lipo-flat-mount.scad

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