Automatic video recording of movements and notifications on your phone: Equipped with human body sensor and AI  human shape recognition technology ,  Xiaomi Smart Doorbell 3  monitors abnormal movements of your home entrance, and sends notifications to your smartphone as soon as it detects them. Smart Voice Changer Peace of Mind Even when someone rings the doorbell, you can see them in the doorway and communicate with them via your smartphone. Supports voice changer to protect your privacy. The new generation ultra-wide lens increases the vertical angle to 107 degrees, ensuring clear panoramic observation of the entire area in front of the door. Built-in 4 high-power 940nm infrared lights ensure clear images even in low or no light. Watch videos recorded in the past three days for free without purchasing a memory card or subscribing to cloud services, and check motion alert recordings anytime, anywhere. It only needs to be charged 3 times a year. Built-in high-capacity 5200mAh lithium battery further improves battery life, so there is no need for frequent charging and battery replacement.  The USB Type-C  charging port allows charging is faster and easier .