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.

“Trataka” by Alessio Chierico is an interactive installation controlled by Arduino and based on a brain-computer interface. It was exhibited at Ars Electronica last week. When a visitor totally relaxes and focuses, the candle magically extinguishes:

Trataka is a Sanskrit term which means “to look” or “to gaze” and it refers to a meditation technique. This practice consists in concentrate the attention in a small object, or more commonly in a flame. In meditation, this technique is used to stimulate the ajna chakra: a point located in correspondence of the brain. According to the Hindu tradition, this chakra is one of the six main centers of vital energy, and it is considered as the eye of the intuition and the intellect.

This installation is composed by a brain-computer interface that detect the brain waves and defines parameters like the level of attention. Wearing this device, the user is invited to concentrate his attention on a flame placed in front of him. The level of attention detected by this system, controls an air flow located under the flame: higher level corresponds with a more intense air flow. The interaction process aims to the user engagement for increase his attention in order to put the flame out. This will happen when the highest level of attention is reached: the air flow become strong enough to extinguish the flame.