Talk To The (Robotic) Hand

Robotic hacker [Andrea Trufini] apparently likes choices. Not only does his robotic arm have six degrees of freedom, but it has a variety of ways he can control it. The arm’s software can accept commands through a programming language, via potentiometers, an infrared remote, or–the really interesting part–through spoken commands.

The videos don’t show too much of the build detail, but the arm is mainly constructed of laser cut plywood and uses an Arduino. Hopefully, we’ll see more particulars about the build soon but for now have a look at a similar project.

The software (myrobotlab) is on github and looks very impressive. The Java-based framework has a service-oriented architecture, with modules that support common processors (like the Arduino, Raspberry Pi, and Beagle Board) along with I/O devices (like motors, sound devices, and that Leap Motion controller you just had to buy). As you might expect from the demonstration found below, there are speech to text and text to speech services, too. Like a lot of open source projects, some of these services are more ready for prime time than others but that just means you can contribute your hacks back to the project.

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My Robot Army @ Maker Faire

For a few years now I’ve been developing an interactive army of delta robots. This ongoing project is fueled by my desire to control many mechanical extremities like an extension of my body (I’m assuming I’m not the only one who fantasizes about robots here).

IMG_1846Since my army doesn’t have a practical application… other than producing pretty light patterns and making the user feel extremely cool for a minute, I guess you’d call it art. In the past I’ve held a Kickstarter to fund the production of my art which I can now happily show at cool events with interesting people; Maker Faire being one of them.

Interactivity and Sprawling Crowds

Last year, for our debut at the big Bay Area Maker Faire, my collaborator, [Mark], and I displayed a smaller sampling of 30 robots for our installation. We also decided to create an interactive aspect for others to experience. After the end of our crowdfunding period last March, we had a little over a month to do any development before the big event, so our options were slim. The easy solution was to jam our delta code into the hand tracking demo which comes with the Xbox Kinect’s Open NI within Processing. This was cool enough to exhibit, but we hadn’t really anticipated how it would go over in an environment as densely packed as the dark room at Maker Faire.

We should have known better. Both of us were aware that there would be many, many children… all with micro hands to confuse and bewilder the Kinect, but we did it anyway. Our only resolve was to implement the feature that would force the Kinect to track one hand at a time, only after being waved at in a very particular fashion. After needing to explain this stipulation to every person who stopped by our booth over the course of the weekend, we decided never to use the Kinect for crowds ever again; lesson learned.

Delta Robots and DMX

Over the past year since that experience, we’ve tripled the size of the installation and brainstormed some better demo ideas. As of now, the robots are all individually addressable over an RS485 bus, and we use the DMX protocol over a CAT5 cable to send commands. If you aren’t familiar with it, DMX is used in show production to control stage lighting… to which there is a super neat and free application called QLC+ that allows you to effectively orchestrate the motion and color of many individual light units; perfect for our cause.

qlcDeltasFunctionally, each of the 84 delta robots in the installation believes that it is a stage light (robots with identity issues). We mapped the X and Y axis of the end effector to the existing pan and tilt values, and the z axis to the beam focus value. The RGB of the LED mounted in the end effector of each delta maps directly to the RGB value of the stage light.

By using the sliders in the QLC+ GUI, I could select groups of robots and create presets for position and color. This was great, someone like me who doesn’t really write a lot of code could whip up impressive choreography with little sweat. Additionally, the program comes with a nice visualizer, where you can layout virtual nodes and view your effects as you develop them.

This is the layout of our installation mapped in QLC+. The teal and purple sliders around each light represent pan and tilt (or in our case X and Y):

QLCdelta

Lighting control was an interesting solution. Having autonomous robots this year changed how people responded to them, as they were less like an army you’d command and more of a hypnotic field of glowing grass.

[Mark] and I are considering picking up some flex sensors and maybe playing with the Leap or an EEG headset as a means to reintroduce the interactive aspect. Bottom line, I have this cool new toy that I can’t wait to play with over the summer!

