YoLink LoRa Smart Door Sensor Starter Kit (one Hub + four Sensors) — 1/4 Mile Open-Air Range, Door-Left-Open Alerts, 5 Years Battery, SMS/Text, Email & App Alerts; Alexa, IFTTT, Home Assistant

What’s in the box: one YoLink Hub and four Door Sensors. Batteries come preinstalled and can last up to 5 years between changes. The system is expandable—supports 300+ devices from the YoLink product line and you can add additional hubs for large homes, condos, or multi-building properties. Notifications & monitoring: self-monitor to reduce costs and receive alarms and off-normal alerts via SMS/Text, Email and App notifications. See "Know Now!" for more details. A 24/7 cloud server continuously supervises devices for online presence, signal strength and battery level so the system is ready when you need it (Hub required for full functionality). Quick installation: scan each sensor’s QR code, assign a name, peel off the protective plastic from the pre-applied 3M brand mounting tape, then press the sensor and magnet onto the door and frame. Setup is fast and straightforward. Practical uses: place sensors on exterior doors and windows to "Protect Your Perimeter," control lighting, monitor fridge/freezer doors to prevent food loss, track activity in homes or businesses, and keep an eye on children or elderly loved ones. Sensors work well on liquor and medicine cabinets, gun safes, storage boxes and lockers. Door Left-Open reminders & audio alerts: configure the maximum open time you’ll accept and receive a Door Left-Open reminder when exceeded. Use the SpeakerHub (audio hub) to play tones or messages when a door is opened or left open too long. Local pairing and control: pair two or more devices to trigger actions locally. Even if the internet is out and the power is down, paired devices will still carry out their programmed actions. Pair door sensors to a Siren Alarm and disarm when needed, or control the siren with a SirenFob or FlexFob to build a custom security setup. Long-range performance: LoRa (Long-Range) technology operates in the 900 MHz band and delivers up to a 1/4 Mile open-air range, allowing placement where WiFi often can’t reach—basements, separate buildings, RVs and boats on your property. Requirements: an Android or Apple smartphone plus a wired ethernet port or a stable WiFi connection (2.4 GHz band, only).