epaper_door_case/cpu_case.scad

// ============================================================
//  XIAO ePaper Display Board EE04 — 3D-Printed Case
//  OpenSCAD parametric model
// ============================================================
use <ee04.scad>
use <epd_case.scad>

/* [Preview] */
SHOW_BOARD    = true;
SHOW_LID      = true;
SHOW_BASE     = true;
SHOW_PLUNGERS = true;
SHOW_BATTERY  = true;
SHOW_EPD_CASE = true;
EXPLODE       = 70;      // mm to pull lid out in Y- for inspection (try 40)

/* [Board Dimensions — from EE04 STL] */
PCB_L = 80.00;   // board length  (case_x axis)
PCB_W = 41.22;   // board width   (case_y axis)
PCB_T =  1.93;   // PCB thickness

// Component heights measured from PCB bottom face:
COMP_MAX_Z  = 7.29;   // tallest component (XIAO module)
COMP_SIDE_Z = 3.82;   // tallest component on +Y wall (buttons, USB-C)

/* [Sliding Lid] */
LID_T       =  1.5;   // lid ceiling thickness
FLANGE_H    =  3.0;   // Z height of retention flanges (base + lid); drives lid placement and Y- wall step
FLANGE_W    =  FLANGE_H * tan(30);   // flange width — 30° from vertical (60° from horizontal), printable without support
SLIDE_CLEAR =  0.40;  // clearance between flange/rib and groove/channel on all mating faces (0.4 mm suits typical FDM tolerances)

// ---- Y- edge: FPC connector — notch in lid Y+ stop rib ----
// FPC_NOTCH_W and FPC_SLOT_W match the Z- face opening of epd_case:
//   _fpc_xw = 12.5 + 5.0 = 17.5 mm (cable + 2.5 mm clearance per side)
//   slot Y-extent at z=0: sqrt(_fpc_ro² − (FPC_BEND_R−WALL)²) ≈ 4.1 mm
//   with epd_case defaults: bend_r=4, wall=2, fpc_t=0.3, tol=0.3 → _fpc_ro=4.6
FPC_NOTCH_W =  17.5;   // = _fpc_xw in epd_case (cable 12.5 + 2×2.5 mm clearance)
FPC_U_T     = LID_T;   // U-rib arm and bar thickness
FPC_SLOT_W  =   4.1;   // ≈ sqrt(_fpc_ro²−(FPC_BEND_R−WALL)²) at epd_case z=0

// epd_case reference values for alignment (must match epd_case.scad)
_EPD_CASE_W      = 130.0;   // case_w in epd_case (DISP_W+2×TOL+2×WALL = 125.4+0.6+4)
_EPD_CASE_D      = 108.14;  // case_d in epd_case (max(cav_d+WALL+BEZEL_Y, _bend_my+WALL))
_EPD_FPC_SLOT_CX =  65.98;  // _fpc_x1 + _fpc_xw/2 in epd_case (slot X centre)
_EPD_FPC_SLOT_Y  = 102.0;   // BEZEL_Y + DISP_D in epd_case (slot Y- edge)

/* [Cutout Positions — from STL geometry, PCB-origin-relative] */

// ---- +Y wall: Sliding power switch ----
// TODO: measure actual switch body dimensions from STL (as done for USB-C) before next print
PWR_CX      =  10.3;   // PCB-relative case_x centre
PWR_W       =   5.0;   // slot width
PWR_H       =   2.5;   // slot height
PWR_CZ      =   3.8;   // height above PCB bottom
PWR_COVER_T =   0.6;   // exterior skin over switch pocket (switch not user-accessible)

// ---- +Y wall: USB-C port ----
USBC_CX         =  65.65;
USBC_W          =   9.0;   // port body width from STL
USBC_H          =   3.22;  // port body height from STL
USBC_CZ         =   4.31;
USBC_CBL_CLEAR  =   1.5;   // added per side for cable plug + routing clearance

// ---- +Y wall: 3× user buttons + 1× reset ----
BTN_CX      = [48.4, 39.075, 29.725, 20.425];   // PCB-relative case_x centres
BTN_D       =   2.3;   // HOLE_D from hat.scad: PLUNGER_D(2.0) + 2×SLIP_CLEAR(0.15)
BTN_CZ      =   3.85;

/* [Plunger] */
PLUNGER_D  =  2.0;   // body and head diameter — matches button actuator
FLANGE_D   =  2.9;   // retention flange OD
FLANGE_T   =  1.2;   // flange thickness (axial)
PLUNGER_HEAD_H =  1.5;   // exterior head protrusion past wall face

/* [Case Parameters] */
WALL          =  2.0;   // wall thickness
FLOOR         =  2.0;   // base floor thickness (thicker for thread engagement)
CORNER_R      =  2.5;   // XY corner fillet radius
SCREW_D       =  3.2;   // M3 tap drill diameter
BOSS_D        =  6.0;   // PCB standoff boss outer diameter
BOSS_H        =  2.0;   // standoff boss height; PCB bottom sits flush on boss top

/* [Locating Studs] */
STUD_CLEAR  =  0.10;   // radial clearance per side — close (non-interference) fit in SLA resin
STUD_H      =  PCB_T + 1.0;   // stud cylinder height above boss top: through PCB + 1 mm proud
STUD_R      =  (SCREW_D - 2*STUD_CLEAR) / 2;   // stud pin radius (= cylinder + dome radius)

/* [PCB Standoff Positions — relative to PCB origin] */
PCB_BOSS_X1   =  2.5;
PCB_BOSS_X2   =  PCB_L - 2.5;
PCB_BOSS_Y1   =  2.5;
PCB_BOSS_Y2   =  PCB_W - 2.5;

/* [Interior Clearances — PCB edge to interior wall face] */
CLR_XN   =   2.0;   // X- side
CLR_XP   =  44.0;   // X+ side — sized so OUT_L == _EPD_CASE_W (130 − 2×WALL − CLR_XN − PCB_L)
CLR_YN   =  15.0;   // Y- side (FPC routing; lid inserts from here)
CLR_YP   =   1.77;  // Y+ side: calibrated contact(1.565) + rest clearance(0.20)
CLR_LID  =   3.5;   // from tallest component top to lid underside
BATT_W   =  34.5;   // 603449 LiPo width  (X)
BATT_D   =  51.0;   // 603449 LiPo depth  (Y)
BATT_T   =   6.3;   // 603449 LiPo thickness (Z)
CLR_BATX =   1.5;   // battery X clearance from X+ wall
CLR_BATY =   1.5;   // battery Y clearance from Y+ wall

/* [Computed] */
PCB_Z    = FLOOR + BOSS_H;

// Base inner height: floor to lid underside ≈ BASE_H (flange rests on groove floor)
BASE_INNER_H = BOSS_H + COMP_MAX_Z + CLR_LID;
BASE_H       = FLOOR + BASE_INNER_H;

PCB_OX   = WALL + CLR_XN;
PCB_OY   = WALL + CLR_YN;

CAV_L    = CLR_XN + PCB_L + CLR_XP;
CAV_W    = CLR_YN + PCB_W + CLR_YP;
OUT_L    = CAV_L + 2*WALL;
OUT_W    = CAV_W + 2*WALL;

LID_H     = FLANGE_H + LID_T;
LID_Y_LEN = CAV_W;   // flange length; lid Y+ end stops against Y+ interior wall

// FPC notch X centre — keeps lid notch aligned with epd_case slot when centred on lid
FPC_CX = OUT_L/2 - _EPD_CASE_W/2 + _EPD_FPC_SLOT_CX - PCB_OX;

// U-rib depth — derived so ceiling slot Y aligns with epd_case FPC slot Y
// (3 = hardcoded rib Y thickness in lid module)
FPC_U_DEPTH = FPC_U_T - WALL - 3 + (_EPD_CASE_D - _EPD_FPC_SLOT_Y);

// ============================================================
//  HELPERS
// ============================================================
module rounded_box(l, w, h, r) {
    hull()
        for (dx = [r, l-r], dy = [r, w-r])
            translate([dx, dy, 0]) cylinder(r=r, h=h, $fn=32);
}

// Standoff boss: screw variant has through-hole; stud variant has locating pin instead.
// Diagonal (X1,Y1)+(X2,Y2) → studs; (X1,Y2)+(X2,Y1) → screws.
module pcb_boss(px, py, stud=false) {
    translate([PCB_OX + px, PCB_OY + py, FLOOR]) {
        difference() {
            cylinder(d=BOSS_D, h=BOSS_H + 0.01, $fn=24);
            if (!stud)
                translate([0, 0, -0.1])
                    cylinder(d=SCREW_D * 0.7, h=BOSS_H + 0.2, $fn=18);
        }
        if (stud)
            translate([0, 0, BOSS_H]) {
                cylinder(r=STUD_R, h=STUD_H, $fn=24);
                translate([0, 0, STUD_H])
                    sphere(r=STUD_R, $fn=24);
            }
    }
}

// Button plunger — origin at hole centre on the interior wall face.
// At rest: flange flush with interior face, head proud of exterior face.
module plunger() {
    color("orange") union() {
        translate([0, -FLANGE_T, 0])
            rotate([-90, 0, 0])
                cylinder(d = PLUNGER_D, h = FLANGE_T + WALL + PLUNGER_HEAD_H, $fn = 32);
        translate([0, -FLANGE_T, 0])
            rotate([-90, 0, 0])
                cylinder(d = FLANGE_D, h = FLANGE_T, $fn = 32);
        translate([0, WALL, 0])
            rotate([-90, 0, 0])
                cylinder(d = PLUNGER_D, h = PLUNGER_HEAD_H, $fn = 32);
    }
}

// ============================================================
//  BASE
// ============================================================
module base() {
    color("#004B49") {
        difference() {
            rounded_box(OUT_L, OUT_W, BASE_H, CORNER_R);

            // Interior cavity (open top)
            translate([WALL, WALL, FLOOR])
                cube([CAV_L, CAV_W, BASE_H]);

            // ---- Boss screw holes through 50 % of floor (screw diagonal only) ----
            for (pos = [[PCB_BOSS_X1, PCB_BOSS_Y2], [PCB_BOSS_X2, PCB_BOSS_Y1]])
                translate([PCB_OX + pos[0], PCB_OY + pos[1], FLOOR * 0.5 - 0.1])
                    cylinder(d=SCREW_D * 0.7, h=FLOOR * 0.5 + 0.2, $fn=18);

            // ---- +Y wall cutouts ----

            // Sliding power switch pocket — closed exterior face, interior clearance only
            translate([PCB_OX + PWR_CX - PWR_W/2,
                       OUT_W - WALL - 0.1,
                       PCB_Z + PWR_CZ - PWR_H/2])
                cube([PWR_W, WALL - PWR_COVER_T + 0.1, PWR_H]);

            // USB-C slot
            translate([PCB_OX + USBC_CX - (USBC_W + 2*USBC_CBL_CLEAR)/2,
                       OUT_W - WALL - 0.1,
                       PCB_Z + USBC_CZ - (USBC_H + 2*USBC_CBL_CLEAR)/2])
                cube([USBC_W + 2*USBC_CBL_CLEAR, WALL + 0.2, USBC_H + 2*USBC_CBL_CLEAR]);

            // 4× button holes (3 user + 1 reset)
            for (bcx = BTN_CX)
                translate([PCB_OX + bcx,
                           OUT_W + 0.1,
                           PCB_Z + BTN_CZ])
                    rotate([90, 0, 0])
                        cylinder(d=BTN_D, h=WALL + 0.3, $fn=32);

            // ---- Y- wall step for lid flange clearance ----
            // Remove the full Y- wall above z=BASE_H-FLANGE_H-SLIDE_CLEAR so the lid
            // flanges can enter freely from Y-.
            translate([-0.1, -0.1, BASE_H - FLANGE_H - SLIDE_CLEAR])
                cube([OUT_L + 0.2, WALL + 0.2, FLANGE_H + SLIDE_CLEAR + 0.1]);
        }