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Twisted String Actuators

[Travis] tells us about a neat actuator concept that’s as old as dirt. It’s capable of lifting 7kg when powered by a pager motor, and the only real component is a piece of string.

The concept behind the twisted string actuator, as it’s known to academia, is as simple as putting a motor on one end of a piece of string, tying the other end off to a load, and putting a few twists in the string. It’s an amazingly simple concept that has been known and used for thousands of years: ballistas and bow-string fire starters use the same theory.

Although the concept of a twisted string actuator is intuitively known by anyone over the age of six, there aren’t many studies and even fewer projects that use this extremely high gear ratio, low power, and very cheap form of linear motion. A study from 2012 (PDF) put some empirical data behind this simple device. The takeaway from this study is that tension on the string doesn’t matter, and more strands or larger diameter strands means the actuator shrinks with a fewer number of turns. Fewer strands and smaller diameter strands take more turns to shrink to the same length.

As for useful applications of these twisted string actuators, there are a few projects that have used these systems in anthropomorphic hands and elbows. No surprise there, really; strings don’t take up much space, and they work just like muscles and tendons do in the human body.

Thanks [ar0cketman] for the link.

Hacklet 30 – Robot Arm Projects

Robot arms – they do everything from moving silicon wafers to welding cars. Many a hacker has dreamt of having their own robot arm to serve them beer help them build projects. This week’s Hacklet features some of the best robot arm projects on Hackaday.io!

robotarm1We start with [4ndreas] who is building this incredible 3D Printable Robot Arm. Inspired by large industrial robots, [4ndreas] has given us an entirely 3D printable design. [4ndreas’] 3D design experience really shows here. This arm looks like it just finished work at a local assembly line! The arm is BIG too – printing the parts took him about a week, and used around 1.2kg of ABS filament! [4ndreas] has recently split the project off into two halves: his blue arm is driven by stepper motors, while the orange arm is a DC motor affair. Both of the arms can use his awesome gripper design. Check out the project page for videos of the arm in action!

6dofarmNext up is [Dan Royer] and his 6DOF Robot Arm. [Dan’s] didn’t want to spend upwards of $10,000 on an industrial arm, so he built his own from wood, plastic, and easily obtainable parts. As the name implies, the arm has 6 degrees of freedom. The electronics consist of beefy NEMA 17 stepper motors and a RUMBA controller, which was originally designed for 3D printers. Dan even created some novel encoder mounts. Each joint has an encoder, which will allow the robot to run as a closed loop system. [Dan] originally entered this arm in The Hackaday Prize 2014. While it didn’t get him to space, we’re betting it will be able to get him a soda!

MeArm

No robot arm Hacklet would be complete without featuring [ben.phenoptix] and the awesome MeArm. MeArm is a pocket-sized robot arm which uses tiny 9 gram servos for locomotion. It’s built from laser cut acrylic and standard hardware. We loved the MeArm so much that we featured it as one of the challenges in our Embedded Hardware Workshop in Munich. More recently, [Ben] and MeArm have had a great run on Kickstarter. Let’s hope those arms are good at stuffing, addressing, and mailing out packages!

 

owiFinally we have [Kenji Larsen] with Reactron material transporter. The material transporter is just a small part of [Kenji’s] larger Reactron project. It started with an OWI-535 robot arm. The OWI is really a toy – a plastic kit which builds an open loop DC motor driven arm. [Kenji] has put some serious time into modifying his particular arm. He experimented with molding his own potentiometers for each joint before settling on a printed circuit board based design. Once the new system was in place, he found that his resistors were good for about 10,000 cycles. Not bad for a modified toy!

There are quite a few robot arm projects we weren’t able to cover in this edition of The Hacklet – you can check them all out on our brand new Robot Arm Projects List!

