Center flex

battery-case-generator.py

@@ -10,13 +10,21 @@ parser.add_argument('--dimension', default=5, type=int, help='Grid dimension')
 parser.add_argument('--height', type=float, help='Height of battery')
 parser.add_argument('--hole', default='AA', help='Hole diameter (mm or A, AA, AAA)')
 parser.add_argument('--kerf', default=.1, type=float, help='Kerf')
-parser.add_argument('--horizontal-finger', default=10.0, type=float, help='Width of horizontal fingers')
-parser.add_argument('--vertical-finger', default=5.0, type=float, help='Width of vertical fingers')
+parser.add_argument('--corner-length', default=4, help='Length of stretch corner in material thicknesses')
+parser.add_argument('--stretch', default=1.05, type=float, help='Reduction factor of stretch material')
+parser.add_argument('--horizontal-finger', default=5.0, type=float, help='Width of horizontal fingers')
+parser.add_argument('--vertical-finger', default=15.0, type=float, help='Width of vertical fingers')
 parser.add_argument('--padding', default=1.5, type=float, help='Padding around holes')
-parser.add_argument('--outside-padding', default=2, type=float, help='Extra padding between holes and wall')
+parser.add_argument('--outside-padding', default=4.0, type=float, help='Extra padding between holes and wall')
+parser.add_argument('--extra-height', default=2.0, type=float, help='Extra vertical space')
 parser.add_argument('--thickness', default=3.0, type=float, help='Thickness of material')
 parser.add_argument('--lid', default=0.2, type=float, help='How much extra play to give the lid')
-
+parser.add_argument('--tooth', default=0.8, type=float, help='How much to round the edges of the teeth')
+parser.add_argument('--flex-width', default=.5, type=float, help='Spacing (in material thickness) between flex lines')
+parser.add_argument('--flex-cut', default=5.0, type=float, help='Length (in material thickness) of flex cuts')
+parser.add_argument('--flex-gap', default=1.0, type=float, help='Gap (in material thickness) between flex cuts')
+parser.add_argument('--plug-play', default=0.8, type=float, help='How much smaller to make the plug than the hole')
+parser.add_argument('--verbose', action='store_true', help='Print computed parameter values')
 args = parser.parse_args()
 assert (args.dimension % 2) == 1
 
@@ -36,42 +44,93 @@ else:
     args.hole = float(args.hole)
     assert(args.height != None)
 
-args.kerf2         = args.kerf/2
-args.grid          = args.hole+args.padding
-args.radius        = args.hole/2
-args.interior_edge = args.grid*args.dimension*0.5+args.outside_padding
-args.exterior_edge = args.interior_edge+args.thickness
-args.interior_leg  = (args.interior_edge-args.horizontal_finger-args.kerf)/2
-args.n_hor_fingers = int(args.exterior_edge/args.horizontal_finger/2)
-args.exterior_leg  = (args.exterior_edge-(2*args.n_hor_fingers-1)*args.horizontal_finger+args.kerf)/2
-args.exterior_slot = (args.exterior_edge-args.horizontal_finger+args.kerf)/2
-args.n_ver_fingers = int(args.height/args.vertical_finger/2)
-args.vertical_finger = args.height/args.n_ver_fingers/2
-
-DIMX   = 2.9*args.grid*args.dimension
-DIMY   = 3.8*args.grid*args.dimension
+SUITABLE = False
+while not SUITABLE:
+    args.kerf2         = args.kerf/2
+    args.grid          = args.hole+args.padding
+    args.radius        = args.hole/2
+    args.corner        = args.corner_length*args.thickness
+    args.corner_s      = args.corner*args.stretch
+    args.corner_radius = 3*args.corner_s/math.pi
+    args.plug_radius   = args.corner_radius-args.thickness
+    args.corner_inset  = args.corner_s*math.sqrt(3)/math.pi
+    args.plug_inset    = args.plug_radius/math.sqrt(3)
+    args.interior_edge = args.grid*args.dimension*0.5+args.outside_padding
+    args.opening_edge  = args.interior_edge-args.thickness
+    args.plug_edge     = min(args.opening_edge, .5*math.sqrt(3)*args.interior_edge)-args.plug_play
+    args.disc_radius   = 0.45*(math.sqrt(3)-1)*args.plug_edge+args.plug_inset
+    args.exterior_edge = args.interior_edge+2.0*args.thickness
+    args.interior_leg  = (args.interior_edge-args.horizontal_finger-args.kerf)/2-args.corner_inset
+    finger_length      = args.interior_edge-2.0*args.corner_inset
+    args.n_hor_fingers = max(int(finger_length/args.horizontal_finger/2), 1)
+    args.exterior_leg  = (finger_length-(2*args.n_hor_fingers-1)*args.horizontal_finger+args.kerf)/2
+    args.wall_leg      = (args.interior_edge-args.corner-(2*args.n_hor_fingers-1)*args.horizontal_finger+args.kerf)/2
+    args.exterior_slot = (args.interior_edge-args.horizontal_finger+args.kerf)/2
+    args.n_ver_fingers = int((args.height+args.extra_height)/args.vertical_finger)
+    top_slot           = args.extra_height+args.thickness+0.45*args.height
+    args.slots         = [top_slot, top_slot+15.0]
+    if args.exterior_leg > 2:
+        SUITABLE=True
+    else:
+        args.outside_padding += .5
+        args.padding         += .2 # Try again with more padding
+
+if args.verbose:
+    print(args, file=sys.stderr)
+
+BOX    = 2.0*args.exterior_edge+5.0
+DIMX   = 3.0*BOX
+DIMY   = 2.0*BOX+args.height+args.extra_height+3.0*args.thickness+5.0
 PI3    = math.pi/3
 
