Can I use my digital camera as a security camera when connected to my laptop?

I have tried this to try to get some photos of wildlife outside my house before. It is possible but you need some good lighting and your computer needs to be running all the time. You can use a software called Yawcam which is a motion activated webcam software. It can alert you when it senses movement in the camera. It does this by sensing the change in pixels:

http://www.teepeetech.com/security-software/motion-activated-webcam-security-software-vision-gs-pe-yawcam-and-others-14.html

Motion activated cameras are best because you don’t have to start recording until the system senses motion. If you record all the time, then your hard drive fills up.