Add flight controller

Signed-off-by: Arnaud Morin <arnaud.gfpv@mailops.fr>

fc.py

@@ -0,0 +1,83 @@
+# @author Arnaud Morin <arnaud.gfpv@mailops.fr>
+# SPDX-License-Identifier: Apache-2.0
+#
+
+import cadquery as cq
+
+# A flight controller is not a material, it is a stack: two boards, their
+# spacers, and everything soldered to them.  This models only the envelope, as
+# one solid, so the density is FR4's -- bare PCB -- and the dense parts (FETs,
+# inductors, connectors) stand in for the air between the boards.  It lands the
+# block at about 12 g, which is what a real 25.5 mm FC plus 4-in-1 ESC weighs.
+PCB_DENSITY = 1.85e-3    # g/mm3, FR4
+
+
+def fc():
+
+    box = (cq.Workplane("XY")
+           .box(33, 33, 8, centered=(True, True, True))
+           .edges('Z')
+           .fillet(5)
+           )
+
+    # Remove extra for standoff
+    cut = (cq.Workplane("XY")
+           .pushPoints([
+               (25.5/2, 25.5/2),
+               (25.5/2, -25.5/2),
+               (-25.5/2, 25.5/2),
+               (-25.5/2, -25.5/2),
+           ])
+           .circle(7)
+           .extrude(5)
+           .translate((0,0,1.6/2))
+           )
+    box = box.cut(cut).cut(cut.mirror("XY"))
+
+    # Standoff
+    sta = (cq.Workplane("XY")
+           .pushPoints([
+               (25.5/2, 25.5/2),
+               (25.5/2, -25.5/2),
+               (-25.5/2, 25.5/2),
+               (-25.5/2, -25.5/2),
+           ])
+           .circle(2.5)
+           .extrude(5, both=True)
+           .translate((0,0,-2))
+           )
+    box = box.union(sta)
+
+    # holes in standoff
+    cut = (cq.Workplane("XY")
+           .pushPoints([
+               (25.5/2, 25.5/2),
+               (25.5/2, -25.5/2),
+               (-25.5/2, 25.5/2),
+               (-25.5/2, -25.5/2),
+           ])
+           .circle(1.2)
+           .extrude(10, both=True)
+           )
+    box = box.cut(cut)
+
+    # Make Z 0
+    box = box.translate((0,0,7))
+    return box
+
+
+result = fc()
+
+assert result.solids().size() == 1, "fc is not one solid"
+
+if "show_object" not in globals():          # running outside CQ-editor
+    def show_object(*args, **kwargs):
+        pass
+
+show_object(result)
+
+
+if __name__ == "__main__":
+
+    print("fc   %.2f g" % (result.val().Volume() * PCB_DENSITY))
+