The camera is the crucial component. Some factors to consider
1. If the camera and computer are within 15 feet they can be connected directly
with FireWire (IEEE 1394). Active repeater cables can be used to extend this
further. For longer distances an Ethernet or wireless link using Internet
Protocol (IP) would be best.
2. For good sensitivity under low light conditions a CCD (Charge Coupled Device)
sensor is required. CCD sensors also respond more rapidly to changes in light
levels so are better for recording video. Most cheap webcams use a CMOS sensor
which is less sensitive.
3. For sharp images auto-focusing would be of benefit. Fixed focus webcams
intended for short range use are unlikely to provide quality images from 15
4. If the camera is to be mounted outside it will either need to be design for
external use or housed in a weatherproof enclosure.
5. Cameras are available with built-in web servers. However, to facilitate
recording and the triggering of alarms a host computer running webcam software
may be preferable.
A good low-cost CCD FireWire camera is Apple's iSight:
>Quote: "Featuring an autofocusing autoexposure F/2.8 lens
which captures high-quality pictures even in low lighting, iSight also includes
a dual-element microphone in its stylish compact aluminium body."
Another is Orange Micro's iBOT FireWire Web Cam:
For some IP cameras see Broadband Buyer:
and Transparent Communications Ltd:
Two good programs are TinCam (Windows, $19 shareware, 30-day free trial):
>Quote: "Monitor your home, your car, your office etc.
with TinCam. When TinCam detects motion it can grab a picture and send it to you
in an email if you're away from your computer."
and EvoCam (Mac OS X, $25 shareware, 15-day free trial):
>Quote: "EvoCam 3.5 introduces support for network cameras
and video servers, adds an access log and improves streaming performance for the
built-in web server, offers enhanced motion sensors, and features an entirely
rewritten user interface with live resizing and scrolling."
In addition to its web server, EvoCam also supports Zero Configuration
For a list of suitable cameras see 'EvoCam Supported Cameras':
>Quote: "In addition to any QuickTime-compatible camera or
video input device, EvoCam can be used to view, record or re-broadcast video
from network cameras. EvoCam can also control pan and tilt on some network
For a tutorial see 'HOW-TO: Turn your laptop into a home security system':
>Quote: "With almost any generic webcam and some
relatively cheap software, you can set up a motion-detecting security camera, a
periodically refreshed image of your home interior/exterior, or even a live
video feed direct from the excitement of your empty living room."
Also see 'Mini Media Mac: mini WebCam Security System':
>Quote: "The mini's small footprint and low cost make it
perfect for dedicated tasks. In this tutorial, we'll set up a wireless
As suggested in both those articles, Apple's Mac mini is a good choice for
running Evocam -- it's cheap to buy and only consumes around 20 watts of power: