epaper_door_case/hat.scad

// ============================================================
//  Button Extension Hat — development scratch file
//  Mirrors the +Y wall button-hole geometry from cpu_case.scad
// ============================================================
use <ee04.scad>

// Parameters copied from cpu_case.scad
WALL    = 2.0;   // wall thickness (depth of hole)
BTN_CX  = [48.4, 39.1, 29.8, 20.4];   // PCB-relative button X centres
BTN_CZ  = 3.85;  // button centre height above PCB bottom (calibrated)
PCB_W   = 41.22; // board width (Y axis)

// Wall section dimensions (just enough context around one hole)
WALL_W = 20;
WALL_H = 16;

HOLE_CX = WALL_W / 2;
HOLE_CZ = WALL_H / 2;

/* [Physical button] */
BTN_ACTUATOR_D = 2.0;   // measured button actuator diameter (<2 mm on EE04)

/* [Slip fit — SLA resin] */
SLIP_CLEAR = 0.15;   // radial clearance per side; SLA tolerances are tight so 0.15 gives easy slip without slop

/* [Plunger] */
PLUNGER_D = BTN_ACTUATOR_D;             // body and head diameter — matches button actuator
HOLE_D    = PLUNGER_D + 2 * SLIP_CLEAR; // wall cutout — slip fit around plunger body
FLANGE_D  = 2.9;                         // retention flange OD — keep current value
FLANGE_T  = 1.2;                         // flange thickness (axial)
HEAD_H    = 1.5;                         // how far head protrudes past exterior wall face

/* [Rest clearance] */
CLR_YP_CONTACT = 1.565;  // calibrated: plunger tip just touches button at this value
REST_CLEAR     = 0.40;   // axial gap added so a slightly thick print doesn't pre-press button at rest
CLR_YP         = CLR_YP_CONTACT + REST_CLEAR;

// Plunger — origin at hole centre on the interior wall face (y=0).
// At rest: flange front face flush with interior wall face; button spring holds it there.
module plunger() {
  color("orange") union() {
    // Body: runs from flange back face through wall to back of head
    translate([0, -FLANGE_T, 0])
      rotate([-90, 0, 0])
        cylinder(d = PLUNGER_D, h = FLANGE_T + WALL + HEAD_H, $fn = 32);

    // Inner flange: sits inside the case, stops plunger escaping outward
    translate([0, -FLANGE_T, 0])
      rotate([-90, 0, 0])
        cylinder(d = FLANGE_D, h = FLANGE_T, $fn = 32);

    // Outer head: finger-press cap proud of exterior wall face
    translate([0, WALL, 0])
      rotate([-90, 0, 0])
        cylinder(d = PLUNGER_D, h = HEAD_H, $fn = 32);
  }
}

// Wall section: positive Y face is the exterior (matching cpu_case +Y exterior)
difference() {
  cube([WALL_W, WALL, WALL_H]);

  translate([HOLE_CX, WALL + 0.1, HOLE_CZ])
    rotate([90, 0, 0])
      cylinder(d = HOLE_D, h = WALL + 0.2, $fn = 32);
}

// Plunger at rest — flange flush with interior wall face
translate([HOLE_CX, 0, HOLE_CZ]) plunger();

// EE04 board — aligned so BTN_CX[0] lines up with HOLE_CX and
// BTN_CZ lines up with HOLE_CZ; PCB +Y edge sits CLR_YP behind interior wall face.
translate([
  HOLE_CX - BTN_CX[0],
  -(PCB_W + CLR_YP),
  HOLE_CZ - BTN_CZ
]) EE04();