Add binary sensor to MotionMount integration (#107659)

* Add binary sensor for `isMoving`

* Sort platforms alphabetically

* Update doc strings

homeassistant/components/motionmount/binary_sensor.py

@@ -0,0 +1,39 @@
+"""Support for MotionMount binary sensors."""
+import motionmount
+
+from homeassistant.components.binary_sensor import (
+    BinarySensorDeviceClass,
+    BinarySensorEntity,
+)
+from homeassistant.config_entries import ConfigEntry
+from homeassistant.core import HomeAssistant
+from homeassistant.helpers.entity_platform import AddEntitiesCallback
+
+from .const import DOMAIN
+from .entity import MotionMountEntity
+
+
+async def async_setup_entry(
+    hass: HomeAssistant, entry: ConfigEntry, async_add_entities: AddEntitiesCallback
+) -> None:
+    """Set up Vogel's MotionMount from a config entry."""
+    mm = hass.data[DOMAIN][entry.entry_id]
+
+    async_add_entities([MotionMountMovingSensor(mm, entry)])
+
+
+class MotionMountMovingSensor(MotionMountEntity, BinarySensorEntity):
+    """The moving sensor of a MotionMount."""
+
+    _attr_device_class = BinarySensorDeviceClass.MOVING
+    _attr_translation_key = "motionmount_is_moving"
+
+    def __init__(self, mm: motionmount.MotionMount, config_entry: ConfigEntry) -> None:
+        """Initialize moving binary sensor entity."""
+        super().__init__(mm, config_entry)
+        self._attr_unique_id = f"{self._base_unique_id}-moving"
+
+    @property
+    def is_on(self) -> bool:
+        """Get on status."""
+        return self.mm.is_moving or False