        // Standoff bosses (added outside diff so cavity doesn't subtract them)
        pcb_boss(PCB_BOSS_X1, PCB_BOSS_Y1, stud=true);   // stud diagonal
        pcb_boss(PCB_BOSS_X2, PCB_BOSS_Y2, stud=true);   // stud diagonal
        pcb_boss(PCB_BOSS_X1, PCB_BOSS_Y2, stud=false);  // screw diagonal
        pcb_boss(PCB_BOSS_X2, PCB_BOSS_Y1, stud=false);  // screw diagonal
    }

    // Lid-retention flanges — right triangles, wide face flush with case top (z=BASE_H),
    // tip pointing down to (WALL, BASE_H-FLANGE_H). Hypotenuse faces down-into-cavity;
    // lid flanges slide underneath it for Z retention.
    color("#2C3863") {
        hull() {
            translate([WALL, WALL, BASE_H - 0.01])
                cube([FLANGE_W, CAV_W, 0.01]);
            translate([WALL, WALL, BASE_H - FLANGE_H])
                cube([0.01, CAV_W, 0.01]);
        }
        hull() {
            translate([OUT_L - WALL - FLANGE_W, WALL, BASE_H - 0.01])
                cube([FLANGE_W, CAV_W, 0.01]);
            translate([OUT_L - WALL - 0.01, WALL, BASE_H - FLANGE_H])
                cube([0.01, CAV_W, 0.01]);
        }
        // Y+ locking flanges — same angled profile as side flanges, in YZ plane;
        // split around FPC notch for cable clearance
        for (seg = [
            [WALL,                             PCB_OX + FPC_CX - FPC_NOTCH_W/2 - WALL],
            [PCB_OX + FPC_CX + FPC_NOTCH_W/2, OUT_L - WALL - (PCB_OX + FPC_CX + FPC_NOTCH_W/2)]
        ])
            hull() {
                translate([seg[0], OUT_W - WALL - FLANGE_W, BASE_H - 0.01])
                    cube([seg[1], FLANGE_W, 0.01]);
                translate([seg[0], OUT_W - WALL - 0.01, BASE_H - FLANGE_H])
                    cube([seg[1], 0.01, 0.01]);
            }
    }
}

// ============================================================
//  LID  (slide-on; enters from Y- face, closes toward Y+)
//  Print upside-down (ceiling on build plate).
//  z=0 = bottom of flanges; z=FLANGE_H = ceiling underside.
//  Flanges sit inside cavity and ride on base retention flange hypotenuses.
// ============================================================
module lid() {
    // Flanges: right triangles in XZ; hypotenuse at reciprocal angle to base retention flanges.
    // Wide vertical face at x=WALL+FLANGE_W (inner), tip at bottom-wall-face — same
    // (-FLANGE_W, -FLANGE_H) hypotenuse slope as base flanges so they mate when lid slides in.
    color("#2C3863") {
        // Left (X-) flange — stops at Y+ locking flange inner face
        hull() {
            translate([WALL + FLANGE_W - SLIDE_CLEAR - 0.01, 0, 0])
                cube([0.01, LID_Y_LEN - FLANGE_W + SLIDE_CLEAR, FLANGE_H - SLIDE_CLEAR]);
            translate([WALL + SLIDE_CLEAR, 0, -0.005])
                cube([0.01, LID_Y_LEN - FLANGE_W + SLIDE_CLEAR, 0.01]);
        }
        // Right (X+) flange — stops at Y+ locking flange inner face
        hull() {
            translate([OUT_L - WALL - FLANGE_W + SLIDE_CLEAR, 0, 0])
                cube([0.01, LID_Y_LEN - FLANGE_W + SLIDE_CLEAR, FLANGE_H - SLIDE_CLEAR]);
            translate([OUT_L - WALL - SLIDE_CLEAR - 0.01, 0, -0.005])
                cube([0.01, LID_Y_LEN - FLANGE_W + SLIDE_CLEAR, 0.01]);
        }

        // Interior ribs — 2 mm wide
        translate([WALL + FLANGE_W - SLIDE_CLEAR, 0, 0])
            cube([2.0, LID_Y_LEN - FLANGE_W + SLIDE_CLEAR, FLANGE_H]);
        translate([OUT_L - WALL - FLANGE_W + SLIDE_CLEAR - 2.0, 0, 0])
            cube([2.0, LID_Y_LEN - FLANGE_W + SLIDE_CLEAR, FLANGE_H]);

