commit ad3925d108c9af78ec55f4a78dd32953a779f891
Author: Paul Mathieu <paul@ponteilla.net>
Date:   Thu Aug 15 17:25:56 2024 +0200

    Initial commit: planetarium

diff --git a/planets.ipynb b/planets.ipynb
new file mode 100644
index 0000000..e6b2a17
--- /dev/null
+++ b/planets.ipynb
@@ -0,0 +1,314 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": 34,
+   "id": "afcfc049",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import re\n",
+    "\n",
+    "orbits = \"\"\"\n",
+    "Mercury: 88 days.\n",
+    "Venus: 225 days.\n",
+    "Earth: 365 days.\n",
+    "Mars: 687 days.\n",
+    "Jupiter: 4333 days.\n",
+    "Saturn: 10759 days.\n",
+    "Uranus: 30687 days.\n",
+    "Neptune: 60190 days.\n",
+    "\"\"\".splitlines()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 36,
+   "id": "c0665887",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "ratios = [int((re.findall(r'\\d+', x)[0:1] or [0])[0])/88 for x in orbits][1:]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 39,
+   "id": "56eb1e3f",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[1.0,\n",
+       " 6.307132459970888,\n",
+       " 15.660844250363901,\n",
+       " 44.66812227074236,\n",
+       " 87.61280931586609]"
+      ]
+     },
+     "execution_count": 39,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "[x / ratios[3] for x in ratios[3:]]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 41,
+   "id": "8401b303",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[1.0,\n",
+       " 1.5990053726670783,\n",
+       " 2.036596983383623,\n",
+       " 2.794068392473273,\n",
+       " 7.017024751533684,\n",
+       " 11.0571860632063,\n",
+       " 18.67393662543892,\n",
+       " 26.152959158138735]"
+      ]
+     },
+     "execution_count": 41,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "import math\n",
+    "[math.sqrt(x) for x in ratios]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 42,
+   "id": "85f986fc",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "dist = \"\"\"The distance from the Sun to Mercury is 0.39 AU, to Venus is 0.72 AU, to Earth is 1.00 AU, to Mars is 1.52 AU, to Jupiter is 5.20 AU, to Saturn is 9.54 AU, to Uranus is 19.22 AU, and to Neptune is 30.06 AU.\"\"\""
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 56,
+   "id": "7c321d05",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[5.875871902123325,\n",
+       " 15.072438995419457,\n",
+       " 20.0,\n",
+       " 26.280655022872775,\n",
+       " 44.729879383810726,\n",
+       " 53.83240228190293,\n",
+       " 64.3392710531322,\n",
+       " 71.04793076487243]"
+      ]
+     },
+     "execution_count": 56,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "[20 + 1.5 * math.log(float(x))*10 for x in re.findall(r'[0-9]+.\\d+', dist)]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 60,
+   "id": "36ce6b46",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "planets = [\n",
+    "    ('mercury', 1.0, 50),\n",
+    "    ('venus', 1.6, 130),\n",
+    "    ('earth', 2.0, 200),\n",
+    "    ('mars', 2.8, 270),\n",
+    "    ('jupiter', 7.0, 450),\n",
+    "    ('saturn', 11, 540),\n",
+    "    ('uranus', 18, 640),\n",
+    "    ('neptune', 26, 710),\n",
+    "]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 64,
+   "id": "6a36fcb8",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def b():\n",
+    "    prevp = 1.0\n",
+    "    for n, p, d in planets:\n",
+    "        yield p / prevp\n",
+    "        prevp = p\n",
+    "        \n",
+    "ratios = list(b())"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 89,