+HOLES  = ''
+SHAPES = ''
+MARKS  = ''
+
 def draw_grid(cx, cy):
+    global HOLES
     for row in range(-int(args.dimension/2), int((args.dimension+1)/2)):
         cyr = cy+args.grid*row*math.sin(PI3)
         num_col = args.dimension-abs(row)
         cxr = cx-.5*args.grid*(num_col-1.0)
         for col in range(num_col):
-            print('<circle cx="%.2f" cy="%.2f" r="%.2f" stroke="black" fill="none"/>' % (cxr+col*args.grid, cyr, args.radius))
+            HOLES += '<circle cx="%.2f" cy="%.2f" r="%.2f"/>\n' % (cxr+col*args.grid, cyr, args.radius)
 
-def draw_plane(cx, cy, interior=False):
-    if interior:
+def draw_disc(cx, cy, layer):
+    global HOLES, SHAPES, MARKS
+    turtle       = svgturtle.SvgTurtle(cx, cy)
+    turtle.penup()
+    turtle.forward(args.disc_radius)
+    turtle.pendown()
+    turtle.left(90)
+    turtle.circle(args.disc_radius)
+    turtle.penup()
+    turtle.home()
+    if layer=='disc':
+        HOLES += '<path d="%s"/>\n' % turtle.to_s()
+    else:
+        MARKS += '<path d="%s"/>\n' % turtle.to_s()
+
+def draw_plane(cx, cy, layer):
+    global HOLES, SHAPES, MARKS
+    if layer=='interior':
         edge = args.interior_edge
+    elif layer=='opening':
+        edge = args.opening_edge
+    elif layer=='plug' or layer=='plug_mark':
+        edge = args.plug_edge
     else:
         edge = args.exterior_edge
     turtle       = svgturtle.SvgTurtle(cx, cy)
     turtle.penup()
+    if layer=='plug_mark':
+        turtle.right(30)
     turtle.forward(edge)
     turtle.right(120)
-    turtle.pendown()
-    if interior:
-        for side in range(6):
+    if layer=='interior':
+        turtle.forward(args.corner_inset)
+        turtle.pendown()
+        for side in range(5):
             turtle.forward(args.interior_leg)
             turtle.left(90)
             turtle.forward(args.thickness)
@@ -81,75 +140,197 @@ def draw_plane(cx, cy, interior=False):
             turtle.forward(args.thickness)
             turtle.left(90)
             turtle.forward(args.interior_leg)
+            turtle.circle(-args.corner_radius, 60)
+        turtle.forward(edge-2.0*args.corner_inset)
+        turtle.circle(-args.corner_radius, 60)
+    elif layer=='plug' or layer=='plug_mark':
+        turtle.pendown()
+        for side in range(3):
+            turtle.forward(0.5*edge)
+            turtle.right(90)
+            turtle.circle(0.5*edge, 120)
+            turtle.right(90)
+            turtle.forward(0.5*edge)
             turtle.right(60)
     else:
+        turtle.pendown()
         for side in range(6):
+            turtle.forward(edge)
+            turtle.right(60)
+    if layer=='plug':
+        HOLES += '<path d="%s"/>\n' % turtle.to_s()
+    elif layer=='plug_mark':
+        MARKS += '<path d="%s"/>\n' % turtle.to_s()
+    else:
+        SHAPES += '<path d="%s"/>\n' % turtle.to_s()
+    turtle.reset()
+    turtle.penup()
+    if layer=='bottom' or layer=='rim':
+        turtle.forward(args.interior_edge)
+        turtle.right(120)
+        turtle.forward(args.corner_inset)
+        for side in range(5):
             for finger in range(args.n_hor_fingers):
                 turtle.forward(args.exterior_leg if finger == 0 else args.horizontal_finger+args.kerf)
-                turtle.right(90)
-                turtle.forward(args.thickness)
+                turtle.pendown()
                 turtle.left(90)
