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      // NB does not include screw head
  50
  51 battery_keeper_legs_top_z = battery_keeper_overhang_z
  52                             + battery_keeper_overhang_th;
  53
  54 battery_keeper_frame_top_z = battery[2] + battery_keeper_m_th;
  55
  56 battery_mount_y_min = -battery_fix_sz;
  57 battery_mount_y_max = battery[1] + battery_wall;
  58 battery_mount_x_sz  = battery[0] + battery_wall_unsupp*2;
  59
  60 module BatteryPlan(){
  61   rectfromto([ -battery[0]/2, 0          ],
  62              [ +battery[0]/2, battery[1] ]);
  63 }
  64
  65 module BatteryBase(){ ////toplevel
  66   // wall
  67   linextr(-0.1, battery[2] - battery_wall_top_gap, convexity=7) {
  68     difference(){
  69       union(){
  70         offset(r=battery_wall) BatteryPlan();
  71         rectfromto([ 0,0 ],
  72                    [ -(battery[0]/2 + battery_wall_unsupp), battery[1]/3 ]);
  73       }
  74       BatteryPlan();
  75       rectfromto([ battery_fix_sz/2 - 0.5
  76                    + battery_keeper_screw_x_off, -30 ],
  77                  [ -battery[0], battery_wire_y ]);
  78     }
  79   }
  80
  81   // nutbox
  82   translate([battery_keeper_screw_x_off, -battery_fix_sz/2, battery_nutbox_z])
  83     NutBox(battery_nutbox, battery_nutbox_z + 0.1);
  84
  85   // overhang for legs at rear
  86   for (m=[0,1]) {
  87     mirror([m,0,0]) {
  88       translate([ battery[0]/2, battery[1], 0]) {
  89         difference(){
  90           linextr(-0.1,
  91                   battery_keeper_overhang_z
  92                   + battery_keeper_overhang_th,
  93                   convexity=1)
  94             rectfromto([ -battery_keeper_m_w*2, -battery_keeper_m_w ],
  95                        [ battery_keeper_overhang_wall, battery_wall ]);
  96           linextr(-1, battery_keeper_overhang_z,
  97                   convexity=1)
  98             rectfromto([-20, -20], [0,0]);
  99         }
 100       }
 101     }
 102   }
 103 }
 104
 105 module BatteryKeeper(){ ////toplevel
 106   // A-frame
 107   translate([0,0, battery[2]]) {
 108     linextr(0, battery_keeper_m_th) {
 109       intersection(){
 110         // main legs
 111         translate([0,  +battery[1], 0])
 112           multmatrix([[ 1, -battery_keeper_screw_x_off/battery[1], 0, 0, ],
 113                       [ 0,1,0, 0, ],
 114                       [ 0,0,1, 0, ]])
 115           translate([0, -battery[1], 0])
 116         for (sx=[-1,+1]) {
 117           multmatrix([[ 1,0,0, 0, ],
 118                       [ 0,1,0, 0, ],
 119                       [ 0,0,1, 0, ]] +
 120                      sx *
 121                      ( battery[0]/2 - 0.5 * battery_keeper_m_w
 122                        - battery_keeper_x_gap ) /
 123                      ( battery[1] - 0.5 * battery_keeper_m_w )
 124                      *
 125                      [[ 0,1,0, 0, ],
 126                       [ 0,0,0, 0, ],
 127                       [ 0,0,0, 0, ]])
 128             rectfromto([ -battery_keeper_m_w/2,
 129                          battery_keeper_y_gap_nutbox ],
 130                        [ +battery_keeper_m_w/2,
 131                          battery[1] - battery_keeper_y_gap_overhang ]);
 132         }
 133
 134         // shape to round off the leg end corners
 135         hull(){
 136           for (sx=[-1,+1]) {
 137             translate([ sx * ( battery[0]/2 - battery_keeper_m_w/2
 138                                -battery_keeper_x_gap) ,
 139                         battery[1] - battery_keeper_m_w/2
 140                         -battery_keeper_y_gap_overhang ])
 141               circle(r = battery_keeper_m_w/2);
 142           }
 143           square(center=true, [ battery[0], 1 ]);
 144         }
 145       }
 146     }
 147
 148     // x struts
 149     for (i=[0 : battery_keeper_x_n-1]) {
 150       linextr(0,
 151               battery_keeper_x_th_min +
 152               (battery_keeper_x_th_max - battery_keeper_x_th_min)
 153               * pow( i/(battery_keeper_x_n-1)*2 - 1 , 2)
 154               ) {
 155         difference(){
 156           translate([0, battery[1] * ((i + 0.5) / battery_keeper_x_n)])
 157             square(center=true, [ battery[0], battery_keeper_x_w ]);
 158           children(0);
 159         }
 160       }
 161     }
 162   }
 163
 164   // tab for screw and nutbox
 165   translate([battery_keeper_screw_x_off,
 166              0,
 167              battery_nutbox_z + battery_keeper_z_gap_nutbox])
 168     linextr(0, battery_keeper_m_th, convexity=4) {
 169     difference(){
 170       rectfromto([ -battery_fix_sz/2, -battery_fix_sz ],
 171                  [ +battery_fix_sz/2,
 172                    0.5 * battery[1] / battery_keeper_x_n +
 173                    0.5 * battery_keeper_m_w ]);
 174       translate([ 0, -battery_fix_sz/2 ])
 175         circle(r = battery_nutbox[0]/2);
 176     }
 177   }
 178 }
 179
 180 module BatteryDemo(){ ////toplevel
 181   color("grey") BatteryBase();
 182   BatteryKeeper() { union(){ } }
 183 }
 184