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 module BatteryPlan(){
  46   rectfromto([ -battery[0]/2, 0          ],
  47              [ +battery[0]/2, battery[1] ]);
  48 }
  49
  50 module BatteryBase(){ ////toplevel
  51   // wall
  52   linextr(-0.1, battery[2] - battery_wall_top_gap, convexity=7) {
  53     difference(){
  54       union(){
  55         offset(r=battery_wall) BatteryPlan();
  56         rectfromto([ 0,0 ],
  57                    [ -(battery[0]/2 + battery_wall_unsupp), battery[1]/3 ]);
  58       }
  59       BatteryPlan();
  60       rectfromto([ battery_fix_sz/2 - 0.5
  61                    + battery_keeper_screw_x_off, -30 ],
  62                  [ -battery[0], battery_wire_y ]);
  63     }
  64   }
  65
  66   // nutbox
  67   translate([battery_keeper_screw_x_off, -battery_fix_sz/2, battery_nutbox_z])
  68     NutBox(battery_nutbox, battery_nutbox_z + 0.1);
  69
  70   // overhang for legs at rear
  71   for (m=[0,1]) {
  72     mirror([m,0,0]) {
  73       translate([ battery[0]/2, battery[1], 0]) {
  74         difference(){
  75           linextr(-0.1,
  76                   battery_keeper_overhang_z
  77                   + battery_keeper_overhang_th,
  78                   convexity=1)
  79             rectfromto([ -battery_keeper_m_w*2, -battery_keeper_m_w ],
  80                        [ battery_keeper_overhang_wall, battery_wall ]);
  81           linextr(-1, battery_keeper_overhang_z,
  82                   convexity=1)
  83             rectfromto([-20, -20], [0,0]);
  84         }
  85       }
  86     }
  87   }
  88 }
  89
  90 module BatteryKeeper(){ ////toplevel
  91   // A-frame
  92   translate([0,0, battery[2]]) {
  93     linextr(0, battery_keeper_m_th) {
  94       intersection(){
  95         // main legs
  96         translate([0,  +battery[1], 0])
  97           multmatrix([[ 1, -battery_keeper_screw_x_off/battery[1], 0, 0, ],
  98                       [ 0,1,0, 0, ],
  99                       [ 0,0,1, 0, ]])
 100           translate([0, -battery[1], 0])
 101         for (sx=[-1,+1]) {
 102           multmatrix([[ 1,0,0, 0, ],
 103                       [ 0,1,0, 0, ],
 104                       [ 0,0,1, 0, ]] +
 105                      sx *
 106                      ( battery[0]/2 - 0.5 * battery_keeper_m_w
 107                        - battery_keeper_x_gap ) /
 108                      ( battery[1] - 0.5 * battery_keeper_m_w )
 109                      *
 110                      [[ 0,1,0, 0, ],
 111                       [ 0,0,0, 0, ],
 112                       [ 0,0,0, 0, ]])
 113             rectfromto([ -battery_keeper_m_w/2,
 114                          battery_keeper_y_gap_nutbox ],
 115                        [ +battery_keeper_m_w/2,
 116                          battery[1] - battery_keeper_y_gap_overhang ]);
 117         }
 118
 119         // shape to round off the leg end corners
 120         hull(){
 121           for (sx=[-1,+1]) {
 122             translate([ sx * ( battery[0]/2 - battery_keeper_m_w/2
 123                                -battery_keeper_x_gap) ,
 124                         battery[1] - battery_keeper_m_w/2
 125                         -battery_keeper_y_gap_overhang ])
 126               circle(r = battery_keeper_m_w/2);
 127           }
 128           square(center=true, [ battery[0], 1 ]);
 129         }
 130       }
 131     }
 132
 133     // x struts
 134     for (i=[0 : battery_keeper_x_n-1]) {
 135       linextr(0,
 136               battery_keeper_x_th_min +
 137               (battery_keeper_x_th_max - battery_keeper_x_th_min)
 138               * pow( i/(battery_keeper_x_n-1)*2 - 1 , 2)
 139               ) {
 140         difference(){
 141           translate([0, battery[1] * ((i + 0.5) / battery_keeper_x_n)])
 142             square(center=true, [ battery[0], battery_keeper_x_w ]);
 143           children(0);
 144         }
 145       }
 146     }
 147   }
 148
 149   // tab for screw and nutbox
 150   translate([battery_keeper_screw_x_off,
 151              0,
 152              battery_nutbox_z + battery_keeper_z_gap_nutbox])
 153     linextr(0, battery_keeper_m_th, convexity=4) {
 154     difference(){
 155       rectfromto([ -battery_fix_sz/2, -battery_fix_sz ],
 156                  [ +battery_fix_sz/2,
 157                    0.5 * battery[1] / battery_keeper_x_n +
 158                    0.5 * battery_keeper_m_w ]);
 159       translate([ 0, -battery_fix_sz/2 ])
 160         circle(r = battery_nutbox[0]/2);
 161     }
 162   }
 163 }
 164
 165 module BatteryDemo(){ ////toplevel
 166   color("grey") BatteryBase();
 167   BatteryKeeper() { union(){ } }
 168 }
 169