That’s it for this Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Gift Your Next Robot With the Brain of a Roundworm

A group of developers called [OpenWorm] have mapped the 302 neurons of the Caenorhabditis elegans species of roundworm and created a virtual neural network that can be used to solve all the types of problems a worm might encounter. Which, when you think about it, aren’t much different from those a floor-crawling robots would be confronted with.

wormy

In a demo video released by one of the projects founders, [Timothy Busbice], their network is used to control a small Lego-rover equipped with a forward sonar sensor. The robot is able to stop before it hits a wall and determine an appropriate response, which may be to stop, back up, or turn. This is all pretty fantastic when you compare these 302 neural connections to any code you’ve ever written to accomplish the same task! It might be a much more complex route to the same outcome, but its uniquely organic… which makes watching the little Lego-bot fascinating; its stumbling around even looks more like thinking than executing.

I feel obligated to bring up the implications of this project. Since we’re all thinking about it now, let’s all imagine the human brain similarly mapped and able to simulate complex thought processes. If we can pull this off one day, not only will we learn a lot more about how our squishy grey hard drives process information, artificial intelligence will also improve by leaps and bounds. An effort to do this is already in effect, called the connectome project, however since there are a few more connections to map than with the c. elegans’ brain, it’s a feat that is still underway.

The project is called “open”worm, which of course means you can download the code from their website and potentially dabble in neuro-robotics yourself. If you do, we want to hear about your wormy brain bot.

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Mikey, the Robot That Charges Itself

 

mikey-the-robot

Mikey is [Mike’s] autonomous robot. Like any good father, he’s given the robot his name. Mikey is an Arduino based robot, which uses a Pixy camera for vision.

[Mike] started with a common 4WD robot platform. He added an Arduino Uno, a motor controller, and a Pixy. The Pixy sends directions to the Arduino via a serial link. Mikey’s original task was driving around and finding frogs on the floor. Since then, [Mike] has found a higher calling for Mikey: self charging.

One of the most basic features of life is eating. In the case of autonomous robots, that means self charging. [Mike] gave Mikey the ability to self charge by training the Pixy to detect a green square. The green square identifies Mikey’s charging station. Probes mounted on 3D printed brackets hold the positive leads while springs on the base of the station make contact with conductive tape on Mikey’s belly. Once the circuit is complete, Mike stops moving and starts charging.

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Roving Hexapod Poops Out 3D Prints

[Jia Wu, Mary Sek, and Jeff Maeshiro], students  at the California College of the Arts (CCA) in San Francisco, took on the task of developing a walking 3D printer. The result is Geoweaver, a hexapod robot with a glue gun extruder system. Hackaday has seen walking CNC machines before, but not a 3D printer. Geoweaver uses two servos on each of its six legs to traverse the land. The team was able to program several gaits into the robot, allowing it to traverse uneven terrain. Walking is hard enough on its own, but Geoweaver also uses a glue gun based extruder to make 3D prints. The extruder head uses two servos to swing in a hemispherical arc. The arc is mapped in software to a flat plain plane, allowing the robot to drop a dollop of glue exactly where it is programmed to. Geoweaver doesn’t include much in the way of on board processing – an Arduino Uno is used to drive the 15 servos. Those servos coupled with a glue gun style heater pull quite a bit of power, which has earned Geoweaver nicknames such as Servo Killer, Eater of Shields, Melter of Wires, and Destroyer of Regulators.

Geoweaver’s prints may not be much to look at yet, however the important thing to remember is that one of the future visions for this robot is to print on a planetary scale. Geoweaver currently uses reacTIVision to provide computer control via an “eye in the sky”. ReacTIVision tracks a fiducial marker on the robot, and applies it to a topographical map of the terrain. This allows Geoweaver to change its height and print parameters depending on the flatness of the ground it is printing on. On a scaled up Geoweaver, reacTIVision would be replaced by GPS or a similar satellite based navigation system.  Most of the software used in Geoweaver is opensource, including Grasshopper and Firefly, written by the team’s professor, [Jason Kelly Johnson]. The exception is Rhino 5. We would love to see an option for a free or open source alternative to laying out ~$1000 USD in software for our own Geoweaver.

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