on the table and edge detection software helps find the optimal method of drawing the image on the sand canvas.  Finally, the data is transmitted to the table via Bluetooth. Beneath the table is a CNC-like mechanism built with 3D printed gears and laser cut parts.  Full build instructions are not yet available, but some information is available on Kickstarter.

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iPad App Blends Virtual Warfare & Real-World Characters

This project is a basic proof of concept of creating a “physical” video game using real-world characters.  For this project, a tank and robot duke it out with the help of an Arduino, iPad, and wifi.  Essentially, when the tank’s targeting system is adjusted using the iPad app, the physical tank responds accordingly.  When the tank successfully hits its target, the robot’s indicator LED turns red and the iPad app reflects the successful strike.

Both the robot and tank are equipped with Arduino Wifi modules which interact with the iPad via a PHP webpage.  While it’s just a simple proof of concept for now, think of expanding this into something like a first-person quadrocopter war!  Just imagine your tablet as a window into your quadrocopter’s cockpit with buttons to fire at and ‘destroy’ your enemy.  Awesome stuff!  Check out the project’s build instructions to create your own real-world video game.

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How to: Build your own DIY “Animal” (Theo Jansen Strandbeest)

Theo Jansen demonstrated his famous “animal” inventions a few years ago at TED (video below). Essentially, these “animals” (dubbed Strandbeests) are driven entirely by the wind and use no electronics.

The way they move is absolutely fascinating, so one DIYer created his own miniature Strandbeest and shared the plans with the world.  Although the miniature version uses a small motor for locomotion, the unique walking mechanism is precisely replicated.

Each leg is comprised of 11 linkages which were designed using a special kinetic algorithm.  While the full-scale versions are built using PVC, the mini version can be built using threaded rods, a few nuts, and acrylic.  Check out the full build instructions, download the laser cutting plans, and create your own “animal” today!

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Compliant Robot Gripper Won’t Scramble Your Eggs

[Chiprobot] has created an amazing compliant gripper.  Designing robot hands (or end effectors) can be a perilous task. It is easy to give robots big, good, strong hands. Strong grippers have to be controlled by sensors. However, sensors can’t always be relied upon to ensure those hands don’t crush anything they touch. Hardware fails, software has bugs. Sometimes the best solution is a clever mechanical design, one which ensures a gripper will conform to the object it is gripping. We’ve seen “jamming” grippers before. (so named for their use of a granular substance which jams around the object being gripped).

[Chiprobot's] gripper is something entirely different. He designed his gripper in blender, and printed it out with his Ultimaker 3D printer. The material is flexible PLA. Three plastic “fingers” wrap around the object being gripped. The fingers are made up of two strips of printed plastic connected by wire linkages. The flexible plastic of the fingers create a leaf spring design. The fingers are attached to a linear actuator at the center point of the gripper. The linear actuator itself is another great hack.

[Chiprobot] created it from a servo and an empty glue stick.  As the linear actuator is pulled in, the fingers pull around  any object in their grip. The end result is a grip strong enough to hold an egg while shaking it, but not strong enough to break the egg. We would like to see the gripper gripping other objects, as eggs can be surprisingly strong. We’ve all seen the physics trick where squeezing an egg with bare hands doesn’t break it, yet squeezing an egg while wearing a ring causes it to crack much… like an egg.

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