Electrostatic Headphones

December 4, 2005 by 18 Comments

electrostatic headphones

Most headphones and speakers use electromagnetic force to drive speaker coils. Electrostatic speakers use electrostatic force to modulate a diaphragm. Mylar is used as the diaphragm in these headphones. Two insulating rings sandwich the mylar and a perforated stator is placed on either side. Ideally these stators would be acoustically transparent, but sheets of metal with 2mm (or smaller) holes that make up at least 25% of the area work. Construction problems can arise from glue not sticking to the mylar and the mylar having not enough or too much tension. A special amp has to be built for the headphones to generate a 450V difference between the stators.

[thanks mrdelayer]

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The Magic Phone: Take Two

November 22, 2005 by 17 Comments

hadmagicphone

We’ve posted Part Two of the Magic Phone How-To over at Engadget. In this Installment, we show you the process behind creating the custom circuit that will live inside the rotary phone. This circuit is as small as possible by making it two-sided and by using surface mount components. Part One of the How-To covered number pad matrix decoding on just about any phone or number pad.

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Connecting DECT Phones Through Sound Cards For Asterisk

October 8, 2005 by 10 Comments

board

I couldn’t think of a better title. Here’s how it goes: [onno] wanted to convert a DECT phone for VOIP use. First he tried using transformers for the audio, but was unhappy with the noise and echo. He describes how to do a direct tap like [Christoffer]’s Skype phone, but includes all of the necessary measures to keep from frying your sound card. The main piece of this project is his hacked “chan_oss” driver for Asterisk. Using the driver, Asterisk is able to ring the DECT phone. It also detects whether the phone is off-hook by comparing the sound input to the known line noise level. The phone can dial using DTMF just like any standard phone.

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Thursday Nano Hacks: Making Black IPod Headphones

September 29, 2005 by 49 Comments

headphones13

We are starting a new feature for Thursdays here at Hack A Day: Thursday Nano Hacks. Our “hack” for the day is more of a mod out of necessity: Those ugly white headphones with a black iPod nano? Ew! Please come back next Thursday for a real iPod nano hack alrighty?

Scroll on for our little stroll through recoloring cables, and please read the conclusion. (Let’s just say that this hack is not exactly the stuff dreams are made of.)

What you will need:
– iPod headphones. They only come in white.
– PlastiDip in black (we used the dipping kind, but we recommend the spray aerosol kind in black)
– a tiny paintbrush you can throw out when you’re finished
– toothpicks
– stick or chopstick to stir the PlastiDip
– coathangers
– masking tape
– lots of time to waste

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How-To Build A Telephone Recording Circuit From An Old Modem

September 27, 2005 by 20 Comments

modemmatte2

We’ve posted our How-To for the week over at Engadget. Do you have an old modem lying around? Have you been dying to record some of your phone conversations for those podcasts or homebrewed movies or crazy flash animations you make? Wait no longer! Build yourself a little circuit to change the analog phone’s audio to regular line audio to record with your sound card. Remember that it is illegal in many places in the world to record phone conversations without both parties’ consent.

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Noise Cancelling Headphones

September 9, 2005 by 24 Comments

headphones

Here are plans for building a noise canceling headphone circuit. Noise cancellation works by placing microphones close to the ear and then playing the recorded sound out of phase causing destructive interference. Commercial headphones have the mics and power supplies built into the headphones. The page has some other fun suggestions for playing around with the stereo mic setup. If you’re looking for a cheaper route, there is this.

[thanks flybri and h-tech]

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Tv-b-gone Now B A Cellphone

April 28, 2005 by 33 Comments

TV B GONE CELL

Allright, we all should know about the handy device that came out awhile back called tv-b-gone and how it shuts off tv’s by holding down a button. problem is, it’s pretty easy to spot if you’re an awesome best buy security guard wearing that coveted yellow shirt, so you’re risking revealing yourself somewhat by using it. however, if you were to say, disguise it completely as a cellphone by totally redoing the whole thing, then you may be able to casually stroll by those TVs while “chatting on the cellie” and get out alive.

by alive we mean casually strolling out of best buy or an electronics store. very impressive idea here.

thanks [AJ]

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