Home Hacking Projects for Geeks

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Part I: Home Automation

Because a foreach loop is used, adding an additional camera is as easy as adding

an extra unit code to the @motion_ucs array, such as my @motion_ucs = ("1",

"2", "3", "4");

.

Within the foreach loop, the script waits before taking the next picture to

give the wireless camera a moment to warm up. Then, the script calls the

webcam tool to create a snapshot.

The script then uses the Image::Magick module to read the picture, analyze

the brightness, adjust the levels if necessary, and then output the picture to

the correct folder. Adjusting the levels of the picture dramatically improves

the quality of pictures taken in low light. You could certainly reduce the

size and quality of the picture before saving it to improve performance when

viewing the pictures remotely; however, IDS does a great job of doing this

on the fly, so you might as well save it with whatever (generally mediocre)

quality the cameras can produce.

Image::Magick can do many different things to improve image quality, so check

out the docs at http://www.imagemagick.org/www/perl.html.

If you find that the script is reporting an image brightness of greater than 1,

it’s probably because Image::Magick is reporting an image depth lower than

the image’s actual bit depth. After upgrading to a new version of the librar-

ies, I discovered that it was reporting an 8-bit image depth, but the image

was ...