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 battery_keeper_frame_top_z = battery[2] + battery_keeper_m_th;
  50
  51 module BatteryPlan(){
  52   rectfromto([ -battery[0]/2, 0          ],
  53              [ +battery[0]/2, battery[1] ]);
  54 }
  55
  56 module BatteryBase(){ ////toplevel
  57   // wall
  58   linextr(-0.1, battery[2] - battery_wall_top_gap, convexity=7) {
  59     difference(){
  60       union(){
  61         offset(r=battery_wall) BatteryPlan();
  62         rectfromto([ 0,0 ],
  63                    [ -(battery[0]/2 + battery_wall_unsupp), battery[1]/3 ]);
  64       }
  65       BatteryPlan();
  66       rectfromto([ battery_fix_sz/2 - 0.5
  67                    + battery_keeper_screw_x_off, -30 ],
  68                  [ -battery[0], battery_wire_y ]);
  69     }
  70   }
  71
  72   // nutbox
  73   translate([battery_keeper_screw_x_off, -battery_fix_sz/2, battery_nutbox_z])
  74     NutBox(battery_nutbox, battery_nutbox_z + 0.1);
  75
  76   // overhang for legs at rear
  77   for (m=[0,1]) {
  78     mirror([m,0,0]) {
  79       translate([ battery[0]/2, battery[1], 0]) {
  80         difference(){
  81           linextr(-0.1,
  82                   battery_keeper_overhang_z
  83                   + battery_keeper_overhang_th,
  84                   convexity=1)
  85             rectfromto([ -battery_keeper_m_w*2, -battery_keeper_m_w ],
  86                        [ battery_keeper_overhang_wall, battery_wall ]);
  87           linextr(-1, battery_keeper_overhang_z,
  88                   convexity=1)
  89             rectfromto([-20, -20], [0,0]);
  90         }
  91       }
  92     }
  93   }
  94 }
  95
  96 module BatteryKeeper(){ ////toplevel
  97   // A-frame
  98   translate([0,0, battery[2]]) {
  99     linextr(0, battery_keeper_m_th) {
 100       intersection(){
 101         // main legs
 102         translate([0,  +battery[1], 0])
 103           multmatrix([[ 1, -battery_keeper_screw_x_off/battery[1], 0, 0, ],
 104                       [ 0,1,0, 0, ],
 105                       [ 0,0,1, 0, ]])
 106           translate([0, -battery[1], 0])
 107         for (sx=[-1,+1]) {
 108           multmatrix([[ 1,0,0, 0, ],
 109                       [ 0,1,0, 0, ],
 110                       [ 0,0,1, 0, ]] +
 111                      sx *
 112                      ( battery[0]/2 - 0.5 * battery_keeper_m_w
 113                        - battery_keeper_x_gap ) /
 114                      ( battery[1] - 0.5 * battery_keeper_m_w )
 115                      *
 116                      [[ 0,1,0, 0, ],
 117                       [ 0,0,0, 0, ],
 118                       [ 0,0,0, 0, ]])
 119             rectfromto([ -battery_keeper_m_w/2,
 120                          battery_keeper_y_gap_nutbox ],
 121                        [ +battery_keeper_m_w/2,
 122                          battery[1] - battery_keeper_y_gap_overhang ]);
 123         }
 124
 125         // shape to round off the leg end corners
 126         hull(){
 127           for (sx=[-1,+1]) {
 128             translate([ sx * ( battery[0]/2 - battery_keeper_m_w/2
 129                                -battery_keeper_x_gap) ,
 130                         battery[1] - battery_keeper_m_w/2
 131                         -battery_keeper_y_gap_overhang ])
 132               circle(r = battery_keeper_m_w/2);
 133           }
 134           square(center=true, [ battery[0], 1 ]);
 135         }
 136       }
 137     }
 138
 139     // x struts
 140     for (i=[0 : battery_keeper_x_n-1]) {
 141       linextr(0,
 142               battery_keeper_x_th_min +
 143               (battery_keeper_x_th_max - battery_keeper_x_th_min)
 144               * pow( i/(battery_keeper_x_n-1)*2 - 1 , 2)
 145               ) {
 146         difference(){
 147           translate([0, battery[1] * ((i + 0.5) / battery_keeper_x_n)])
 148             square(center=true, [ battery[0], battery_keeper_x_w ]);
 149           children(0);
 150         }
 151       }
 152     }
 153   }
 154
 155   // tab for screw and nutbox
 156   translate([battery_keeper_screw_x_off,
 157              0,
 158              battery_nutbox_z + battery_keeper_z_gap_nutbox])
 159     linextr(0, battery_keeper_m_th, convexity=4) {
 160     difference(){
 161       rectfromto([ -battery_fix_sz/2, -battery_fix_sz ],
 162                  [ +battery_fix_sz/2,
 163                    0.5 * battery[1] / battery_keeper_x_n +
 164                    0.5 * battery_keeper_m_w ]);
 165       translate([ 0, -battery_fix_sz/2 ])
 166         circle(r = battery_nutbox[0]/2);
 167     }
 168   }
 169 }
 170
 171 module BatteryDemo(){ ////toplevel
 172   color("grey") BatteryBase();
 173   BatteryKeeper() { union(){ } }
 174 }
 175