This tensegrity robot can crawl through your air ducts

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DuCTT is a lightweight robot that can navigate, inspect, repair and maybe one day clean air duct systems.

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With nearly 90 percent of our days spent indoors, wouldn’t you like to know that you’re not breathing a ridiculous amount of pollutants and debris? Truth be told, air conditioning and heating systems tend to be lead contributors to many air quality problems, often experienced by those working in buildings. The problem is that these ceiling ducts are often confined and otherwise inaccessible for inspection and repair, especially in the event of emergencies. And while there are unmanned, remote-controlled devices that can attempt to clean them with brushes, these gadgets are unable to access the remote parts of the HVAC units.

In an effort to solve this problem, researchers in the UCSD Robotics Lab have developed a duct-exploring robot based on the principles of tensegrity — a design paradigm which combines components under pure tension and compression to make mass efficient, accurately controllable structures.

What sets tensegrity robots apart is their characteristic lightweight and flexibility. DucTT consists of two linked tetrahedral structures, each containing a linear actuator, connected by a system of eight space-age cables similar to the tensioned frame of a pop-up tent. Inspired by a human’s own shoulder joints, a series of aluminum tubes and cables provide an extensive range of motion with a small number of actuators. Meanwhile, the batteries, electronics, motors and sensors are all embedded within these tubes to shield them from the gas or liquid that may be flowing within the duct during an inspection.

No different than an inchworm, DucTT makes its way through ducts in any orientation and can even accurately negotiating the intersection of two or more air pipes in deliberate fashion. The robot moves by first anchoring its top half, pulling its bottom half upward, and then anchoring its bottom half while the upper half extends again.

In terms of DucTT’s electronics, its paper reveals that a BeagleBone Black is tasked with handling high level control, while three Arduinos are used to perform position control of the six cable actuators. A single I2C bus enables communication between all the microcontrollers with the BeagleBone set as master. The robot is currently powered by eight 18650 lithium-ion cells, and since much of its bars are devoted to the batteries themselves, it can run for up to six hours continuously, untethered, on a single charge.

“Power and communication are fed between the tetrahedra through a single ribbon cable. Quadrature encoders are used to read motor position and conductive rubber cord stretch sensors are placed in parallel with the linear actuators to get rough length estimates. The Arduino also monitors the current being fed into the linear actuator to determine when adequate force has been exerted on the duct walls,” the team writes.

That all being said, DucTT isn’t equipped with any actual duct-cleaning gear at the moment, but it would presumably be easy to throw on some rotating brushes or a compressor of some sort. You can read all about the project here, or watch it in action below!

Interview: The NSA can’t crack this Arduino mixtape

As previously reported on Bits & Pieces, Maker David Huerta recently devised a DIY encrypted mixtape using an Atmel-based Arduino and a transparent acrylic case. The co-organizer of Art Hack Day and Cryptoparty had published his provocative piece of work to encourage the public to think a little bit more about privacy and what governments should or should not be allowed to do. As Huerta described, the device was created as a “soundtrack for the modern surveillance state” and is designed to be enjoyed only by those to whom he has given listening privileges.

Our friends at Arduino had the opportunity to catch up with the New York-based artist, where he went 1:1 with Zoe Romano. See their entire interview below:

Z: What makes you more uncomfortable about NSA actions which made you react and build this device?

D: The NSA’s mass surveillance encompasses a lot of programs which run counter to what I feel is a fundamental right to privacy. In the US Constitution there’s an expression of that in its fourth amendment. What the NSA is doing goes against the spirit of that much like petting a cat backwards; It’s the wrong direction to go towards and a cat/society will swipe its paw at the offender.

Z: Arduino community is always interested in understanding how things are made. Where we can find source code and technical specs to build one? It would be great if we all could share more practical knowledge on these topics.

D: The mixtape device is basically just an Arduino and Adafruit wave shield. The code to play each wave file on the SD card on a loop (when unencrypted) is right off their list of examples. I made one slight modification, which is to turn on a purple LED to indicate when it’s working. Purple is not an easy LED color to source, but it’s the global Pirate Party color and I wanted to give them subtle props for working towards a free and secure internet on the policy side of things.

I will at some point publish a way to do the encryption part of this using a Beaglebone Black and CryptoCape to make it a fully open hardware proof-of-concept, but in this case the SD card encryption was done off-device. I also plan on going through a full tutorial based on that at this year’s Open Hardware Summit in Rome.

Z: You said: “The NSA can read my stupid Facebook updates but without my consent it will never be able to listen to my… mix tape, even if it’s sitting right in front of them.” – What makes you believe that your encryption is strong enough?

D: The truth is that everyone sucks at information security, including myself, so no one can really make the claim something they’ve built is “NSA-proof.” Generally though, the less hardware and software you have, the less complexity and thus, opportunity for attack vectors or human errors there are. The playlist was kept offline, is not on the Arduino sketch, or anywhere in the hardware except encrypted in the SD card. The only place the audio existed aside from in the various sources I collected it from was on the hard drive of the PC I used to compose the mix tape, which has since been removed and stored offsite and offline. The encryption was also ran by a different machine, and one that I generally keep on my person. This goes beyond mass surveillance capabilities and into TAO/FBI “partyvan” surveillance; I can’t imagine an intelligence analyst is going to go to their very serious boss to explain that they need to expense a vehicle to go after some guy’s mix tape in a city where they won’t even be able to find a parking spot close enough to run a tempest attack from.

Z: Do you have the pictures of the inside showing the components and the circuits?

D: They’re not too exciting since its just the Arduino + Wave Shield, but I attached a photo of the unencrypted version (clear acrylic instead of red clear acrylic), which I’ll also be bringing with me to the Open Hardware Summit.

Interested in learning more? You can read all about the uncrackable mixtape on David Huerta’s original blog post here.