Resideo's Honeywell Home T9 Smart Thermostat comes with one temperature, humidity and motion sensor.

Here are all the ways to use smart sensors to kick off smart home automations, ensure family safety, and save money.

In the cases below, you can purchase a completed sensor and connect it to at least one major smart home hub: SmartThings, Google Home, Apple Homekit, Amazon Alexa or Home Assistant.

These tiny devices are smart-home helpers. They detect and alert you about motion, temperature, or open or closed doors and windows — and can tell other smart devices to act.

The Hue Outdoor Sensor is the first outdoor HomeKit sensor, and adds motion, temperature, and light sensors to automate the outside of your Apple-centric smart home.

Here’s how it works: Each Ecobee remote sensor appears twice in Apple’s new Home app on iOS 10, once as a temperature sensor and again as a motion detector.

The $249 Nest Learning Thermostat has a larger display, a better resolution and a far-field sensor for viewing time and temperature information from a distance. It works with Google Assistant and ...

With each sensor’s location carefully registered, this allows for setting up a dense, very low-power network of 433 MHz sensors for monitoring and home automation purposes.

There are absolutely motion sensors that are meant to work outside. Many smart home doorbells and security cameras have built-in motion sensors that can connect to your smart lights.

An outdoor motion sensor light offers security and illumination. Our home security expert recommends six models, including battery- and solar-powered lights.