Add parametric 3D-printable enclosure (OpenSCAD)

A printable reimagining of the wooden Kidsbox: rectangular cabinet with two
front speakers, removable top lid (NFC tag rests there, reader mounts beneath),
and swappable speaker mounts.

- kidsbox.scad: master model + part dispatcher (body/lid/speaker_adapter/grill)
- params.scad: all tunable dimensions in one place
- lib.scad: helper modules (rounded shell, bosses, bolt circles)
- Fixed front-panel speaker interface + swappable adapter so any driver fits
  by printing a new adapter (edit spk_* params, re-export)
- Internal mounts: 2x18650 cradle, ESP32-LyraT standoffs, RC522 under lid,
  3 buttons on lid, USB/charge + power-switch side ports, back-wall vents
- Snap-in speaker grills
- Makefile to export STLs and render previews (headless via xvfb)
- Exported STLs and preview renders included
- Link enclosure from main README

Dimensions are sensible defaults from the reference photos and common parts;
README flags the fit-critical values to verify before mass-printing.

https://claude.ai/code/session_01MhAnh68DPNnTjcKqjNYDmk

README.md

@@ -63,6 +63,17 @@ Once connected to WiFi, open `http://<device-ip>` in a browser.
 
 ---
 
+## Enclosure
+
+A parametric, fully 3D-printable enclosure lives in [`enclosure/`](enclosure/) —
+a rectangular cabinet with two front speakers and a removable top where the NFC tag
+rests, with **swappable speaker mounts** so you can print an adapter to fit your
+drivers. See [`enclosure/README.md`](enclosure/README.md).
+
+![Enclosure](enclosure/img/hero.png)
+
+---
+
 ## Hardware
 
 ### Parts

enclosure/Makefile

@@ -0,0 +1,46 @@
+# Regenerate Kidsbox enclosure STLs and preview images from the OpenSCAD source.
+#
+#   make stl     export all printable STLs into stl/
+#   make img     render preview PNGs into img/   (needs a display or xvfb)
+#   make all     both
+#   make clean   remove generated STLs and images
+#
+# Override the renderer if openscad isn't on PATH:  make OPENSCAD=/path/to/openscad
+
+OPENSCAD ?= openscad
+SRC       = kidsbox.scad params.scad lib.scad
+PARTS     = body lid speaker_adapter grill
+
+STL_FILES = $(addprefix stl/,$(addsuffix .stl,$(PARTS)))
+
+# Software GL so it works headless under xvfb on a server.
+RENDER_ENV = LIBGL_ALWAYS_SOFTWARE=1 GALLIUM_DRIVER=llvmpipe
+XVFB       = xvfb-run -a -s "-screen 0 1280x960x24"
+IMGOPTS    = --viewall --autocenter --imgsize=1280,960 --colorscheme=Tomorrow
+
+.PHONY: all stl img clean
+all: stl img
+
+stl: $(STL_FILES)
+
+stl/%.stl: $(SRC)
+	@mkdir -p stl
+	$(OPENSCAD) -D 'part="$*"' -o $@ kidsbox.scad
+
+img: $(SRC)
+	@mkdir -p img
+	$(RENDER_ENV) $(XVFB) $(OPENSCAD) -D 'part="assembly"' -D 'explode=0' \
+		--camera=0,0,0,64,0,28,0 $(IMGOPTS) -o img/hero.png kidsbox.scad
+	$(RENDER_ENV) $(XVFB) $(OPENSCAD) -D 'part="assembly"' \
+		--camera=0,0,0,62,0,28,0 $(IMGOPTS) -o img/assembly.png kidsbox.scad
+	$(RENDER_ENV) $(XVFB) $(OPENSCAD) -D 'part="body"' \
+		--camera=0,0,0,60,0,25,0 $(IMGOPTS) -o img/body.png kidsbox.scad
+	$(RENDER_ENV) $(XVFB) $(OPENSCAD) -D 'part="lid"' \
+		--camera=0,0,0,60,0,200,0 $(IMGOPTS) -o img/lid_top.png kidsbox.scad
+	$(RENDER_ENV) $(XVFB) $(OPENSCAD) -D 'part="speaker_adapter"' \
+		--camera=0,0,0,60,0,20,0 $(IMGOPTS) -o img/speaker_adapter.png kidsbox.scad
+	$(RENDER_ENV) $(XVFB) $(OPENSCAD) -D 'part="grill"' \
+		--camera=0,0,0,55,0,20,0 $(IMGOPTS) -o img/grill.png kidsbox.scad
+
+clean:
+	rm -f stl/*.stl img/*.png

