Binary sensors are gathering information about state of switches, contacts, pins, and alike. The return value of those sensors is usually digital (1/0). This means that those sensors knows only two states: 0/off/low/closed/false and 1/on/high/open/true.
Knowing that there are only two states allows Home Assistant to represent the sensor better in the frontend.
The display style of each entity can be modified in the customize section. The following device classes are supported for binary sensors:
- None: Generic on/off
- cold: On means cold (or too cold)
- connectivity: On means connection present, Off means no connection
- gas: CO, CO2, etc
- heat: On means hot (or too hot)
- light: Lightness threshold
- moisture: Specifically a wetness sensor
- motion: Motion sensor
- moving: On means moving, Off means stopped
- occupancy: On means occupied, Off means not occupied
- opening: Door, window, etc. On means open, Off means closed
- power: Power, over-current, etc
- safety: On means unsafe, Off means safe
- smoke: Smoke detector
- sound: On means sound detected, Off means no sound
- vibration: On means vibration detected, Off means no vibration
For analog sensors please check the component overview.