etc: simple button/coin cell battery holder

Needed a holder for leds inside of my acorns, super simple holder with
room for an led at the top and a wire hole on the side.

Intended to be printed from flexible material (TPE or TPU) for a snug
fit. Might work in rigid filament if slot_undersize is reduced, but no
guarantees.

diff --git a/etc/button-cell-holder.scad b/etc/button-cell-holder.scad
new file mode 100644 (file)
index 0000000..d948379
--- /dev/null
+++ b/etc/button-cell-holder.scad
@@ -0,0 +1,39 @@
+// Simple button cell battery holder
+// Created 2017 Clinton Ebadi <clinton@unknownlamer.org>
+
+// Released under the https://wiki.creativecommons.org/wiki/CC0
+// To the extent possible under law, Clinton Ebadi has waived all
+// copyright and related or neighboring rights to simple button cell
+// battery holder.
+
+// Defaults have no tolerance, should be printed using flexible
+// filament for a snug fit
+
+module holder (battery_d = 20, battery_h = 3.2, case_wall = 1.7, slot_undersize = 0.4, wire_d = 1.2, cover_pct = 0.4) {
+     battery_h = battery_h - slot_undersize;
+
+     case_d = battery_d + case_wall*2;
+     case_h = battery_h + case_wall*2;
+
+     %cylinder (d= battery_d, h = battery_h, center = true);
+
+     difference () {
+         cylinder (d = case_d, h = case_h, center = true);
+         cylinder (d= battery_d, h = battery_h, center = true);
+
+         // only cover cover_pct%
+         translate ([-case_d/2 + case_d*cover_pct, -case_d/2, -case_h/2 - 0.01]) cube ([case_d, case_d, case_h + 0.02]);
+
+         // slots for wires
+         hook_distance = -case_d/2 + case_d*cover_pct/2; // fixme: shitty name
+         for (z = [-battery_h/2, battery_h/2]) {
+//            #translate ([-case_d/2 - 0.01, 0, z]) rotate ([0, 90, 0]) cylinder (h = case_d/2 - hook_distance + 0.01, d = wire_d);
+              #translate ([-case_d/2 - 0.01, 0, z]) rotate ([0, 90, 0]) cylinder (h = case_d, d = wire_d);
+         }
+
+         // hole to bend wire up to hold in place
+         #translate ([hook_distance, 0, 0]) cylinder (h = case_h + 1, d = wire_d, center = true);
+     }
+}
+
+holder ($fs = 0.1, $fa = 1);