enclosure/README.md

@@ -0,0 +1,145 @@
+# Kidsbox — 3D-printable enclosure
+
+A parametric, fully 3D-printable reimagining of the original wooden Kidsbox.
+The design keeps the look of the hand-built box — a rectangular cabinet with two
+front-firing speakers and a removable top where the NFC tag rests — but makes the
+**speaker mount swappable** so you can print an adapter to fit whatever drivers you
+have on hand.
+
+![Assembly](img/hero.png)
+
+> Modelled in [OpenSCAD](https://openscad.org). Everything is driven by
+> [`params.scad`](params.scad) — change a few numbers, re-export, and print.
+
+---
+
+## What's in the box
+
+| Part | Qty | File | Notes |
+|---|---|---|---|
+| Body / cabinet | 1 | `stl/body.stl` | Shell with all internal mounts |
+| Lid | 1 | `stl/lid.stl` | Buttons + NFC reader mount underneath |
+| Speaker adapter | 2 | `stl/speaker_adapter.stl` | **Swappable** — print to fit your driver |
+| Speaker grill | 2 | `stl/grill.stl` | Snaps into the sound opening |
+
+The body carries mounts for everything else:
+
+- **2× 18650 battery holder** — open-top cradle with retaining lips (`batt_*` params)
+- **ESP32-LyraT v4.3** — four floor standoffs (`lyrat_*` params)
+- **RC522 NFC reader** — pocket on the lid underside, so a tag placed on top reads
+  through the thin (`lid_t = 2.4 mm`) PLA window
+- **3 buttons** (vol−, play/pause, vol+) — 12 mm holes in a row near the lid's front edge
+- **Speaker interface** — a fixed bolt pattern the swappable adapters mount to
+- **Side ports** — USB/charging cutout and a power-switch hole
+- **Vents** on the back wall
+
+| Body | Lid (underside) |
+|---|---|
+| ![Body](img/body.png) | ![Lid](img/lid.png) |
+
+---
+
+## Printing
+
+| Setting | Recommendation |
+|---|---|
+| Material | PLA or PETG (PLA is fine; keep metal away from the NFC window) |
+| Layer height | 0.2 mm |
+| Walls / perimeters | 3+ |
+| Infill | 15–20 % |
+| Supports | **Body:** none (print open-side up). **Lid:** none. **Adapter/Grill:** none. |
+| Orientation | Body open-top up; lid top-face down; adapter & grill flat |
+
+The body is ~190 × 115 × 110 mm, so it fits a 220 × 220 bed (Ender-3 class) and larger.
+
+---
+
+## Assembly
+
+1. **Speakers** → bolt each driver to a `speaker_adapter` using the adapter's inner
+   screw holes, then bolt the adapter to the four bosses inside the front wall (M3).
+2. **Grills** → press a `grill` into each sound opening from the front.
+3. **Electronics** → screw the ESP32-LyraT onto the floor standoffs; drop the 18650
+   holder into the cradle; route the USB/charge lead to the side cutout.
+4. **NFC reader** → screw the RC522 to the four posts under the lid.
+5. **Buttons** → fit the three 12 mm momentary switches into the lid holes.
+6. **Close up** → lower the lid (the lip locates it) and drive four M3 screws into the
+   corner bosses.
+
+---
+
+## Swapping speakers (the whole point)
+
+The front wall never changes — it has a **fixed interface**: a `spk_sound_d` opening
+and four bosses on a `spk_bolt_d` circle. Every speaker bolts to the box through an
+**adapter** that you print to match *your* driver. To make a new adapter, edit the
+adapter block in [`params.scad`](params.scad):
+
+```scad
+// ---- swappable speaker ADAPTER (edit for YOUR speaker) ----
+spk_frame_d      = 66;   // your speaker's outer frame diameter
+spk_cutout_d     = 58;   // cone clearance (a bit less than the cone surround)
+spk_screw_count  = 4;    // your speaker's mounting-hole count
+spk_screw_bolt_d = 60;   // your speaker's mounting-hole bolt circle
+```
+
+Then re-export just that part:
+
+```bash
+openscad -D 'part="speaker_adapter"' -o stl/speaker_adapter.stl kidsbox.scad
+```
+
+Leave the `spk_sound_d` / `spk_bolt_d` (panel) values alone and your new adapter will
+drop straight onto the same box.
+
+| Speaker adapter (swappable) | Grill |
+|---|---|
+| ![Adapter](img/speaker_adapter.png) | ![Grill](img/grill.png) |
+
+---
+
+## Regenerating everything
+
+```bash
+make stl     # export all STLs into stl/
+make img     # render preview PNGs (needs a display, or xvfb on a server)
+make all
+```
+
+Or one part at a time:
+
+```bash
+openscad -D 'part="body"'            -o stl/body.stl            kidsbox.scad
+openscad -D 'part="lid"'             -o stl/lid.stl             kidsbox.scad
+openscad -D 'part="speaker_adapter"' -o stl/speaker_adapter.stl kidsbox.scad
+openscad -D 'part="grill"'           -o stl/grill.stl           kidsbox.scad
+```
+
+---
+
+## ⚠️ Verify before mass-printing
+
+These dimensions are sensible defaults derived from the reference photos and common
+parts, **not** from calipers on your exact hardware. Before printing the whole set,
+print a quick test of the fit-critical features and confirm against your parts:
+
+- ESP32-LyraT mounting-hole rectangle (`lyrat_hole_dx`, `lyrat_hole_dy`)
+- RC522 mounting-hole rectangle (`bx`, `by` in the `rc522_mount()` module)
+- Your 18650 holder footprint (`batt_holder_*`)
+- Speaker frame/cone/bolt-circle (`spk_frame_d`, `spk_cutout_d`, `spk_screw_bolt_d`)
+
+A cheap way to validate the speaker fit is to print one `speaker_adapter` first.
+
+---
+
+## Files
+
+```
+enclosure/
+├── kidsbox.scad        master model + part dispatcher
+├── params.scad         all tunable dimensions  ← edit here
+├── lib.scad            helper modules
+├── Makefile            export/render targets
+├── stl/                exported STLs
+└── img/                rendered previews
+```