+                turtle.forward(args.thickness)
+                turtle.right(90)
                 turtle.forward(args.horizontal_finger-args.kerf)
-                turtle.left(90)
+                turtle.right(90)
                 turtle.forward(args.thickness)
                 turtle.right(90)
+                turtle.forward(args.horizontal_finger-args.kerf)
+                turtle.penup()
+                turtle.right(180)
+                turtle.forward(args.horizontal_finger-args.kerf)
             turtle.forward(args.exterior_leg)
-            turtle.right(60)
-    print('<path d="%s" fill="none" stroke="black"/>' % turtle.to_s())
-
-def draw_side(x0, y0, h, slots):
-    turtle = svgturtle.SvgTurtle(x0, y0+args.thickness)
-    for finger in range(args.n_hor_fingers):
-        turtle.forward(args.exterior_leg-args.kerf if finger == 0 else args.horizontal_finger-args.kerf)
+            turtle.pendown()
+            turtle.left(90)
+            turtle.forward(args.thickness)
+            turtle.right(90)
+            turtle.circle(-args.corner_radius-args.thickness, 60)
+            turtle.right(90)
+            turtle.forward(args.thickness)
+            turtle.right(90)
+            turtle.circle(args.corner_radius, 60)
+            turtle.penup()
+            turtle.right(180)
+            turtle.circle(-args.corner_radius, 60)
+        turtle.forward(args.interior_edge-2*args.corner_inset)
+        turtle.pendown()
         turtle.left(90)
         turtle.forward(args.thickness)
         turtle.right(90)
-        turtle.forward(args.horizontal_finger+args.kerf)
+        turtle.circle(-args.corner_radius-args.thickness, 60)
         turtle.right(90)
         turtle.forward(args.thickness)
-        turtle.left(90)
-    turtle.forward(args.exterior_leg-args.kerf-args.thickness)
-    turtle.right(90)
-    for finger in range(args.n_ver_fingers):
-        turtle.forward(args.vertical_finger-(args.kerf/2 if finger==0 else args.kerf))
-        turtle.left(90)
-        turtle.forward(args.thickness)
         turtle.right(90)
-        turtle.forward(args.vertical_finger+args.kerf)
-        turtle.right(90)
-        if finger < args.n_ver_fingers-1:
-            turtle.forward(args.thickness)
+        turtle.circle(args.corner_radius, 60)
+        HOLES += '<path d="%s"/>\n' % turtle.to_s()
+
+def draw_flex(t, h):
+    global HOLES
+    turtle = svgturtle.SvgTurtle(t.x, t.y)
+    gap    = args.flex_gap*args.thickness
+    ncut   = max(int((h-gap) // (args.flex_cut*args.thickness)), 1)
+    cut    = ((h-gap) / ncut) - gap
+    dx     = args.flex_width*args.thickness
+    nlines = int(args.corner // dx)
+    x0     = .5*(args.corner - (nlines-1)*dx)
+
+    turtle.forward(x0)
+    for line in range(nlines):
+        turtle.pendown()
+        if (line % 2) == 0:
+            turtle.right(90)
+            turtle.forward(gap+cut)
+            for section in range(ncut-2):
+                turtle.penup()
+                turtle.forward(gap)
+                turtle.pendown()
+                turtle.forward(gap+2*cut)
+            turtle.penup()
+            turtle.forward(gap)
+            if (ncut % 2) == 0:
+                turtle.pendown()
+                turtle.forward(gap+cut)
+                turtle.penup()
             turtle.left(90)
-    turtle.forward(args.exterior_edge-args.thickness)
-    turtle.right(90)
-    for finger in range(args.n_ver_fingers):
