by DIY Hacks and How Tos @ instructables.com:
The Clapper was a popular gadget in the 80’s and 90’s. It let you turn appliances on and off just by clapping. This can be pretty useful, but it has some limitations. First there is the problem of loud noises accidentally turning the lights off. Also, you can’t control multiple outlets independently of each other.
So I decided to make programmable version of the Clapper using an Arduino microcontroller. The Arduino lets you set codes for each outlet. This eliminates false triggering and lets you control multiple outlets independently. Your lamp could be turned on and off with one clapping pattern and your fan could be controlled with another pattern.
Sound Activated Outlet - [Link]
Focus a beam of sound at objects or into your head!
The Soundlazer directional audio project is the continuation of my first and very successful project here on Kickstarter. I developed the Soundlazer “Snap” during my quest to lower the cost of this amazing technology and give backers the opportunity to explore new possibilities in directional audio.
Parametric speakers like the Soundlazer are directional speaker systems. They use ultrasonic carrier waves to transmit audio to listeners in a focused beam of sound that acts like light from a laser. Generally speaking, only the person standing in front of a parametric speaker can hear the audio being transmitted. People to the sides of the directional audio source hear little or no sound.
Soundlazer “Snap” – The Directional Parametric Speaker - [Link]
A project has been designed around Holteks Ht8970 voice echo IC. Project can be used in various audio systems karaoke, toys, animatronics, show, display, exhibitions, and sound equipments.
The HT8970 is an echo/surround effect processor. It is designed for various audio systems including karaoke, television, sound equipments, etc. The chip consists of a built-in pre-amplifier, VCO or Voltage Control OSC, 20Kb SRAM, A/D and D/A converters as well as delay time control logic.
Voice Echo - [Link]
Researchers say they have captured the sound of a single moving atom.
Researchers at Columbia University and Sweden’s Chalmers University of Technology say that they have, for the first time, “captured” the sound a single atom makes when it moves around—a single “phonon,” as it were. It’s an achievement that could eventually be used as the basic science for new quantum computing devices.
Like everyone is taught in elementary school, anytime something moves or vibrates, it makes a sound. Scientists now know for sure that that principle extends down to the lowly atom.
“The sound amplitude, or strength, is very weak,” said Göran Johansson, a co-author of the paper published today in Science. “Basically, when you excite the atom, it creates a sound, one phonon at a time, according to theory. It’s the weakest possible sound possible at the frequency [that it vibrates].”
Scientists Have Captured the Sound One Atom Makes - [Link]
Clap switch/Sound-activated switch designed around op-amp, flip-flop and popular 555 IC. Switch avoids false triggering by using 2-clap sound. Clapping sound is received by a microphone, the microphone changes the sound wave to electrical wave which is further amplified by op-amp.
555 timer IC acts as mono-stable multi-vibrator then flip-flop changes the state of output relay on every two-clap sound. This can be used to turn ON/OFF lights and fans. Circuit activates upon two-clap sound and stays activated until another sound triggers the circuit.
Sound Activated Switch - [Link]
Viktor made a sound trigger for his DSLR camera:
Now that I can take pictures of lightning I decided that I also want to be able to trigger my camera with sound.
An op-amp filters and amplifies a microphone signal. The output is fed to a PIC microcontroller that triggers the flash when the sound reaches a certain level. The trigger sound level and shutter delay are set with a pot. [via]
Lil Bang – Sound trigger for cameras - [Link]
This circuit is a digital sound level meter with a LCD screen, capable of displaying 80 characters (4 rows with 20 characters on each). You can build this LCD display. It also provides more debugging information, such as the minimum and maximum analog-to-digital samples that were measured during each period. [via]
Digital Sound Level Meter - [Link]
This project makes a PIC microcontroller speak audio PCM sounds using PWM modulation! Pulse-code modulation (PCM) is a digital representation of an analog signal where the magnitude of the signal is sampled regularly at uniform intervals, then quantized to a series of symbols in a digital (usually binary) code . Pulse-width modulation (PWM) of a signal or power source involves the modulation of its duty cycle, to either convey information over a communications channel or control the amount of power sent to a load .
PIC sound player (PCM to PWM converter) - [Link]
Here is a Sound Localization Sensor that I made. I searched for days trying to find a commercial sound localization sensor or info on how to build one. Sound localization is what the human ear does when it determines that a sound is coming from the left or right. After talking to some gentlemen over at the Arduino forums, I realized that it wasn’t going to be as simple as I thought.
DIY Sound Localization Sensor – [Link]
Generating sound waves from PC sound card isn’t new ting. You can even download tons of software that allows generating various waves like sine, square, triangle waves on speaker output. Such sound generator gives quite good results that are acceptable in most situations like testing audio equipment or feeding complex signals in to your projects.
Generating complex sound waves on PC – [Link]