+   "id": "5f6e6b6b",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "scale = 5\n",
+    "\n",
+    "tooth_width = 0.8;\n",
+    "tooth_crop = 0.5;\n",
+    "tooth_thickness = 0.6;\n",
+    "\n",
+    "def gear_base_radius(n):\n",
+    "    perimeter = tooth_width * (1 + 0.8*(1-tooth_crop)) * n\n",
+    "    return perimeter / math.pi / 2;\n",
+    "\n",
+    "def gear_wheel_radius(n):\n",
+    "    return math.sqrt(gear_base_radius(n)**2 + (tooth_width/2)**2);\n",
+    "\n",
+    "def gear_radius(n):\n",
+    "    return scale * (gear_wheel_radius(n) + gear_base_radius(n) + tooth_crop)/2;\n",
+    "\n",
+    "def dcenter(n1, n2):\n",
+    "    return gear_radius(n1) + gear_radius(n2)\n",
+    "\n",
+    "def search():\n",
+    "    for n1 in range(11, 39):\n",
+    "        n2 = 50 - n1\n",
+    "        yield (n1, n2, n2 / n1, dcenter(n1, n2))\n",
+    "        \n",
+    "rr = list(search())"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 92,
+   "id": "b64daa46",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def found():\n",
+    "    for r in ratios:\n",
+    "        for n1, n2, tr, _ in rr:\n",
+    "            if tr < r:\n",
+    "                yield (n1, n2, r, tr)\n",
+    "                break"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 93,
+   "id": "c587ff67",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[(26, 24, 1.0, 0.9230769230769231),\n",
+       " (20, 30, 1.6, 1.5),\n",
+       " (23, 27, 1.25, 1.173913043478261),\n",
+       " (21, 29, 1.4, 1.380952380952381),\n",
+       " (15, 35, 2.5, 2.3333333333333335),\n",
+       " (20, 30, 1.5714285714285714, 1.5),\n",
+       " (19, 31, 1.6363636363636365, 1.631578947368421),\n",
+       " (21, 29, 1.4444444444444444, 1.380952380952381)]"
+      ]
+     },
+     "execution_count": 93,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "list(found())"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 81,
+   "id": "2d7d6f8b",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[(11, 39, 3.5454545454545454, 47.19308954151068),\n",
+       " (12, 38, 3.1666666666666665, 47.18558098978421),\n",
+       " (13, 37, 2.8461538461538463, 47.179354476011646),\n",
+       " (14, 36, 2.5714285714285716, 47.17415487784531),\n",
+       " (15, 35, 2.3333333333333335, 47.16979419516311),\n",
+       " (16, 34, 2.125, 47.166131477877656),\n",
+       " (17, 33, 1.9411764705882353, 47.16305960247725),\n",
+       " (18, 32, 1.7777777777777777, 47.16049634511566),\n",
+       " (19, 31, 1.631578947368421, 47.158378230688704),\n",
+       " (20, 30, 1.5, 47.15665622507779),\n",
+       " (21, 29, 1.380952380952381, 47.15529268372393),\n",
+       " (22, 28, 1.2727272727272727, 47.154259179645024),\n",
+       " (23, 27, 1.173913043478261, 47.15353496521375),\n",
+       " (24, 26, 1.0833333333333333, 47.15310590655676),\n",
+       " (25, 25, 1.0, 47.15296378588499),\n",
+       " (26, 24, 0.9230769230769231, 47.15310590655676),\n",
+       " (27, 23, 0.8518518518518519, 47.15353496521375),\n",
+       " (28, 22, 0.7857142857142857, 47.154259179645024),\n",
+       " (29, 21, 0.7241379310344828, 47.15529268372393),\n",
+       " (30, 20, 0.6666666666666666, 47.15665622507779),\n",
+       " (31, 19, 0.6129032258064516, 47.158378230688704),\n",
+       " (32, 18, 0.5625, 47.16049634511566),\n",
+       " (33, 17, 0.5151515151515151, 47.16305960247725),\n",
+       " (34, 16, 0.47058823529411764, 47.166131477877656),\n",
+       " (35, 15, 0.42857142857142855, 47.16979419516311),\n",
+       " (36, 14, 0.3888888888888889, 47.17415487784531),\n",
+       " (37, 13, 0.35135135135135137, 47.179354476011646),\n",
