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Arduino SRF08

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The speed of the sound in the dry air (20° C) is around 343 m/s. Send a short ultrasonic pulse at Frequency of 40Khz in the air, and try to listen to the echo. Of course you won’t hear anything (only a little click noise), but with an ultrasonic sensor the back pulse can be detected. If you know the time of the forth & back travel of the ultrasonic wave, you know the distance, divide the distance by two and you know the range from the ultrasonic sensor to the first obstacle in front of it.
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Fix locale issues in Mac OS X

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I faced a problem with locales in terminal on Mac OS X Lion. Midnight Commander didn’t want to display Cyrillic symbols in filenames and directories, on my remote media-Server I’ve been getting messages like “warning: setlocale: LC_CTYPE: cannot change locale (UTF-8)”. The solution is fairly simple – add these two lines to ~/.bash_profile (by default is seems to be missing, so create the file):

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ids:~ id$ cat .bash_profile 
 
export LC_CTYPE=en_US.UTF-8
export LC_ALL=en_US.UTF-8