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”
With the fresh competition of Bing, we are reminded that search engines haven’t changed much since Google came along. Bing has made some nice advancements, like video previews, but still has a way to go to be truly different than Google. [Long]put together this prototype of a real time search system based off of Bings API. He was inspired by Google Wave which we hope to see soon. Wave is primarily for communication, redefining how email and messaging would work. We can’t help but think that Google probably has some cool stuff in the secret vaults for searching too. [Long]’s project seems like a decent start, but like the goodtimes.searchengine, we think it needs some work. What happened to the cool video previews? More importantly, why can’t we turn off the parental filter?