enclosure/kidsbox.scad

@@ -0,0 +1,275 @@
+// ============================================================================
+//  Kidsbox — parametric 3D-printable enclosure
+//  ---------------------------------------------------------------------------
+//  Open in OpenSCAD and set `part` (top-right) or export from the CLI:
+//
+//    openscad -D 'part="body"'            -o stl/body.stl            kidsbox.scad
+//    openscad -D 'part="lid"'             -o stl/lid.stl             kidsbox.scad
+//    openscad -D 'part="speaker_adapter"' -o stl/speaker_adapter.stl kidsbox.scad
+//    openscad -D 'part="grill"'           -o stl/grill.stl           kidsbox.scad
+//
+//  `part="assembly"` shows everything together (for preview only).
+//  All tunables live in params.scad.
+// ============================================================================
+
+include <params.scad>
+use     <lib.scad>
+
+part = "assembly";   // body | lid | speaker_adapter | grill | assembly
+
+// ---------------------------------------------------------------------------
+//  Front-panel speaker interface (the FIXED "mount for the speaker mount")
+// ---------------------------------------------------------------------------
+
+// Subtractive: the sound opening + an outer recess for the grill flange.
+module speaker_cut(cx, cz) {
+    translate([cx, 0, cz]) rotate([-90, 0, 0]) {
+        // sound opening straight through the front wall
+        translate([0, 0, -1]) cylinder(h = wall + 2, d = spk_sound_d);
+        // grill flange recess on the OUTSIDE face
+        translate([0, 0, -0.01]) cylinder(h = grill_t + 0.01, d = spk_sound_d + 8);
+    }
+}
+
+// Additive: 4 bosses on the INSIDE so a swappable adapter can bolt on.
+module speaker_bosses(cx, cz) {
+    translate([cx, 0, cz]) rotate([-90, 0, 0])
+        translate([0, 0, wall - 0.5])
+            bolt_circle(spk_bolt_d, spk_bolt_count, 45)
+                boss(spk_boss_d, spk_boss_h + 0.5, 2.6);   // self-tap for M3
+}
+
+// ---------------------------------------------------------------------------
+//  Button holes through the lid (row near the front edge)
+// ---------------------------------------------------------------------------
+module button_cuts() {
+    for (i = [0 : btn_count - 1]) {
+        x = box_w/2 + (i - (btn_count - 1) / 2) * btn_pitch;
+        translate([x, btn_row_y, box_h - 1])
+            cylinder(h = lid_t + 2, d = btn_d);
+    }
+}
+
+// ---------------------------------------------------------------------------
+//  Side ports: USB/charge (right wall) and power switch (left wall)
+// ---------------------------------------------------------------------------
+module side_ports() {
+    // USB on +X wall
+    translate([box_w - wall - 1, box_d * 0.30, usb_center_z])
+        cube([wall + 2, usb_w, usb_h], center = false);
+    // power switch on -X wall
+    translate([-1, box_d * 0.30, sw_center_z]) rotate([0, 90, 0])
+        cylinder(h = wall + 2, d = sw_d);
+}
+
+// ---------------------------------------------------------------------------
+//  Ventilation slots on the back wall (+Y)
+// ---------------------------------------------------------------------------
+module vents() {
+    total = (vent_count - 1) * (vent_slot_w + 4);
+    for (i = [0 : vent_count - 1]) {
+        x = box_w/2 - total/2 + i * (vent_slot_w + 4);
+        translate([x, box_d - wall - 1, box_h * 0.55])
+            cube([vent_slot_w, wall + 2, vent_slot_len]);
+    }
+}
+
+// ---------------------------------------------------------------------------
+//  Internal mounts
+// ---------------------------------------------------------------------------
+
+// Corner posts the lid screws into (fused into the wall corners, top-anchored).
+module lid_bosses() {
+    boss_len = lid_rim_h + 10;
+    for (sx = [lid_boss_inset, box_w - lid_boss_inset],
+         sy = [lid_boss_inset, box_d - lid_boss_inset])
+        translate([sx, sy, box_h - boss_len])
