epaper_door_case/fpc_adapter.scad

// Waveshare e-Paper FPC Adapter — parametric mockup
//
// Coordinate system:
//   Origin at PCB Z- face, lower-left corner (X=0, Y=0, Z=0).
//   X: board long axis (width)
//   Y: board short axis (height)
//   Z: 0 = bottom face (Z-); PCB_T = top face (Z+, component side)
//
// Two FPC connectors sit on the Z+ face:
//   Connector A (Y+): FPC exits in +Y direction
//   Connector B (Y-): FPC exits in -Y direction
//
// Mounting bosses hang from the Z- face (z=0, downward in -Z).
// Stud pins extend upward from z=0 through the PCB locating holes.
// When the board is flipped for ceiling-mount (rotate([0,180,0])):
//   bosses point toward the ceiling, stud tips snap down through the PCB.
//
// fpc_adapter() always produces boss geometry.
// PCB / connector / FPC visuals are shown only in $preview.

// ── PCB ────────────────────────────────────────────────────────────────
PCB_W  = 32.0;
PCB_H  = 18.0;
PCB_T  = 1.6;    // standard; measured ~1.72
PCB_R  = 3.0;    // corner radius

// ── Mounting holes ─────────────────────────────────────────────────────
HOLE_D   = 3.0;
HOLE_MX  = 3.75;  // hole center from nearest X edge (2.25 clearance + 1.5 radius)
HOLE_MY  = 3.75;  // hole center from nearest Y edge

// ── FPC connectors (simple box approximation) ──────────────────────────
CON_W    = 15.5;  // connector width along X
CON_D    = 5.85;  // connector depth along Y
CON_H    = 2.05;  // connector height above Z+ face (total stack 3.65 − PCB_T)
CON_CX   = PCB_W / 2;
CON_A_Y1 = PCB_H - CON_D;  // Connector A inner face (Y+ side)
CON_B_Y0 = 0;               // Connector B outer face (Y- side)

// ── FPC cable (simple flat box) ────────────────────────────────────────
FPC_W  = 12.5;
FPC_T  = 0.3;

// Default stub lengths. 0 = no cable; >0 = stub that many mm.
FPC_YP = 20;
FPC_YN = 0;

// ── Mounting bosses ────────────────────────────────────────────────────
BOSS_D  = 6.0;           // boss outer diameter
BOSS_H  = 2.0;           // boss standoff height (extends below Z- face)
SCREW_D = 3.2;           // screw diameter; hole drilled at 0.7× for self-tap
STUD_R  = 1.5;           // locating stud radius
STUD_H  = PCB_T + 1.0;  // stud height: pierces PCB with 1 mm snap-through

// ═══════════════════════════════════════════════════════════════════════
// Private helpers
// ═══════════════════════════════════════════════════════════════════════

module _pcb_shape(h) {
  r = PCB_R;
  linear_extrude(h)
    offset(r=r)
      translate([r, r])
        square([PCB_W - 2*r, PCB_H - 2*r]);
}

// Boss hangs from Z- face (z=0) downward; stud pin rises through PCB hole.
// Stud diagonal: (X1,Y1)+(X2,Y2); screw diagonal: (X1,Y2)+(X2,Y1).
module _adapt_boss(px, py, stud=false) {
  translate([px, py, 0]) {
    translate([0, 0, -BOSS_H])
      difference() {
        cylinder(d=BOSS_D, h=BOSS_H, $fn=24);
        if (!stud)
          translate([0, 0, -0.1])
            cylinder(d=SCREW_D * 0.7, h=BOSS_H + 0.2, $fn=18);
      }
    if (stud) {
      cylinder(r=STUD_R, h=STUD_H, $fn=24);
      translate([0, 0, STUD_H])
        sphere(r=STUD_R, $fn=24);
    }
  }
}

// ═══════════════════════════════════════════════════════════════════════
// Public module
// ═══════════════════════════════════════════════════════════════════════

module fpc_adapter(fpc_yp=FPC_YP, fpc_yn=FPC_YN) {

  // ── Visual geometry (preview only) ──────────────────────────────────
  if ($preview) {
    color("darkgray", 0.85) {
      difference() {
        _pcb_shape(PCB_T);
        for (xi = [HOLE_MX, PCB_W - HOLE_MX])
          for (yi = [HOLE_MY, PCB_H - HOLE_MY])
            translate([xi, yi, -0.1])
              cylinder(d=HOLE_D, h=PCB_T + 0.2, $fn=24);
      }

      // Connector A (Y+ edge, FPC exits +Y)
      translate([CON_CX - CON_W/2, CON_A_Y1, PCB_T])
        cube([CON_W, CON_D, CON_H]);
      if (fpc_yp > 0)
        translate([CON_CX - FPC_W/2, PCB_H, PCB_T + (CON_H - FPC_T)/2])
          cube([FPC_W, fpc_yp, FPC_T]);

      // Connector B (Y- edge, FPC exits -Y)
      translate([CON_CX - CON_W/2, CON_B_Y0, PCB_T])
        cube([CON_W, CON_D, CON_H]);
      if (fpc_yn > 0)
        translate([CON_CX - FPC_W/2, -fpc_yn, PCB_T + (CON_H - FPC_T)/2])
          cube([FPC_W, fpc_yn, FPC_T]);
    }
  }

  // ── Mounting bosses (always — structural geometry for host part) ─────
  color("#004B49") {
    _adapt_boss(HOLE_MX,          HOLE_MY,          stud=true);
    _adapt_boss(PCB_W - HOLE_MX,  PCB_H - HOLE_MY,  stud=true);
    _adapt_boss(HOLE_MX,          PCB_H - HOLE_MY,   stud=false);
    _adapt_boss(PCB_W - HOLE_MX,  HOLE_MY,           stud=false);
  }
}

// Standalone render
fpc_adapter(fpc_yp=FPC_YP, fpc_yn=FPC_YN);