        // Y+ locking flanges — angled wedge matching side-flange profile; split around FPC notch
        for (seg = [
            [FLANGE_W - SLIDE_CLEAR + 2.0,
             2+PCB_OX + FPC_CX - FPC_NOTCH_W/2 - (WALL + FLANGE_W - SLIDE_CLEAR + 2.0)],
            [PCB_OX + FPC_CX + FPC_NOTCH_W/2,
             OUT_L - FLANGE_W + SLIDE_CLEAR - 2.0 - (PCB_OX + FPC_CX + FPC_NOTCH_W/2)]
        ]) {
            hull() {
                translate([seg[0], LID_Y_LEN - FLANGE_W + SLIDE_CLEAR - 0.01, 0])
                    cube([seg[1], 0.01, FLANGE_H - SLIDE_CLEAR]);
                translate([seg[0], LID_Y_LEN - SLIDE_CLEAR - 0.01, -0.005])
                    cube([seg[1], 0.01, 0.01]);
            }
            // Backing rib — 2 mm deep on cavity face of flange, matches side-rib style
            translate([seg[0], LID_Y_LEN - FLANGE_W + SLIDE_CLEAR - 2.0, 0])
                cube([seg[1], 2.0, FLANGE_H]);
        }
    }

    color("#004B49")
    difference() {
        union() {
            // Ceiling plate — matches base footprint (OUT_L × OUT_W) with CORNER_R rounding
            if (!SHOW_EPD_CASE)
                translate([0, -WALL, FLANGE_H])
                    rounded_box(OUT_L, OUT_W, LID_T, CORNER_R);
            else
                translate([
                            OUT_L/2 - _EPD_CASE_W/2,
                            OUT_W - _EPD_CASE_D - WALL,
                            LID_T
            ])
                epd_case();

            // Y- lip — same rounded_box profile clipped to the Y- wall zone so the
            // lip corners match the base exterior corners
            intersection() {
                translate([0, -WALL, -SLIDE_CLEAR])
                    rounded_box(OUT_L, OUT_W, FLANGE_H + SLIDE_CLEAR, CORNER_R);
                translate([-0.1, -WALL - 0.1, -SLIDE_CLEAR - 0.1])
                    cube([OUT_L + 0.2, WALL + 0.2, FLANGE_H + SLIDE_CLEAR + 0.2]);
            }
        }

        // FPC cable slot — from Y+ face of U-rib bottom bar, FPC_SLOT_W toward Y+
        translate([PCB_OX + FPC_CX - FPC_NOTCH_W/2,
                   LID_Y_LEN - 3 - FPC_U_DEPTH + FPC_U_T,
                   FLANGE_H - 0.1])
            cube([FPC_NOTCH_W, FPC_SLOT_W, LID_T + 0.2]);
    }
}

// ============================================================
//  BOARD PLACEMENT
//  EE04() XY-normalises the STL (board left/front at origin).
//  +1.925 corrects for STL native Z (PCB bottom at Z=−1.925) so
//  the PCB bottom face lands exactly at PCB_Z.
// ============================================================
module stl_board() {
    translate([PCB_OX, PCB_OY, PCB_Z])
        EE04();
}

module battery() {
    if ($preview)
        color("darkgray", 0.85)
            translate([CAV_L - BATT_W - CLR_BATX,
                       CAV_W - BATT_D - CLR_BATY,
                       FLOOR + 0.01])
                cube([BATT_W, BATT_D, BATT_T]);
}

// ============================================================
//  ASSEMBLY
// ============================================================
if (SHOW_BASE)  base();

if (SHOW_BATTERY) battery();

if (SHOW_LID)
    translate([0,
               WALL - EXPLODE,
               BASE_H - FLANGE_H])
        lid();

if (SHOW_BOARD && $preview) stl_board();

if (SHOW_PLUNGERS)
    for (bcx = BTN_CX)
        translate([PCB_OX + bcx, OUT_W - WALL, PCB_Z + BTN_CZ])
            plunger();