+            boss(lid_boss_d, boss_len, lid_screw_d - 0.6);  // self-tap
+}
+
+// ESP32-LyraT standoffs (board lies flat on the floor, toward the back).
+lyrat_cx = box_w/2;
+lyrat_cy = box_d - lyrat_d/2 - 10;
+module lyrat_standoffs() {
+    for (sx = [-lyrat_hole_dx/2, lyrat_hole_dx/2],
+         sy = [-lyrat_hole_dy/2, lyrat_hole_dy/2])
+        translate([lyrat_cx + sx, lyrat_cy + sy, floor_t])
+            boss(lyrat_standoff_d, lyrat_standoff_h, lyrat_screw_d);
+}
+
+// 2x 18650 battery cradle (open-top tray with end stops + clips), front-left.
+batt_cx = box_w/2;
+batt_cy = wall + batt_holder_d/2 + 4;
+module battery_cradle() {
+    ow = batt_holder_w + 2*batt_wall;
+    od = batt_holder_d + 2*batt_wall;
+    translate([batt_cx - ow/2, batt_cy - od/2, floor_t])
+    difference() {
+        cube([ow, od, batt_holder_h]);
+        // hollow pocket, open top
+        translate([batt_wall, batt_wall, batt_wall])
+            cube([batt_holder_w, batt_holder_d, batt_holder_h]);
+        // cable notch in the front wall of the cradle
+        translate([ow/2 - 6, -1, batt_holder_h - 8])
+            cube([12, batt_wall + 2, 10]);
+    }
+    if (batt_clip) {
+        // two retaining lips along the long sides
+        for (sy = [batt_cy - od/2 + batt_wall/2, batt_cy + od/2 - batt_wall/2])
+            translate([batt_cx - batt_holder_w/3, sy, floor_t + batt_holder_h])
+                rotate([0, 0, 0])
+                    cube([batt_holder_w*2/3, batt_wall, 2.5], center = false);
+    }
+}
+
+// ---------------------------------------------------------------------------
+//  BODY
+// ---------------------------------------------------------------------------
+module body() {
+    spk_l = box_w/2 - spk_spacing/2;
+    spk_r = box_w/2 + spk_spacing/2;
+
+    difference() {
+        union() {
+            shell([box_w, box_d, box_h], corner_r, wall, floor_t);
+            speaker_bosses(spk_l, spk_center_z);
+            speaker_bosses(spk_r, spk_center_z);
+            lid_bosses();
+            lyrat_standoffs();
+            battery_cradle();
+        }
+        speaker_cut(spk_l, spk_center_z);
+        speaker_cut(spk_r, spk_center_z);
+        side_ports();
+        vents();
+    }
+}
+
+// ---------------------------------------------------------------------------
+//  LID  (NFC reader sits underneath; print thin-side up)
+// ---------------------------------------------------------------------------
+
+// RC522 pocket posts on the lid underside.
+module rc522_mount() {
+    // board centred, posts hang DOWN from the lid underside (local -Z here)
+    bx = 54; by = 34;  // RC522 mounting-hole rectangle (verify)
+    for (sx = [-bx/2, bx/2], sy = [-by/2, by/2])
+        translate([sx, sy, -8])
+            cylinder(h = 8, d = 6);
+    // pilot holes
+    for (sx = [-bx/2, bx/2], sy = [-by/2, by/2])
+        translate([sx, sy, -8.5])
+            cylinder(h = 9, d = 2.4);
+}
+
+module lid() {
+    difference() {
+        union() {
+            // top plate sitting on the wall tops
+            translate([box_w/2, box_d/2, box_h])
+                linear_extrude(lid_t)
+                    rrect(box_w, box_d, corner_r);
+            // locating lip dropping into the interior
+            translate([box_w/2, box_d/2, box_h - lid_rim_h])
+                linear_extrude(lid_rim_h)
+                    difference() {
+                        rrect(inner_w - 2*fit, inner_d - 2*fit, max(0.1, corner_r - wall));
+                        rrect(inner_w - 2*fit - 2*lid_rim_t,
+                              inner_d - 2*fit - 2*lid_rim_t,
+                              max(0.1, corner_r - wall - lid_rim_t));
+                    }
+            // RC522 mount, centred under the lid
+            translate([box_w/2, box_d/2, box_h + lid_t]) rc522_mount();
+        }
+        // corner screw holes (countersunk) through the plate
+        for (sx = [lid_boss_inset, box_w - lid_boss_inset],
