Here is another doorbell camera that lets you view your visitors on your iOS or Android device. The ZOSI 720p HD Doorbell Camera has motion detection, real-time two way audio, and infrared vision. It is waterproof.
You get dual power options for this doorbell camera: built-in rechargeable battery or using your existing doorbell wiring. The battery should lasts up to 8 months. The built-in PIR motion sensor has a range of up to 5 meters.