From fd31e966230c1e6776425fdb2c43ecfd50bb4a21 Mon Sep 17 00:00:00 2001
From: Roberto Alsina <roberto.alsina@gmail.com>
Date: Sat, 23 Jul 2022 11:57:47 -0300
Subject: [PATCH] Lower arm model

---
 monitor/lower_arm.py | 53 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 monitor/lower_arm.py

diff --git a/monitor/lower_arm.py b/monitor/lower_arm.py
new file mode 100644
index 0000000..cab6c99
--- /dev/null
+++ b/monitor/lower_arm.py
@@ -0,0 +1,53 @@
+# This is the arm from the tripod to the "elbow"
+
+import cadquery2 as cq
+from cadquery2 import exporters
+
+from hinge import hinge_gap, hinge_w
+
+# monitor hinge dimensions
+inner_monitor_hinge = 3.2 / 2
+outer_monitor_hinge = hinge_w / 2
+
+# tripod hinge dimensions
+inner_tripod_hinge = 7.5 / 2
+outer_tripod_hinge = 17.5 / 2
+tripod_hinge_width = 5.5
+
+
+monitor_hinge_shape = (
+    cq.Sketch().circle(outer_monitor_hinge).circle(inner_monitor_hinge, mode="s")
+)
+
+tripod_hinge_shape = (
+    cq.Sketch().circle(outer_tripod_hinge).circle(inner_tripod_hinge, mode="s")
+)
+
+arm_width = min(tripod_hinge_width, hinge_gap)
+arm_length = 150
+
+lower_arm = (
+    cq.Workplane("XY")
+    .rect(arm_width, arm_width)
+    .extrude(arm_length)
+    .edges("|Z or <Z or >Z")
+    .fillet(0.25)
+    .faces(">Y")
+    # Add hinge that connects to the monitor
+    .workplane(
+        centerOption="CenterOfBoundBox", offset=(hinge_gap - arm_width) / 2
+    )
+    .center(0, arm_length / 2 + (outer_monitor_hinge - inner_monitor_hinge))
+    .placeSketch(monitor_hinge_shape)
+    .extrude(-hinge_gap)
+    .center(0, -(arm_length + outer_tripod_hinge))
+    # Undo previous offset + new offset
+    .workplane(
+        offset=-(hinge_gap - arm_width - tripod_hinge_width + arm_width) / 2
+    )
+    # Add hinge that connects to the tripod
+    .placeSketch(tripod_hinge_shape)
+    .extrude(-tripod_hinge_width)
+)
+
+exporters.export(lower_arm, "lower_arm.stl")