+             sy = [lid_boss_inset, box_d - lid_boss_inset]) {
+            translate([sx, sy, box_h - 0.5])
+                cylinder(h = lid_t + 1, d = lid_screw_d);
+            translate([sx, sy, box_h + lid_t - 1.4])
+                cylinder(h = 1.6, d1 = lid_screw_d, d2 = lid_screw_d + 3.5);
+        }
+        // button holes near the front edge
+        button_cuts();
+    }
+}
+
+// ---------------------------------------------------------------------------
+//  SWAPPABLE SPEAKER ADAPTER  (print one per speaker model)
+// ---------------------------------------------------------------------------
+module speaker_adapter() {
+    difference() {
+        union() {
+            cylinder(h = adapter_t, d = adapter_outer_d);
+            // frame seat ring raised on the back so the speaker locates
+            translate([0, 0, adapter_t])
+                ring(spk_frame_d + 6, spk_cutout_d, spk_frame_seat);
+        }
+        // cone clearance
+        translate([0, 0, -0.5]) cylinder(h = adapter_t + spk_frame_seat + 1, d = spk_cutout_d);
+        // speaker frame recess on the back
+        translate([0, 0, adapter_t - 0.01])
+            cylinder(h = spk_frame_seat + 0.02, d = spk_frame_d);
+        // mounting holes to the panel bosses (FIXED interface)
+        bolt_circle(spk_bolt_d, spk_bolt_count, 45)
+            translate([0, 0, -0.5]) cylinder(h = adapter_t + spk_frame_seat + 1, d = spk_bolt_hole_d);
+        // the speaker's OWN screw holes (swappable per model)
+        bolt_circle(spk_screw_bolt_d, spk_screw_count, 0)
+            translate([0, 0, -0.5]) cylinder(h = adapter_t + spk_frame_seat + 1, d = spk_screw_d);
+    }
+}
+
+// ---------------------------------------------------------------------------
+//  SPEAKER GRILL  (snaps into the sound opening)
+// ---------------------------------------------------------------------------
+module grill() {
+    r_out = spk_sound_d/2;
+    union() {
+        // outer flange that seats in the panel recess
+        ring(spk_sound_d + 8, spk_sound_d - 4, grill_t);
+        // friction lip into the hole
+        translate([0, 0, -grill_lip_h])
+            ring(spk_sound_d - 2*fit, spk_sound_d - 2*fit - 3, grill_lip_h + grill_t);
+        // concentric rings
+        for (i = [1 : grill_rings])
+            ring(2*r_out * i/(grill_rings+1) + 1.4,
+                 2*r_out * i/(grill_rings+1) - 1.4, grill_t);
+        // central hub
+        cylinder(h = grill_t, d = 6);
+        // radial spokes
+        for (i = [0 : grill_spokes - 1])
+            rotate([0, 0, i * 360/grill_spokes])
+                translate([0, -1.0, 0]) cube([r_out, 2.0, grill_t]);
+    }
+}
+
+// ---------------------------------------------------------------------------
+//  ASSEMBLY PREVIEW
+// ---------------------------------------------------------------------------
+explode = 45;   // lid lift for the exploded preview (0 = closed)
+
+module assembly() {
+    spk_l = box_w/2 - spk_spacing/2;
+    spk_r = box_w/2 + spk_spacing/2;
+    color("WhiteSmoke")  body();
+    color("Gainsboro")   translate([0, 0, explode]) lid();
+    for (cx = [spk_l, spk_r]) {
+        // adapter just inside the front wall
+        color("SteelBlue")
+            translate([cx, wall + adapter_t, spk_center_z]) rotate([90, 0, 0])
+                speaker_adapter();
+        // grill in the opening
+        color("DimGray")
+            translate([cx, grill_t, spk_center_z]) rotate([-90, 0, 0])
+                grill();
+    }
+}
+
+// ---------------------------------------------------------------------------
+//  DISPATCH
+// ---------------------------------------------------------------------------
+if      (part == "body")            body();
+else if (part == "lid")             lid();
+else if (part == "speaker_adapter") speaker_adapter();
+else if (part == "grill")           grill();
+else                                assembly();

