Throughout our day-to-day experiences, we come across or make use of many scientific principles which we might not be aware of, even if we immediately recognize them when they’re described. One such curiosity is that of caustics, which refers not only to corrosive substances, but can also refer to a behavior of light that can be observed when it passes through transparent objects. Holding up a glass to a light source will produce the effect, for example, and while this is certainly interesting, there are also ways of manipulating these patterns using lasers, which makes an aurora-like effect.
The first part of this project is finding a light source. LEDs proved to be too broad for good resolution, so [Neuromodulator] pulled the lasers out of some DVD drives for point sources. From there, the surface of the water he was using to generate the caustic patterns needed to be agitated, as the patterns don’t form when passing through a smooth surface. For this he used a small speaker and driver circuit which allows precise control of the ripples on the water.
The final part of the project was fixing the lasers to a special lens scavenged from a projector, and hooking everything up to the driver circuit for the lasers. From there, the caustic patterns can be produced and controlled, although [Neuromodulator] notes that the effects that this device has on film are quite different from the way the human eye and brain perceive them in real life. If you’re fascinated by the effect, even through the lens of the camera, there are other light-based art installations that might catch your eye as well.
Continue reading “Create an Aurora Of Your Own”
[Theo Jansen] has come up with an intriguing wind-powered strandbeest which races along the beach with surprising speed and grace. According to [Jansen], it “doesn’t have hinging joints like the classical strandbeests, so they don’t get sand in their joints and you don’t have to lubricate them.” It’s called UMINAMI, which appropriately means “ocean wave” in Japanese.
There are only videos of it in action to go on so far, but a lot can be gleaned from them. To make it easier to keep track of just a single leg, we’ve slowed things down and reddened one of them in the banner animation. Those legs seem to be providing a push but the forward motion is more likely supplied by the sails. The second video below shows it being pulled along by the type of strandbeest we’re all more used to seeing.
What follows is an analysis and best guess about how it works. Or you can just enjoy its graceful undulations in the videos below.
Continue reading “Theo Jansen Invents A Faster, Simpler, Wind-Powered Strandbeest”
Meticulous. Thorough. Exacting. These are all words we’d use to describe this video by [BrendaEM] about her Homemade 3D Optical Interference Scanner which can be seen after the break. The scanner uses 3D-printed parts and repurposed materials you might find lying around in your spare parts bin. An old optical drive tray acts to move the laser-wielding sled while a stripped-out webcam is an optical sensor. Links to relevant files such as 3D models and Arduino sketches will be found in the video’s author section.
The principle of operation is demonstrated with a water analog in the video at 2:00 with waves in a plastic container. By creating two small apertures between a light source and a sensor, it’s possible to measure the light waves which make it through. [BrendaEM] uses some powerful visualization software to convert her samples into 3D models which look really cool and simultaneously demonstrate the wave nature of light.
On the left side of her device are the control electronics which don’t need any special coatings since light won’t pass over this area. For the right side, where coherent light is measured, to borrow a Rolling Stones lyric: no colors anymore, I want them to turn black. Even the brass strips with apertures are chemically darkened.
Most of the laser hacks here use lasers rather than measure them, like this Laser Clock and a Laser Projector.
Continue reading “Interference Scanner with Clear Instructions”
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.
We humans are becoming more aware every day that we need to reduce our fossil fuel dependence and move to more renewable methods lest we make the earth a less-desirable place to live. The sun is here today, and it will be tomorrow, harness that energy is one solution. There are places that are commonly windy, we can harness that energy too. [Jonathan] and [Ellen] set out to harness that wind energy but not in the traditional wind-turbine way. Wind creates ocean waves and the pair set out to recover some of that wave energy. They built a proof of concept and they did it on a budget with a side of DIY-style, to boot!
The device consists of a raft, with magnets attached to a sheet metal ruler standing on end. As you would expect, this ruler is flexible and the mass of the magnets easily sways back and forth as waves pass. The magnets move through stationary wire coils and as they do, creating an electrical current in the coils. The output of the coils is AC, which is then rectified to pulsed DC using several diodes and smoothed even further by some capacitors. The two DC outputs are then connected in series to double the voltage to 5 with a max current of about 20mA.
For this experiment the generator powers a modified smoke alarm which keeps burglars away from a coral reef. But the team could see this powering lights on buoys or low-power sensors. What would you use it for?
These water droplets are not falling; they’re actually stuck in place. What we’re seeing is the effects of an acoustic levitator. The device was initially developed by NASA to simulate microgravity. Now it’s being used by the pharmaceutical industry do develop better drugs.
The two parts of the apparatus seen in the image above are both speakers. They put out a sound at about 22 kHz, which is beyond the human range of hearing. When precisely aligned they interfere with each other and create a standing wave. The droplets are trapped in the nodes of that wave.
So are these guys just playing around with the fancy lab equipment? Nope. The levitation is being used to evaporate water from a drug without the substance touching the sides of a container. This prevents the formation of crystals in the solution. But we like it for the novelty and would love to see someone put one of these together in their home workshop.
Don’t miss the mystical demo in the clip after the break.
Continue reading “Acoustic levitation of water droplets”
Here’s a fiery project which [Patrick] calls his Pyro Jam Can. It’s the simplest Rubens’ Tube build that we can think of. For the uninformed, a Rubens’ tube uses flammable gas to reveal wave forms passing through the supply vessel. In the past we’ve seen projects with multiple columns, which very clearly show a standing wave. But this version lacks the resolution for that, so the wave is seen as a modulated flame height.
You can see the propane feed tube coming into the can from the right. This keeps the gas flowing steadily, but a diaphram on the bottom of the can made of a latex balloon allows for modulations in flame height by pushing the gas through the aperture a bit faster than it is flowing. A speaker in the base bounces sound waves off of the diaphragm for the effect seen in the video clip after the break.
We wonder if the can will ever heat up enough to melt the balloon on the other end?
Continue reading “Single-column Rubens’ tube”