Electro-permanent Magnets For Quadcopters

July 12, 2013 by Brian Benchoff 40 Comments

electromagnet

Imagine a quadcopter hovering above a payload – a can of beans, perhaps. The ‘copter descends onto the payload, activates an electromagnet, and flies away with a hobo’s dinner. Right now, this is a bit of an impossibility. A normal electromagnet that powerful would consume an amazing amount of power, something quads don’t usually have in abundance. With the OpenGrab project, the dream of a remote-controlled skycrane is within reach, thanks to some very clever applications of magnetics.

The tech behind the OpenGrab is an electro-permanent magnet, basically an electromagnet you can turn on and off, but doesn’t require any power to stay on. OpenGrab was heavily influenced by a PhD thesis aimed at using these devices for self-assembling buildings.

This project had a very successful Kickstarter campaign and has seen some great progress in the project. While beer doesn’t come in steel cans anymore, we can imagine a whole lot of really cool applications for this tech from infuriating electronic puzzles to some very cool remote sensing applications.

Web Based Automation Courtesy Of Raspberry Pi

July 12, 2013 by Mike Szczys 6 Comments

web-based-automation-via-rpi

This project is a great example of the Raspberry Pi’s ability to eclipse Arduino when it comes to interaction. [Fall Deaf] mentions that he used to use an Arduino board with an Ethernet shield to add extensible interactivity to his project. But this one, which is a home automation lamp project, uses a Raspberry Pi instead. The concepts end up being very similar. But the cost of the hardware is less and the coding work is arguably orders of magnitude easier.

Don’t get us wrong, the hardware is fundamentally different. When you move from Arduino to RPi you lose some I/O pins and the low level control of them isn’t quite as straight-forward. But you also don’t have to program the thing in C. The Linux kernel handles the low level control which means you can write your scripts using Python. Because Python is an interpreted language the testing and debugging is much faster — no need to flash new code, just run the script again.

This project used the RPi GPIO to drive a strip of LEDs which use the WS2801 protocol. The board includes a NIC which makes it a snap to use as a web server. The smart phone controls seen above are served up from the Pi using jQuery. Right now there’s a cord running out of the lamp. But there should be plenty of room to use a screw-in outlet adapter and to hide the RPi and its PSU inside.

The board still has enough juice to drive other automation features too, like acting as a web radio server.

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Ghostly Images Captured Only On Camera

July 12, 2013 by Brian Benchoff 13 Comments

is that a logo

A while back our good buddy [Ch00f] built a QR code clock, unreadable to both humans and computers. A human couldn’t read the clock because of the digital nature of a QR code, and because the clock used persistence of vision in driving the LEDs, a digital camera can’t capture all the pixels in the QR code at the same time. It’s a highly useless but impressive art piece. Now, [Ch00f] is turning that build on its head. He created a rudimentary display that is invisible to the human eye, but easily detected with a digital camera.

This build exploits a basic property of CMOS digital cameras – the rolling shutter. Because it takes time to get pixels off a modern digital image sensor, each picture is actual a composite of many different strips, each taken slightly out of sequence. You can see this for yourself by taking a picture of something rotating very fast with your camera phone; a picture of an airplane propeller will make the blades appear curved, or look like [Dr. Seuss] has an aeronautical engineering degree.

To create his display, [Ch00f] found a few inexpensive fiber optic lights. By aligning a few of these into columns and lighting them up in a precise sequence, he can exploit the rolling shutter and make an image appear. To the human eye, it looks like a solid wall of illuminated fiber optics.

As for how practical this build is, [Ch00f] says not much. For cell phone cameras, you’d need to have a very, very short exposure time for this to work. The only way to do that is to make this display unbelievably bright, or just put it out in the sun. We can’t see that being practical for any potential use case, but we’d be more than happy to see a large-scale attempt at displaying images with this technique.

Paper ROM

July 11, 2013 by Mike Szczys 39 Comments

This low-resolution memory device packs in just a few bytes of data. But it’s enough to spell out [Michael Kohn’s] name. He’s been experimenting with using paper discs for data storage.