enclosure/lib.scad

@@ -0,0 +1,53 @@
+// ============================================================================
+//  Kidsbox enclosure — helper modules
+// ============================================================================
+
+// A box with rounded VERTICAL edges only (flat top & bottom for clean FDM).
+//  size = [x, y, z], r = corner radius.
+module rbox(size, r) {
+    x = size[0]; y = size[1]; z = size[2];
+    hull() {
+        for (sx = [r, x - r], sy = [r, y - r])
+            translate([sx, sy, 0]) cylinder(h = z, r = r);
+    }
+}
+
+// Hollow shell: outer rbox minus inner rbox, open at the top (+Z).
+//  Floor thickness `ft`, wall `w`.
+module shell(size, r, w, ft) {
+    x = size[0]; y = size[1]; z = size[2];
+    difference() {
+        rbox([x, y, z], r);
+        translate([w, w, ft])
+            rbox([x - 2*w, y - 2*w, z - ft + 1], max(0.1, r - w));
+    }
+}
+
+// A screw boss (solid post with a pilot hole) standing in +Z.
+module boss(od, h, hole_d) {
+    difference() {
+        cylinder(h = h, d = od);
+        translate([0, 0, -0.5]) cylinder(h = h + 1, d = hole_d);
+    }
+}
+
+// A flat ring.
+module ring(od, id, h) {
+    difference() {
+        cylinder(h = h, d = od);
+        translate([0, 0, -0.5]) cylinder(h = h + 1, d = id);
+    }
+}
+
+// Bolt circle: place children at `count` points on diameter `d`.
+module bolt_circle(d, count, start = 0) {
+    for (i = [0 : count - 1])
+        rotate([0, 0, start + i * 360 / count])
+            translate([d/2, 0, 0]) children();
+}
+
+// A rounded-rectangle plate (2D) for linear_extrude.
+module rrect(x, y, r) {
+    hull() for (sx = [r, x - r], sy = [r, y - r])
+        translate([sx - x/2, sy - y/2]) circle(r = r);
+}

