[Ben Gravy] isn’t your average pro surfer. For one thing, he lives in New Jersey instead of someplace like Hawaii or Australia, and for another he became famous not for riding the largest waves but rather for riding the weirdest ones. He’s a novelty wave hunter, but some days even the obscure surf spots aren’t breaking. For that, he decided to build a surfboard that doesn’t need waves. (Video, embedded below the break.)
The surfboard that [Ben] used for this project isn’t typical either. It’s made out of foam without any fiberglass, which makes the board less expensive than a traditional surfboard. The propulsion was handled by an electric trolling motor and was hooked up to a deep cycle battery mounted in the center of the board in a waterproof box. The first prototype ended up sinking though, as most surfboards can’t support the weight of a single person on their own without waves even without all the equipment that he bolted to it.
After some reworking, [Ben] was able to realize his dream of riding a surfboard without any waves. It’s not fast, but the amount of excitement that he had proves that it works and could fool most of us. This hack has everything, too: a first prototype that didn’t work exactly right and was fixed with duct tape, electricity used in a semi-dangerous way, and solving a problem we didn’t know we had. We hope he builds a second, faster one as well.
Continue reading “Shred The Gnar Without Paddling For Waves”
How does a submarine talk to an airplane? It sounds like a bad joke but it’s actually a difficult engineering challenge.
Traditionally the submarine must surface or get shallow enough to deploy a communication buoy. That communication buoy uses the same type of radio technology as planes. But submarines often rely on acoustic transmissions via hydrophones which is fancy-talk for putting speakers and microphones in the water as transmitters and receivers. This is because water is no friend to radio signals, especially high frequencies. MIT is developing a system which bridges this watery gap and it relies on acoustic transmissions pointed at the water’s surface (PDF warning) and an airplane with high-precision radar which detects the oscillations of the water.
The complexity of the described setup is mind-boggling. Right now the proof of concept is over short distances and was tested in a water tank and a swimming pool but not in open water. The first thing that comes to mind is the interference caused by waves and by aerosols from wind/wave interactions. Those challenges are already in the minds of the research team. The system has been tested to work with waves of 8 cm (16 cm measured peak to trough) caused by swimmers in the pool. That may not sound like much, but it’s about 100,000 times the surface variations being measured by the millimeter wave radar in order to detect the hydrophone transmissions. Add to that the effects of Doppler shift from the movement of the plane and the sub and you have a signal processing challenge just waiting to be solved.
This setup is very interesting when pitched as a tool for researching aquatic life. The video below envisions that transmitters on the backs of sea turtles could send communications to aircraft overhead. We love seeing these kinds of forward-thinking ocean research projects, like our 2017 Hackaday prize winner which is an open source underwater glider. Oceanic studies over long distances have been very difficult but we’re beginning to see a lot of projects chipping away at that inaccessibility.
Continue reading “Submarine To Plane: Can You Hear Me Now? The Hydrophone Radar Connection”
Wave tanks are cool, but it’s likely you don’t have one sitting on your coffee table at home. They’re more likely something you’ve seen in a documentary about oil tankers or icebergs. That need no longer be the case – you can build yourself a wave generator at home!
This build comes to use from [TVMiller] who started by creating a small tank out of acrylic sheet. Servo-actuated paddles are then placed in the tank to generate the periodic motion in the water. Two servos are controlled by an Arduino, allowing a variety of simple and more complex waves to be created in the tank. [TVMiller] has graciously provided the code for the project on Hackaday.io. We’d love to see more detail behind the tank build itself, too – like how the edges were sealed, and how the paddles are hinged.
A wave machine might not be the first thing that comes to mind when doing science at home, but with today’s hardware, it’s remarkable how simple it is to create one. Bonus points if you scale this up to the pool in your backyard – make sure to hit the tip line when you do.
When you hear “gravity waves” or “sprites”, you’d think you would know what is being discussed. After all, those ripples in space-time that Einstein predicted would emanate from twin, colliding, black holes were recently observed to much fanfare. And who doesn’t love early 8-bit computer animations? So when we were browsing over at SpaceWeather we were shocked to find that we were wrong twice, in one photo (on the right). Continue reading “Two Words That Don’t Mean What You Think They Do”
This installment of Retrotechtacular looks at a video lecture that is much more substantive than the usual fare. [Dr. J.N. Shive] was a researcher at Bell Labs at a time when just about every technological breakthrough was coming from that singular collection of minds.
This video, called Similarities of Wave Behavior, was made to help bring students up to speed on the principles of waves. To aid in the experience he invented the apparatus seen in front of him. It’s called a Shive Wave Machine (in the prelude to the video they call it the Shive Wave Generator). Having not taken any physics classes at University we hadn’t seen one of these devices before. It uses a series of horizontal rods connected to each other with torsion wire. When you upset the balance of one of the rods the wire conducts that energy to its neighbors as an energy wave. This turns out to be a perfect representation of wave action whether it be mechanical, electrical, or acoustic. The 28-minute video after the break makes extensive use of the device, and explains concepts in a way that is easy to understand for just about anyone.
Continue reading “Retrotechtacular: Similarities Of Wave Behavior”
Reader [Eric] sent us a powerfully informative, yet super simple hack for the MindFlex toy. Don’t worry, it’s not another worthless shock ‘game’, And it’s using an actual interface instead of the built-in LEDs.
With two wires for the serial protocol, and an Arduino, you’ll be able to view “signal strength, attention, meditation, delta, theta, low alpha, high alpha, low beta, high beta, low gamma, high gamma” brainwaves. While it’s not medical grade, it’s a lot more intuitive than previous interfaces.
The original intent was for a system called MentalBlock, but we’re wondering what would you do with brainwave data?