+       " (38, 12, 0.3157894736842105, 47.18558098978421)]"
+      ]
+     },
+     "execution_count": 81,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "8c2dca2a",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3 (ipykernel)",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.10.8"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}
diff --git a/planets.scad b/planets.scad
new file mode 100644
index 0000000..dae66c3
--- /dev/null
+++ b/planets.scad
@@ -0,0 +1,333 @@
+tooth_width = 0.8;
+tooth_crop = 0.5;
+tooth_thickness = 1.0;
+
+module tooth() {
+    width = tooth_width;
+    thickness = tooth_thickness;
+    crop = tooth_crop;
+    
+    points = [[0, width/2], [0, -width/2], [1, 0]];
+    intersection() {
+//        rotate([90, 0, 0])
+        linear_extrude(height=thickness, center=true)
+        polygon(points);
+        
+        cube([crop*2, width, thickness], center=true);
+    }
+}
+
+function gear_base_radius(n) = 
+    let (perimeter = tooth_width * (1 + 0.8*(1-tooth_crop)) * n)
+    perimeter / PI / 2;
+
+function gear_wheel_radius(n) =
+    sqrt(gear_base_radius(n)^2 + (tooth_width/2)^2);
+
+function gear_radius(n) =
+    (gear_wheel_radius(n)
+    + gear_base_radius(n) + tooth_crop)/2;
+
+module gear(n) {
+    radius = gear_base_radius(n);
+    wheel_radius = gear_wheel_radius(n);
+    thickness = tooth_thickness;
+    
+//    rotate([90, 0, 0])
+    linear_extrude(height=thickness, center=true)
+    circle(wheel_radius, $fn=50);
+    
+    for (i=[0:n-1]) {
+        angle=360 / n;
+        rotate([0, 0, i * angle])
+        translate([radius, 0, 0])
+        tooth();
+    }
+}
+
+gear_scale = 5;
+
+module final_gear(n) {
+    scale([gear_scale, gear_scale, gear_scale])
+    gear(n);
+}
+
+module orbit_ring(n1, n2) {
+    difference() {
+        union() {
+            cylinder(h=24, r=20, center=true);
+
+            translate([22, 0, 0])
+            rotate([0, 90, 0])
+            cylinder(h=10, r=5, center=true);
+            
+            translate([0, 0, 12])
+            final_gear(n=n1);
+            
+            translate([0, 0, -12])
+            final_gear(n=n2);
+        }
+        cylinder(h=100, r=14.7, center=true);
+    }
+}
+
+module orbit(length, orbit_order, n1, n2=25, planet_size=40) {
+//    orbit_length = 100;
+//    orbit_order = 20;
+   
+    orbit_length = length + 50;
+    
+    thickness = 2.0;
+    
+    rotate([0, 90, 0])
+    translate([0, 0, orbit_length/2])
+    cylinder(h=orbit_length, r=thickness/2, center=true, $fn=50);
+    
+    translate([orbit_length, 0, 0])
+    translate([0, 0, orbit_order/2])
+    cylinder(h=orbit_order, r=thickness/2, center=true, $fn=50);
+    
+    translate([orbit_length, 0, orbit_order+planet_size/2])
+    sphere(planet_size/2);
+    
+    orbit_ring(n1, n2);
+}
+
+module _sidegear_diff(r) {
+    difference() {
+        cylinder(h=200, r=r, center=true);
+        
+        translate([-2.5, 0, -110])
+        cube([5, 300, 300]);
+        
+        rotate([0, 0, 120])
+        translate([-2.5, 0, -110])
+        cube([5, 300, 300]);
+        
+        rotate([0, 0, 240])
+        translate([-2.5, 0, -110])
+        cube([5, 300, 300]);
+        
+        cylinder(h=210, r=8, center=true);
+    }
+    
+    cube([4, 4, 25], center=true);
+}
+
+module sidegear(n) {
+    difference() {
+        final_gear(n);
+        _sidegear_diff(n*0.75);
+    }
+}
+
+module flangebrace() {
+    translate([0, -30, 0])
+    cube([14.7, 5, 23], center=true);
+    
+    difference() {
+        union() {
+            translate([0, -12, 10])
+            cube([14.7, 39, 3], center=true);
