lipo-flat-mount.scad

   1 // -*- C -*-
   2
   3 include <nutbox.scad>
   4 include <utils.scad>
   5
   6 // pimoroni 3000mAh
   7 battery = [ 51.5,
   8             81.3,
   9             8.0 ];
  10
  11 battery_wall = 2.0;
  12 battery_wall_unsupp = 4.0;
  13 battery_wall_top_gap = 0.75;
  14
  15 battery_keeper_m_th = 4;
  16 battery_keeper_m_w = 4;
  17 battery_keeper_x_gap = 0.75; // each side
  18 battery_keeper_y_gap_overhang = 0.75;
  19 battery_keeper_y_gap_nutbox = 1.0;
  20 battery_keeper_z_gap_nutbox = 0.50;
  21 battery_keeper_z_gap_overhang = 0.75;
  22
  23 battery_keeper_x_th_min = 1.5 * 1.5;
  24 battery_keeper_x_th_max = 2.5 * 1.5;
  25 battery_keeper_x_w  = 5;
  26 battery_keeper_x_n  = 5;
  27
  28 battery_keeper_screw_x_off = -2.5;
  29
  30 battery_wire_y = 4;
  31
  32 battery_nutbox = nutbox_data_M3;
  33
  34 // calculated
  35
  36 battery_fix_sz = NutBox_outer_size(battery_nutbox);
  37
  38 battery_nutbox_z = max( battery[2] + battery_wall_top_gap,
  39                         NutBox_h_base(battery_nutbox) );
  40 battery_keeper_overhang_z = battery[2] + battery_keeper_m_th
  41   + battery_keeper_z_gap_overhang;
  42 battery_keeper_overhang_wall = battery_keeper_m_w;
  43 battery_keeper_overhang_th = battery_keeper_m_th;
  44
  45 // calculated outputs
  46
  47 battery_keeper_tab_top_z = battery_nutbox_z
  48      + battery_keeper_z_gap_nutbox + battery_keeper_m_th;
  49
  50 battery_keeper_legs_top_z = battery_keeper_overhang_z
  51                             + battery_keeper_overhang_th;
  52
  53 battery_keeper_frame_top_z = battery[2] + battery_keeper_m_th;
  54
  55 module BatteryPlan(){
  56   rectfromto([ -battery[0]/2, 0          ],
  57              [ +battery[0]/2, battery[1] ]);
  58 }
  59
  60 module BatteryBase(){ ////toplevel
  61   // wall
  62   linextr(-0.1, battery[2] - battery_wall_top_gap, convexity=7) {
  63     difference(){
  64       union(){
  65         offset(r=battery_wall) BatteryPlan();
  66         rectfromto([ 0,0 ],
  67                    [ -(battery[0]/2 + battery_wall_unsupp), battery[1]/3 ]);
  68       }
  69       BatteryPlan();
  70       rectfromto([ battery_fix_sz/2 - 0.5
  71                    + battery_keeper_screw_x_off, -30 ],
  72                  [ -battery[0], battery_wire_y ]);
  73     }
  74   }
  75
  76   // nutbox
  77   translate([battery_keeper_screw_x_off, -battery_fix_sz/2, battery_nutbox_z])
  78     NutBox(battery_nutbox, battery_nutbox_z + 0.1);
  79
  80   // overhang for legs at rear
  81   for (m=[0,1]) {
  82     mirror([m,0,0]) {
  83       translate([ battery[0]/2, battery[1], 0]) {
  84         difference(){
  85           linextr(-0.1,
  86                   battery_keeper_overhang_z
  87                   + battery_keeper_overhang_th,
  88                   convexity=1)
  89             rectfromto([ -battery_keeper_m_w*2, -battery_keeper_m_w ],
  90                        [ battery_keeper_overhang_wall, battery_wall ]);
  91           linextr(-1, battery_keeper_overhang_z,
  92                   convexity=1)
  93             rectfromto([-20, -20], [0,0]);
  94         }
  95       }
  96     }
  97   }
  98 }
  99
 100 module BatteryKeeper(){ ////toplevel
 101   // A-frame
 102   translate([0,0, battery[2]]) {
 103     linextr(0, battery_keeper_m_th) {
 104       intersection(){
 105         // main legs
 106         translate([0,  +battery[1], 0])
 107           multmatrix([[ 1, -battery_keeper_screw_x_off/battery[1], 0, 0, ],
 108                       [ 0,1,0, 0, ],
 109                       [ 0,0,1, 0, ]])
 110           translate([0, -battery[1], 0])
 111         for (sx=[-1,+1]) {
 112           multmatrix([[ 1,0,0, 0, ],
 113                       [ 0,1,0, 0, ],
 114                       [ 0,0,1, 0, ]] +
 115                      sx *
 116                      ( battery[0]/2 - 0.5 * battery_keeper_m_w
 117                        - battery_keeper_x_gap ) /
 118                      ( battery[1] - 0.5 * battery_keeper_m_w )
 119                      *
 120                      [[ 0,1,0, 0, ],
 121                       [ 0,0,0, 0, ],
 122                       [ 0,0,0, 0, ]])
 123             rectfromto([ -battery_keeper_m_w/2,
 124                          battery_keeper_y_gap_nutbox ],
 125                        [ +battery_keeper_m_w/2,
 126                          battery[1] - battery_keeper_y_gap_overhang ]);
 127         }
 128
 129         // shape to round off the leg end corners
 130         hull(){
 131           for (sx=[-1,+1]) {
 132             translate([ sx * ( battery[0]/2 - battery_keeper_m_w/2
 133                                -battery_keeper_x_gap) ,
 134                         battery[1] - battery_keeper_m_w/2
 135                         -battery_keeper_y_gap_overhang ])
 136               circle(r = battery_keeper_m_w/2);
 137           }
 138           square(center=true, [ battery[0], 1 ]);
 139         }
 140       }
 141     }
 142
 143     // x struts
 144     for (i=[0 : battery_keeper_x_n-1]) {
 145       linextr(0,
 146               battery_keeper_x_th_min +
 147               (battery_keeper_x_th_max - battery_keeper_x_th_min)
 148               * pow( i/(battery_keeper_x_n-1)*2 - 1 , 2)
 149               ) {
 150         difference(){
 151           translate([0, battery[1] * ((i + 0.5) / battery_keeper_x_n)])
 152             square(center=true, [ battery[0], battery_keeper_x_w ]);
 153           children(0);
 154         }
 155       }
 156     }
 157   }
 158
 159   // tab for screw and nutbox
 160   translate([battery_keeper_screw_x_off,
 161              0,
 162              battery_nutbox_z + battery_keeper_z_gap_nutbox])
 163     linextr(0, battery_keeper_m_th, convexity=4) {
 164     difference(){
 165       rectfromto([ -battery_fix_sz/2, -battery_fix_sz ],
 166                  [ +battery_fix_sz/2,
 167                    0.5 * battery[1] / battery_keeper_x_n +
 168                    0.5 * battery_keeper_m_w ]);
 169       translate([ 0, -battery_fix_sz/2 ])
 170         circle(r = battery_nutbox[0]/2);
 171     }
 172   }
 173 }
 174
 175 module BatteryDemo(){ ////toplevel
 176   color("grey") BatteryBase();
 177   BatteryKeeper() { union(){ } }
 178 }
 179