-        turtle.forward(args.vertical_finger-(args.kerf/2 if finger==0 else args.kerf))
+        else:
+            turtle.left(90)
+            if (ncut % 2) == 1:
+                turtle.forward(gap+cut)
+            for section in range(ncut-1-(ncut % 2)):
+                turtle.penup()
+                turtle.forward(gap)
+                turtle.pendown()
+                turtle.forward(gap+2*cut)
+            turtle.penup()
+            turtle.forward(gap)
+            turtle.right(90)
+        turtle.forward(dx)
+    HOLES += '<path d="%s"/>\n' % turtle.to_s()
+
+def draw_case_h(turtle, h, top):
+    turtle.forward(0.5*args.interior_edge-0.5*args.corner)
+    for side in range(6):
         turtle.left(90)
         turtle.forward(args.thickness)
         turtle.right(90)
-        turtle.forward(args.vertical_finger+args.kerf)
+        if top:
+            draw_flex(turtle, h+2*args.thickness)
+        turtle.forward(args.corner)
         turtle.right(90)
-        if finger < args.n_ver_fingers-1:
+        turtle.forward(args.thickness)
+        turtle.left(90)
+        if side == 5:
+            break
+        turtle.forward(args.wall_leg-0.5*args.kerf)
+        for finger in range(args.n_hor_fingers):
+            if finger > 0:
+                turtle.forward(args.horizontal_finger-args.kerf)
+            turtle.left(90)
+            turtle.forward(args.thickness)
+            turtle.right(90)
+            turtle.forward(args.horizontal_finger+args.kerf)
+            turtle.right(90)
             turtle.forward(args.thickness)
             turtle.left(90)
-    print('<path d="%s" fill="none" stroke="black"/>' % turtle.to_s())
+        turtle.forward(args.wall_leg-0.5*args.kerf)
+    turtle.forward(0.5*args.interior_edge-0.5*args.corner)
+
+def draw_case_v(turtle, h):
+    ey = turtle.y+h
+    leg = (h-(args.n_ver_fingers-0.66)*args.vertical_finger)/2.0
+    slope = args.vertical_finger/math.sqrt(18)
+    turtle.forward(leg)
+    for finger in range(args.n_ver_fingers):
+        ty = ey if finger==args.n_ver_fingers-1 else turtle.y+args.vertical_finger
+        turtle.circle(args.tooth, 135)
+        turtle.forward(slope)
+        turtle.circle(-args.tooth, 135)
+        turtle.forward(0.66*args.vertical_finger)
+        turtle.circle(-args.tooth, 135)
+        turtle.forward(slope)
+        turtle.circle(args.tooth, 135)
+        turtle.forward(ty-turtle.y)
+
+def draw_case(x0, y0, h, slots):
+    global HOLES, SHAPES
+    turtle = svgturtle.SvgTurtle(x0, y0+args.thickness)
+    draw_case_h(turtle, h, True)
+    turtle.right(90)
+    draw_case_v(turtle, h)
+    turtle.right(90)
+    draw_case_h(turtle, h, False)
+    turtle.penup()
+    turtle.left(90)
+    turtle.back(h)
+    turtle.pendown()
+    draw_case_v(turtle, h)
+    SHAPES += '<path d="%s"/>\n' % turtle.to_s()
     for slot in slots:
-        x = x0+args.exterior_slot
-        y = y0+slot
-        w = args.horizontal_finger-args.kerf
-        h = args.thickness-args.kerf
-        print('<rect x="%.2f" y="%.2f" width="%.2f" height="%.2f" fill="none" stroke="black"/>' % (x, y, w, h))
+        for side in range(5):
+            x = x0+(side+.5)*args.interior_edge+args.exterior_slot
+            y = y0+slot
+            w = args.horizontal_finger-args.kerf
+            h = args.thickness-args.kerf
+            HOLES += '<rect x="%.2f" y="%.2f" width="%.2f" height="%.2f"/>\n' % (x, y, w, h)
 