+            
+            translate([0, -12, -10])
+            cube([14.7, 39, 3], center=true);
+        }
+        
+        cylinder(h=50, r=4, center=true);
+    }
+}
+
+module flange(offset) {
+    difference() {
+        cylinder(h=5, r=22, center=true);
+        
+        cylinder(h=10, r=14.4, center=true);
+    }
+    
+    difference() {
+        translate([offset, 0, 0])
+        cylinder(h=5, r=32, center=true);
+        
+        translate([offset, -32, 0])
+        cube([15, 10, 15], center=true);
+        
+        translate([offset, 0, 0])
+        _sidegear_diff(25);
+        
+        translate([offset, 0, 0])
+        cylinder(h=6, d=6.3, center=true);
+    }
+}
+
+module shaftend() {
+    difference() {
+        cylinder(h=3, r=3.9, center=true);
+        
+        cube([4, 4, 5], center=true);
+    }
+}
+
+module linkage(offset, n1=25, n2) {
+    color("pink")
+    translate([offset, 0, 0]) {
+        cube([4, 4, 25], center=true);
+        
+        translate([0, 0, 10])
+        shaftend();
+        
+        translate([0, 0, -10])
+        shaftend();
+        
+        translate([0, 0, 5])
+        sidegear(n=n1);
+        
+        translate([0, 0, -5])
+        sidegear(n=n2);
+    }
+    
+    color("white")
+    flange(offset);
+        
+    translate([offset, 0, 0])
+    flangebrace();
+}
+
+
+module sungear(n) {
+    difference() {
+        //orbit_ring(n1=25, n2=25);
+        final_gear(n);
+        cylinder(h=200, r=14.7, center=true);
+    }
+}
+
+
+
+module sunshaft() {
+    translate([0, 0, -180])
+    cylinder(h=400, r=15, center=true);
+    
+    translate([0, 0, -380])
+    cylinder(h=20, r=150, center=true);
+    
+    translate([0, 0, 45])
+    sphere(d=66);
+}
+
+/*
+
+inner gears:
+-----
+25: 9
+30: 2
+27: 1
+29: 2
+35: 1
+31: 1
+-----
+    16
+
+side gears:
+-----
+25: 7
+20: 2
+23: 1
+19: 1
+21: 2
+15: 1
+-----
+    14
+
+*/
+
+sh = 29;
+fh = 5;
+function sleevez(i) = -i * (sh + fh) - sh/2;
+function flangez(i) = sleevez(i) - 17;
+function orbitz(i) = 20 - sleevez(i);
+
+gear_offset = 48;
+
+orbit_ring(35, 25);
+
+
+//color("white") sunshaft();
+/*
+// mercury
+color("grey")
+translate([0, 0, sleevez(0)])
+orbit(50, orbitz(0), n1=25);
+
+translate([0, 0, flangez(0)])
+linkage(offset=gear_offset, n2=20);
+/*
+// venus
+color("yellow")
+translate([0, 0, sleevez(1)])
+orbit(130, orbitz(1), n1=30);
+
+translate([0, 0, flangez(1)])
+linkage(offset=gear_offset, n2=23);
+
+// earth
+color("#34a56f")
+translate([0, 0, sleevez(2)])
+orbit(200, orbitz(2), n1=27);
+
+translate([0, 0, flangez(2)])
+linkage(offset=gear_offset, n2=21);
+
+// mars
+color("red")
+translate([0, 0, sleevez(3)])
+orbit(270, orbitz(3), n1=29);
+
+translate([0, 0, flangez(3)])
+linkage(offset=50, n2=15);
+
+// jupiter
+color("orange")
+translate([0, 0, sleevez(4)])
+orbit(450, orbitz(4), n1=35);
+
+translate([0, 0, flangez(4)])
+linkage(offset=50, n2=20);
+
+// saturn
+color("purple")
+translate([0, 0, sleevez(5)])
+orbit(540, orbitz(5), n1=30);
+
+translate([0, 0, flangez(5)])
+linkage(offset=50, n2=19);
+
+// uranus
+color("#aaaaff")
+translate([0, 0, sleevez(6)])
+orbit(640, orbitz(6), n1=31);
+
+translate([0, 0, flangez(6)])
+linkage(offset=50, n2=21);
+
+// neptune
+color("#3333aa")
+translate([0, 0, sleevez(7)])
+orbit(710, orbitz(7), n1=29);
+
+/*
+*/
+
+/*
+gear0 = 7;
+gear1 = 7;
+
+spacing = 1.0;
+
+rotate([0, 0, $t*360])
+final_gear(gear0);
+
+translate([spacing + (gear_radius(gear0) + gear_radius(gear1)) * gear_scale, 0, 0])
+rotate([0, 0, -$t*360 * gear0 / gear1])
+final_gear(gear1);
+*/
\ No newline at end of file