feat: Add battery box item

nhf/touhou/houjuu_nue/electronics.py

@@ -206,6 +206,70 @@ class MountingBracket(Item):
         result.copyWorkplane(Cq.Workplane('XY')).tagPlane("conn_mid")
         return result
 
+@dataclass(frozen=True)
+class BatteryBox18650(Item):
+    """
+    A number of 18650 batteries in series
+    """
+    mass: float = 17.4 + 68.80 * 3
+    length: float = 75.70
+    width_base: float = 61.46 - 18.48 - 20.18 * 2
+    battery_dist: float = 20.18
+    height: float = 19.66
+    # space from bottom to battery begin
+    thickness: float = 1.66
+    battery_diam: float = 18.48
+    battery_height: float = 68.80
+    n_batteries: int = 3
+
+    def __post_init__(self):
+        assert 2 * self.thickness < min(self.length, self.height)
+
+    @property
+    def name(self) -> str:
+        return f"BatteryBox 18650*{self.n_batteries}"
+
+    @property
+    def role(self) -> Role:
+        return Role.ELECTRONIC
+
+    def generate(self) -> Cq.Workplane:
+        width = self.width_base + self.battery_dist * (self.n_batteries - 1) + self.battery_diam
+        return (
+            Cq.Workplane('XY')
+            .box(
+                length=self.length,
+                width=width,
+                height=self.height,
+                centered=(True, True, False),
+            )
+            .copyWorkplane(Cq.Workplane('XY', origin=(0, 0, self.thickness)))
+            .box(
+                length=self.length - self.thickness*2,
+                width=width - self.thickness*2,
+                height=self.height - self.thickness,
+                centered=(True, True, False),
+                combine='cut',
+            )
+            .copyWorkplane(Cq.Workplane('XY', origin=(-self.battery_height/2, 0, self.thickness + self.battery_diam/2)))
+            .rarray(
+                xSpacing=1,
+                ySpacing=self.battery_dist,
+                xCount=1,
+                yCount=self.n_batteries,
+                center=True,
+            )
+            .cylinder(
+                radius=self.battery_diam/2,
+                height=self.battery_height,
+                direct=(1, 0, 0),
+                centered=(True, True, False),
+                combine=True,
+            )
+        )
+
+
+
 
 LINEAR_ACTUATOR_50 = LinearActuator(
     mass=34.0,
@@ -254,6 +318,8 @@ LINEAR_ACTUATOR_BOLT = FlatHeadBolt(
 )
 LINEAR_ACTUATOR_BRACKET = MountingBracket()
 
+BATTERY_BOX = BatteryBox18650()
+
 @dataclass
 class Flexor:
     """