Binary Sensor

Binary sensors are similar to other sensors in that they monitor the states and conditions of different entities. Where binary sensors differ is they can only return one of two mutually exclusive values. For example, a binary sensor for a window may report a value of open or closed, a switch on or off, a condition true or false.

This either/or constraint is what makes these sensors binary. They are digital in nature, whereas analog sensors, like temperature and weight sensors, return a range of values.

Some binary sensors are created automatically when you add a device integration. For example, adding the ecobee integration will create a binary sensor to detect room occupancy. Other binary sensors can be created manually using the template integration or using an input boolean helper,

Device Class

Knowing a sensor is binary impacts how the sensor’s current state may be represented in Home Assistant’s UI (see Dashboards). Opposing states may be given different icons, colors, and value labels to highlight a particular state over the other. This is set by the binary sensor’s device class.

Here are a few examples of this representation in the UI:

Example of various device classes icons in on and off state. The on image in this example has state_color: true specified in the Entities card configuration to receive the icon coloring.

The full list of supported binary sensor device classes is below (note: these may also be modified in the customizing section).

• None: Generic on/off. This is the default and doesn’t need to be set.
• battery: on means low, off means normal
• battery_charging: on means charging, off means not charging
• carbon_monoxide: on means carbon monoxide detected, off no carbon monoxide (clear)
• cold: on means cold, off means normal
• connectivity: on means connected, off means disconnected
• door: on means open, off means closed
• garage_door: on means open, off means closed
• gas: on means gas detected, off means no gas (clear)
• heat: on means hot, off means normal
• light: on means light detected, off means no light
• lock: on means open (unlocked), off means closed (locked)
• moisture: on means moisture detected (wet), off means no moisture (dry)
• motion: on means motion detected, off means no motion (clear)
• moving: on means moving, off means not moving (stopped)
• occupancy: on means occupied (detected), off means not occupied (clear)
• opening: on means open, off means closed
• plug: on means device is plugged in, off means device is unplugged
• power: on means power detected, off means no power
• presence: on means home, off means away
• problem: on means problem detected, off means no problem (OK)
• running: on means running, off means not running
• safety: on means unsafe, off means safe
• smoke: on means smoke detected, off means no smoke (clear)
• sound: on means sound detected, off means no sound (clear)
• tamper: on means tampering detected, off means no tampering (clear)
• update: on means update available, off means up-to-date
• vibration: on means vibration detected, off means no vibration (clear)
• window: on means open, off means closed

For comparison, here are the device classes for analog sensors.