Tech Series: Your Own WebCam Mystery Cache
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Tech Series: Your Own WebCam
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This installment of the tech series focuses on setting up a webcam.
Webcams are fun and entertaining. There is something voyeuristic
about watching your own webcam and seeing what it sees. This
installment we will discuss cameras, how to setup your webcam and
how to give the world access.
Setting up a webcam has three basic components. First you need a
camera. Once you have a camera, you will need software to snap shot
a moment in time as a computer image and finally you need some way
to share it with the world.
The Camera: Any PC camera will do. The higher resolution the camera
supports the clearer your picture be. There is a trade off though.
The higher the resolution, the bigger the picture and the longer it
takes to sent it to the web server and the longer it takes users to
download it. Generally speaking, a 640X480 resolution image is good
enough and can be compressed to between 30kb and 70kb (depending
again on your quality desires) which is are reasonable sizes. Most
of today’s cameras connect to your computer via USB. This
makes them pretty easy to use but limits placement and
availability. They only work when your computer is on and the
camera is connected and pointed where you want it. Another option
is a 802.11 WiFi camera. These can be placed anywhere you have an
electrical outlet and are not limited to your computer’s
location. The WiFi cameras have built in web servers and software
that can periodically upload pictures to a FTP server. I use a WiFi
camera for my webcam. Prices range from $10 a couple hundred bucks
depending on resolution and features. You can get camera that the
user can remotely control and move. My WiFI camera cost about $50
on sale is is mounted in a sheltered area outside pointed across my
front yard. USB cameras can be found a cheap as $10.
Getting a picture from your camera: A simple Google search for
“webcam software” returns 1,210,000 results (
http://bit.ly/Pb53a). You can add the keyword “free” to
limit the results to free webcam software. Many of these tools will
run on your computer and periodically take a picture from the web
cam and upload it to your web server service automatically. Some
will even generate a web page for you so all you have to do is
point it at your web server service and it will do everything.
Windows XP/Vista users can download the free “Webcam
Timershot” PowerToy from Microsoft to grab the current image
from the webcam. Depending on your skill level, you can setup your
computers task scheduler to automate running programs that get the
current image from your webcam and send it to your web server
service. If you use a WiFi webcam, they already contain the ability
to periodically send the current image to your web server service.
You just need to connect to the camera and set the appropriate
setting. For USB connected webcams I have used both YawCam
(http://www.yawcam.com) and TinCam (http://www.tincam.com). Of
course now, I don’t use either of the two since my webcam
does it all automatically. Also, some software will allow you to
modify the image with borders, date/time and other features. These
are all nice and can be fun too.
Sharing your webcam with the world: The most common way is to pick
any free service that offers both free webpages and ftp access that
permit webcam uploads (many do not). Here, you are on your own. You
might find a free or cheap hosting service that allows FTP access
for webcams but the half dozen I researched specifically forbid
webcam uploads in their terms of service. I run my own personal web
server. It is easy and free to do. Many computers already have a
web server. My Windows Vista Home Premium comes with a web server.
But it is real easy to install one of the many free, small, easy to
use web servers. I hear Abyss is good but I use Apache. Apache is
the granddaddy and worlds best web server. It installs in a snap
and is pretty much ready to use.
From here on, we will assume you have your webcam and software
already installed and have already selected the image size and
quality and frequency (I recommend 1 or 2 minutes) it takes images.
Now you are ready to send pictures somewhere. Now is a good time to
make a mental note of your choice in image file name. I’ll
use webcam.jpg for reference. You will need to substitute your own
image name where I use webcam.jpg.
If you find a suitable hosting service and plan to use it for your
webcam images, there are just a couple simple steps to having your
webcam online in just a few minutes. Simply configure your software
to ftp the current image to the web hosting account and path where
you want it stored there. For simplicity, don’t use a
separate folder just copy it to the home directory (usually just
don’t enter a path). Your pictures should start coming right
away. Skip the next paragraph to see how to test your image
uploads.
If you are using a personal web server all you need to do is point
your webcam software to save a copy of the image to the web server
directory. For example, in apache, the path is c:\apache\htdocs.
You can test the images (as described in the next paragraph) by
pointing your browser to http://localhost/webcam.jpg.
You can test everything by pointing your browser directly at your
images on your hosting service e.g.
http://mysite.myhostingservice.com/webcam.jpg (this is not a real
address, I just made it up here as an example). You should see your
image. Wait until a new picture is taken (based on your frequency
setting) and refresh your browser (reload, refresh, whatever it is
called on your browser. Both IE and Firefox support pressing
F5).
If you are using a WiFi webcam I’ll simply describe how mine
is setup. I have a local computer that runs apache and a free,
simple FTP server named Firezilla (if using a hosted service, they
already have a ftp server). I configured my WiFi camera to ftp
images every 20 seconds to my FTP server and save them in the
webcam image folder. That is all I needed to do. Every 20 seconds a
new image overwrites the old one..
More on my setup; After my initial webcam setup, I wanted to keep a
days worth of images which is about 4300 (3*60*24). Since my webcam
already allows me to add a sequence number to my webcam image, I
was able to tell it to start at 1 and end at 4400 where it starts
over. I then wrote a simple perl program that finds the newest
picture and copies it to webcam.jpg so the webpage always loads the
newest picture. Below is both an example of my perl program and the
generic web page I use to display the webcam image. Using Windows
task scheduler, I schedule the program to run every minute (the
minimum it supports). I put the perl program in a windows batch
file that is called by the scheduler. The batch file runs my perl
program, waits 15 seconds, repeats, waits 15 seconds and repeats
again. This way I get an image every 15 seconds.
My Perl One-liner to copy the newest image to webcam.jpg:
perl -e "$foo=`ls -rt webcam_* | tail -1`;system(\"cp $foo
webcam.jpg\");"
The batch file simple has:
perl -e "$foo=`ls -rt webcam_* | tail -1`;system(\"cp $foo
webcam.jpg\");"
sleep 15
perl -e "$foo=`ls -rt webcam_* | tail -1`;system(\"cp $foo
webcam.jpg\");"
sleep 15
perl -e "$foo=`ls -rt webcam_* | tail -1`;system(\"cp $foo
webcam.jpg\");”
Sample web page (all you would have to change is the src section of
the img tag):
This link is to the HTML code to display your own webcam. This is
what I use for my webcam. http://www.netbert.com/webcam/webcam_source.html
I hope you enjoyed this installment of the Tech Series. Good
Luck!
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