 print('<svg viewBox="0 0 %.2f %.2f" width="%.2fmm" height="%.2fmm" stroke-width="0.1" xmlns="http://www.w3.org/2000/svg">' % (DIMX, DIMY, DIMX, DIMY))
-draw_grid(0.65*args.grid*args.dimension, 0.60*args.grid*args.dimension)
-draw_plane(0.65*args.grid*args.dimension, 0.60*args.grid*args.dimension, True)
-draw_grid(1.90*args.grid*args.dimension, 0.60*args.grid*args.dimension)
-draw_plane(1.90*args.grid*args.dimension, 0.60*args.grid*args.dimension, True)
-draw_plane(0.65*args.grid*args.dimension, 1.90*args.grid*args.dimension)
-draw_side(0.05*args.grid*args.dimension, 2.50*args.grid*args.dimension, args.height, [args.height*.3, args.height*.7])
-draw_side(0.75*args.grid*args.dimension, 2.50*args.grid*args.dimension, args.height, [args.height*.3, args.height*.7])
-draw_side(1.45*args.grid*args.dimension, 2.50*args.grid*args.dimension, args.height, [args.height*.3, args.height*.7])
-draw_side(2.15*args.grid*args.dimension, 2.50*args.grid*args.dimension, args.height, [args.height*.3, args.height*.7])
-draw_side(1.35*args.grid*args.dimension, 1.25*args.grid*args.dimension, args.height, [args.height*.3, args.height*.7])
-draw_side(2.05*args.grid*args.dimension, 1.25*args.grid*args.dimension, args.height, [args.height*.3, args.height*.7])
+draw_grid(0.5*BOX, 0.5*BOX)
+draw_plane(0.5*BOX, 0.5*BOX, 'interior')
+draw_grid(1.5*BOX, 0.5*BOX)
+draw_plane(1.5*BOX, 0.5*BOX, 'interior')
+draw_plane(0.5*BOX, 1.5*BOX, 'bottom')
+draw_plane(1.5*BOX, 1.5*BOX, 'rim')
+draw_plane(1.5*BOX, 1.5*BOX, 'opening')
+draw_disc(1.5*BOX, 1.5*BOX, 'disc')
+draw_plane(2.5*BOX, 0.5*BOX, 'plug')
+draw_plane(2.5*BOX, 1.5*BOX, 'lid')
+draw_plane(2.5*BOX, 1.5*BOX, 'plug_mark')
+draw_disc(2.5*BOX, 1.5*BOX, 'disc_mark')
+draw_case(0.05*args.grid*args.dimension, 2.0*BOX, args.height+args.extra_height+args.thickness, args.slots)
+print('<g fill="none" stroke="black">', SHAPES, '</g>', '<g fill="none" stroke="red">', HOLES, '</g>', '<g fill="none" stroke="blue">', MARKS, '</g>', sep='\n')
 print('</svg>')

