You could build a moat, get a few alligators and build a 40ft concrete wall around your home, or you could just get one of these.   

Grab a security CCTV camera including installation and a 36-month warranty from Safety Alarm Ltd, for only $119. 

Specifications: 

• 100% brand new.
• Weight: 322g
• Size:13.5 x 6.8 x 6.2cm
• Color: silver and white
• Vandal-proof
• Crisp, clear state of the art imaging
• Built-in infrared LED, may work under zero degree of illumination 
• Environment
• Powerful 1/3" Super CMOS color image sensor chip
• 30 (Φ0.5) LED IR illuminator view
• Indoor / Outdoor for Day / Night
• Aluminum Alloy Housing
• Applications: Office School home Lobby bar Store Hotel
• The bracket is included
• Image Sensor: 1/3" COLOR CMOS
• Number of Pixels: PAL:628 (H) x 582 (V)
• Horizontal Resolution: 380 TV Lines
• LED: 30 PCS
• Usable illumination: 0.000LUX(LED on)
• S/N Ratio: ≥48dB(AGC Off)
• System of Signal: PAL
• Electronic Shutter Time: Auto, PAL 1/50-100,000Sec
• White Balance: Auto
• Video Output: 1.0Vp-p,75Ω
• Power Source Supply: DC 12V±10% 1000 mA