Yes, I run a computer based security system. It works great and it is very inexpensive.
First, go on eBay and purchase a DVR card for the computer you are going to use, make sure you get one that works on your operating system. 4 channel DVR card should be around $45. Next, if you have your small cameras they connect to the DVR card. If not, you can get those on eBay as well. You can get any type CDC, security camera you need. Infra-red for seeing in the dark, low light, black and white, color, lens configuration and any cables (all in one cables). Great camera that is IR w/ vari- focus & zoom should be around $100each.
The software loading and install of everything is very easy. You can record on the computer or to a hidden external hard drive just in case the computer grows legs during the night, you would still have or recordings for the police or BIG BAD JOHN. Some people post the beak-ins on YouTube and people let them know who it was.
With most of the systems you can connect other computers to it via a home/office network and view cameras and recordings from there. You can even view from your cellphone or over the Internet (secured access). You can still set some of them up to call you, email or text you when you are away. Again, for the money the are great. You should be able to get and install a 4 camera system for about $400 - $600 easy depending on what you get. Some of the complete systems that are offered tend to have very very cheap cameras.
If I did not have mine, I would have never gotten our dog a lady stole. Yes, I did say our DOG! Some nerve of people. I have watched the recordings of one of my trailers, a large tree in the yard and people just coming up to the house and barns looking around. It would just simply surprise you of things that happen when people see you're not at home.
After you catch people on video you have to really think how to deal with it. Should you contact the police if nothing was really done or should you start to make things more secure as in chain your trailers or only let the dog out when someone is outside. Things like that. Look at what they are looking at. Make corrections and if it happens again then contact the police.
Good luck and happy recording.
Keep us up to date on how it works out.