svgturtle.py

@@ -40,6 +40,41 @@ class SvgTurtle():
     def right(self, angle):
         self.heading = (self.heading + angle*self.cvtangle) % math.tau
 
+    def circle(self, radius, extent=360, steps=None):
+        if steps:
+            w  = 1.0*extent/steps
+            w2 = 0.5*w
+            l  = 2.0*radius*math.sin(w2*math.pi/180.0)
+            if radius < 0:
+                l, w, w2 = -l, -w, -w2
+            self.left(w2)
+            for i in range(steps):
+                self.forward(l)
+                self.left(w)
+            self.right(w2)
+        else:
+            if extent>355:
+                self.circle(radius, 355)
+                extent -= 355
+            ra  = self.cvtangle*(extent if radius < 0 else -extent)
+            cx  = self.x+radius*math.cos(self.heading-.5*math.pi)
+            cy  = self.y+radius*math.sin(self.heading-.5*math.pi)
+            th  = self.heading+.5*math.pi+ra
+            dx  = cx+radius*math.cos(th)-self.x
+            dy  = cy+radius*math.sin(th)-self.y
+            lg  = 1 if extent >= 180 else 0
+            sw  = 0 if radius > 0 else 1
+            if self.pen:
+                if self.path == '':
+                    self.path = "M %.2f,%.2f" % (self.x,self.y)
+                self.path += " a %.2f %.2f %.2f %d %d %.2f %.2f" % (radius, radius, extent, lg, sw, dx, dy)
+            elif self.path != '':
+                self.path += " m %.2f, %.2f" % (dx, dy)
+            self.x += dx
+            self.y += dy
+            self.heading = (self.heading + ra) % math.tau
+
+
     def to_s(self):
         return self.path
 
@@ -47,6 +82,8 @@ class SvgTurtle():
         self.x        = self.homex
         self.y        = self.homey
         self.heading  = 0
+        if self.path != '':
+            self.path += " M %.2f, %.2f" % (self.x, self.y)
 
     def reset(self):
         self.path = ''

svgturtletest.py

@@ -0,0 +1,43 @@
+#!/usr/bin/env python3
+
+import svgturtle
+
+print('<svg viewBox="0 0 2000 2000" xmlns="http://www.w3.org/2000/svg">')
+turtle_tl = svgturtle.SvgTurtle(500, 750)
+turtle_tr = svgturtle.SvgTurtle(1500, 750)
+turtle_bl = svgturtle.SvgTurtle(500, 1000)
+turtle_br = svgturtle.SvgTurtle(1500, 1000)
+ANGLE=0
+for i in range(7):
+    turtle_tl.home()
+    turtle_tl.left(ANGLE)
+    turtle_tl.circle(110+i*50, (i+1)*45, 50)
+    turtle_bl.home()
+    turtle_bl.right(ANGLE)
+    turtle_bl.circle(-(110+i*50), (i+1)*45, 50)
+    turtle_tr.home()
+    turtle_tr.right(ANGLE)
+    turtle_tr.circle(140+i*50, (i+1)*45, 50)
+    turtle_br.home()
+    turtle_br.left(ANGLE)
+    turtle_br.circle(-(140+i*50), (i+1)*45, 50)
+print('<path fill="none" stroke="black" d="%s %s %s %s"/>' % (turtle_tl.to_s(), turtle_tr.to_s(), turtle_bl.to_s(), turtle_br.to_s()))
+turtle_tl.reset()
+turtle_tr.reset()
+turtle_bl.reset()
+turtle_br.reset()
+for i in range(8):
+    turtle_tl.home()
+    turtle_tl.left(ANGLE)
+    turtle_tl.circle(100+i*50, (i+1)*45)
+    turtle_bl.home()
+    turtle_bl.right(ANGLE)
+    turtle_bl.circle(-(100+i*50), (i+1)*45)
+    turtle_tr.home()
+    turtle_tr.right(ANGLE)
+    turtle_tr.circle(130+i*50, (i+1)*45)
+    turtle_br.home()
+    turtle_br.left(ANGLE)
+    turtle_br.circle(-(130+i*50), (i+1)*45)
+print('<path fill="none" stroke="blue" d="%s %s %s %s"/>' % (turtle_tl.to_s(), turtle_tr.to_s(), turtle_bl.to_s(), turtle_br.to_s()))
+print('</svg>')