Citizen science isn’t limited to the nerd community. When medical professionals get a crazy idea, their options include filling out endless paperwork for human consent forms and grant applications, or hacking something together themselves. When [David Wartinger] noticed that far too many of his patients passed kidney stones while on vacation, riding rollercoasters, he had to test it out.
Without the benefit of his own kidney stones, he did the next best thing: 3D printed a model kidney, collected some urine, and tossed a few stones that he’d collected from patients into the trap. Then he and a colleague rode Big Thunder Mountain Railroad sixty times, holding the model in a backpack at kidney height.
There are a number of ways to measure the speed of light. If you’ve got an oscilloscope and a few spare parts, you can build your own apparatus for just a few bucks. Don’t believe the “lies” that “they” tell you: measure it yourself!
The apparatus starts off with a very quickly pulsed IR LED, a lens, and a beam-splitter. One half of the beam takes a shortcut, and the other bounces off a mirror that is farther away. A simple op-amp circuit amplifies the resulting pulses after they are detected by a photodiode. The delay is measured on an oscilloscope, and the path difference measured with a tape measure.
If you happen to have a photomultiplier tube in your junk box, you can do away with the amplifier stage. Or if you have some really fast logic circuits, here’s another project that might interest you. But if you just want the most direct measurement we can think of that’s astoundingly accurate for something lashed up on breadboards, you can’t beat [Michael]’s lash-up.
Now it’s official. The particular website that was hit by a record-breaking distributed denial of service (DDOS) attack that we covered a few days ago was that of white-hat security journalist [Brian Krebs]: Krebs on Security.
During the DDOS attack, his site got 600 Gigabits per second of traffic. It didn’t involve amplification or reflection attacks, but rather a distributed network of zombie domestic appliances: routers, IP webcams, and digital video recorders (DVRs). All they did was create HTTP requests for his site, but there were well in excess of 100,000 of these bots.
In the end, [Krebs’] ISP, Akamai, had to drop him. He was getting pro bono service from them to start with, and while they’ve defended him against DDOS attacks in the past, it was costing them too much to continue in this case. An Akamai exec estimates it would have cost them millions to continue defending, and [Brian] doesn’t blame them. But when Akamai dropped the shields, his hosting provider would get slammed. [Krebs] told Akamai to redirect his domain to localhost and then he went dark.
If you wave your hand under the water’s surface, you get a pattern of ripples on the surface shortly thereafter. Now imagine working that backwards: you want to produce particular ripples on the surface, so how do you wiggle around the water molecules underneath?
That’s the project that a crew from the University of Navarre in Spain Max Planck Institute for Intelligent Systems undertook. Working backwards from the desired surface waves to the excitation underwater is “just” a matter of math and physics. The question is then how to produce the right, incredibly irregular, wavefront. The researchers’ answer was 3D printing.
The idea is that, by creating the desired ripples on the water’s surface, the researchers will be able to move things around. We’ve actually seen this done before in air by [mikeselectricstuff], and a more sophisticated version from the University of Navarre in Spain uses multiple ultrasonic transducers and enables researchers to move tiny objects around in mid-air.
What’s cool about the work done underwater by the Navarre Max Planck Institute group is that all they’re doing is printing out a 3D surface and wiggling it up and down to make the waves. The resulting surface wave patterns are limited in comparison to the active systems, but the apparatus is so much simpler that it ought to be useful for hackers with 3D printers. Let the era of novelty pond hacking begin!
[Marcel] was trying to shoehorn a few new parts into his trusty Nexus 5 phone. If you’ve ever opened one of these little marvels up, you know that there’s not much room under the hood to work with. Pulling out some unnecessary parts (like the headphone jack) buys some space, but then how to wire it all up?
[Marcel] needed a multi-wire connector that’s as thin as possible, but he wasn’t going to go the order-Kapton-flex route. Oh no! He built one himself from masking tape and the strands from a stranded wire. Watch the video how-to if that alone isn’t enough instruction.
There’s an especially large focus on 3D displays. Projecting onto screens, droplets of water, spinning objects, and even plasma combustion are covered. But so are the funny physical displays: flip-dots, pin-cushions, and even servo-driven “pixels”.
Flavien Théry’s La Porte
We really liked the section on LCDs with modified polarization layers — we’ve seen some cool hacks using that gimmick, but the art pieces he dredged up look even better. Makes us want to take a second look at that busted LCD screen in the basement.
We’re big fans of the bright and blinky, so it’s no surprise that [Blair] got a bunch of his examples from these very pages. And we’ve covered [Blair]’s work as well: both his Wobbulator and his “Color a Sound” projects. Hackaday: your one-stop-shop for freaky pixels.
[Blair]’s list looks pretty complete to us, but there’s always more out there. What oddball displays are missing? What’s the strangest or coolest display you’ve ever seen?
When the US Federal Aviation Administration (FAA) began requiring registration of quadcopters (“drones”) in the US, it took a number of hobbyists by surprise. After all, the FAA regulates real 747s, not model airplanes. [John Taylor], an RC hobbyist, has done what you do when faced with a law that you believe is unjust: he’s filed a lawsuit in the DC District Court, claiming that the FAA has overstepped their mandate.
Which one is the “aircraft”?
The lawsuit will hinge (as legal battles often do) on the interpretation of words. The FAA’s interpretation of quadcopters to be “aircraft” rather than toys is at the center of the dispute. Putting hobbyists into a catch-22, the FAA also requires recreational RC pilots to stay under a height of 400 feet, while requiring “aircraft” to stay above 500 feet except for emergencies, take-off, or landing. Which do they mean?
The editorial staff at Hackaday is divided about whether the FAA ruling makes no sense at all or is simply making hobbyists “sign their EULA“. This writer has spent enough time inside the Beltway to know an expanse of a mandate when he sees it, and no matter which body of the US government is to blame, regulating toy planes and helicopters as if they were commercial aircraft is an over-reach. Even if the intentions are benign, it’s a poorly thought-out ruling and should be revisited.
If you agree, you now have the chance to put your money where your mouth is. The DC Area Drone User Group is putting together a legal defense fund to push [Taylor]’s case. Nobody would be cynical enough to suggest that one can buy the legal system in the US, but, paraphrasing Diamond Dave, it sure as heck can buy a good enough lawyer to get the law changed.