His technique becomes immediately clear when you view the demo video below. The disc spins multiple times with the sensor arm reading one track. This gives the system the chance to measure the black band in order to get the data timing figured out. Once the outer track has been read the servo controlling the read head swings it to the next until all of the data is captured.

An Arduino is monitoring the QTR-1RC reflectance sensor which makes up the reading head. It uses the black band width in order to establish the size of an individual byte. Interestingly enough, the white parts of the disc do not contain data. Digital 0 is a black area 1/4 the width of the large black strip, and digital 1 is half as wide.

[Michael’s] set up the generator which makes the discs so that he can easily increase the resolution. The limiting factor is what the reading hardware is able to detect.

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How Do You Think This Quadcopter Feels?

July 11, 2013 by Mike Szczys 14 Comments

how-does-this-quadcopter-feel

You don’t speak the language of dogs and yet you can tell when one is angry, excited, or down in the dumps. How does that work, and can it be replicated by a robot? That’s the question which [Megha Sharma] set out to study as part of her graduate research at the University of Manitoba in Winnipeg.

The experiment starts by training the robot in a series of patterns meant to mimic emotion. How, you might ask? Apparently you hire an actor trained in Laban Movement. This is a method of describing and dealing with how the human body moves. It’s no surprise that the technique is included in the arsenal of some actors. The training phase uses stationary cameras (kind of like those acrobatic quadcopter projects) to record the device as it is moved by the actor.

Phase two of the experiment involves playing back the recorded motion with the quadcopter under its own power. A human test subject watches each performance and is asked to describe how the quadcopter feels. The surprising thing is that when asked they end up anthropomorphising the inanimate device even further; making up small stories about what the thing actually wants.

It’s an interesting way to approach the problem of the uncanny valley in robotic projects.

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Building Han Solo’s Blaster

July 11, 2013 by Brian Benchoff 3 Comments

It’s no secret that [Adam Savage] of Mythbusters fame is a huge fan of replica props, going so far as to make a Maltese Falcon out of Sculpey. This time, though, he’s doing one better for the nerds in the crowd by building the most accurate replica of Han Solo’s blaster ever.

Replica prop gurus already know [Lucas]’ original prop department based Han Solo’s BlasTech DL-44 blaster off an existing gun – the Mauser C96. Along with this gun, there were a few extra bits and bobs tacked onto this gun, including an old German scope, a flash hider from an aircraft machine gun, and even a few bits of metal from a model airplane.

All these extra parts and greeblies are very hard, if not impossible to find. Thankfully, there are a bunch of very skilled replica prop makers reproducing these parts for anyone who wants a very accurate DL-44 Blaster. [Norm] from Tested and [Adam] assembled these parts into an incredibly accurate replica of the ‘hero’ blaster – by far the most identifiable of Solo’s many iterations of blaster seen in Star Wars ep. IV.

Kebab Skewer Quadcopter

July 11, 2013 by Mike Szczys 13 Comments

kebab-skewer-quadcopter

Quadcopters are the epitome of high-tech hobby electronics. We’re quite used to seeing the frames built out of modern materials (carbon fiber, 3d printed, etc). But it’s pretty hard to beat the strength-to-weight ratio of kebab skewers. You heard us correctly. [Shiny Shez] built his quadcopter frame from kebab skewers.

You might want to get that Boy Scout Handbook out and brush up on your lashing skills. Lashing is a method of using rope (string in this case) to fasten together wooden sticks (bamboo kebab skewers). Once the lashed joints are precisely oriented [Shiny] applies a liberal coat of super glue to cement them in place.

He went the easy route when it comes to control hardware. You can get spare parts for the Husban X4, a commercially available quadcopter. Its main controller is used here. The single board controls the motors, monitors an IMU to keep the aircraft stable while in flight, and includes a wireless transceiver. On the receiving side [Shiny] uses an Arduino with a wireless module. This way he can control the quadcopter from his laptop, or go one step further and use an Android phone.