enclosure/params.scad

@@ -0,0 +1,96 @@
+// ============================================================================
+//  Kidsbox enclosure — parameters
+//  All dimensions in millimetres. Edit here, then re-export the STLs.
+//  See README.md for the export commands.
+// ============================================================================
+
+// ---- global print settings ------------------------------------------------
+$fn            = 64;     // facet count for curves (raise for final render)
+wall           = 3.0;    // shell wall thickness
+floor_t        = 3.0;    // bottom thickness
+corner_r       = 6.0;    // outer vertical-edge radius
+fit            = 0.30;   // general clearance for mating parts (per side)
+
+// ---- outer box dimensions (interior is derived) ---------------------------
+box_w          = 190;    // width  (X) — roughly one banana, per reference photo
+box_h          = 110;    // height (Z)
+box_d          = 115;    // depth  (Y)
+
+// derived interior
+inner_w        = box_w - 2*wall;
+inner_d        = box_d - 2*wall;
+inner_h        = box_h - floor_t;   // open-top shell, lid closes it
+
+// ---- lid -------------------------------------------------------------------
+lid_t          = 2.4;    // thin enough for 13.56 MHz NFC to read through PLA
+lid_rim_h      = 6.0;    // depth of the lip that drops into the box
+lid_rim_t      = 1.6;    // thickness of that lip
+lid_screw_d    = 3.2;    // M3 clearance
+lid_boss_d     = 9.0;    // corner screw-boss outer diameter
+lid_boss_inset = 9.0;    // boss centre inset from interior corner
+
+// ---- speaker panel interface (FIXED) --------------------------------------
+//  This is the standard "mount for the speaker mount". Every swappable
+//  speaker adapter bolts to THIS pattern, so the box never changes.
+spk_sound_d      = 66;   // sound opening through the front panel
+spk_bolt_d       = 80;   // bolt circle for the adapter screws
+spk_bolt_count   = 4;    // number of adapter screws
+spk_bolt_hole_d  = 3.2;  // M3 clearance through the panel
+spk_boss_d       = 8.0;  // screw boss diameter on the inside of the panel
+spk_boss_h       = 5.0;  // screw boss height (into the box)
+spk_spacing      = 94;   // centre-to-centre of the two speakers (X)
+spk_center_z     = 48;   // speaker centre height from the box floor (Z)
+
+// ---- swappable speaker ADAPTER (edit for YOUR speaker) ---------------------
+//  Print one adapter per speaker model. Defaults suit a common 3" driver.
+adapter_t        = 3.0;  // adapter plate thickness
+adapter_outer_d  = 88;   // outer diameter of the adapter disc
+spk_frame_d      = 66;   // speaker outer frame diameter (seat recess)
+spk_frame_seat   = 1.5;  // depth the frame sinks into the adapter
+spk_cutout_d     = 58;   // cone clearance hole through the adapter
+spk_screw_count  = 4;    // the SPEAKER's own mounting holes
+spk_screw_bolt_d = 60;   // bolt circle of the speaker's mounting holes
+spk_screw_d      = 3.0;  // speaker screw clearance
+
+// ---- speaker grill (snaps into the sound opening) -------------------------
+grill_t          = 2.4;  // grill face thickness
+grill_rings      = 3;    // number of concentric rings
+grill_spokes     = 6;    // number of radial spokes
+grill_lip_h      = 5.0;  // snap lip depth into the sound hole
+grill_standoff   = 3.0;  // gap the grill holds off the cone
+
+// ---- buttons (top lid, row near the front edge) ---------------------------
+//  Kept off the front face (which stays clean like the reference box) and
+//  clear of the central NFC reader, which sits under the lid centre.
+btn_d            = 12.2; // panel hole for a 12 mm momentary switch
+btn_count        = 3;    // vol-, play/pause, vol+
+btn_pitch        = 26;   // spacing between buttons along X
+btn_row_y        = 18;   // distance of the button row from the front wall
+
+// ---- side ports ------------------------------------------------------------
+usb_w            = 12;   // micro-USB / charge access cutout (W)
+usb_h            = 7;    // (H)
+usb_center_z     = 22;   // height of the port from the floor
+sw_d             = 7;    // power slide-switch hole diameter
+sw_center_z      = 22;
+
+// ---- ESP32-LyraT v4.3 mount (verify against your board) -------------------
+lyrat_w          = 99;   // board long edge
+lyrat_d          = 57;   // board short edge
+lyrat_hole_dx    = 92;   // mounting-hole rectangle, long axis  (VERIFY)
+lyrat_hole_dy    = 50;   // mounting-hole rectangle, short axis (VERIFY)
+lyrat_standoff_h = 6;    // standoff height off the floor
+lyrat_standoff_d = 6;    // standoff outer diameter
+lyrat_screw_d    = 2.6;  // self-tap for M2.5/M3
+
+// ---- 2x 18650 battery holder cradle ---------------------------------------
+batt_holder_w    = 78;   // typical 2-cell holder footprint (X)
+batt_holder_d    = 39;   // (Y)
+batt_holder_h    = 21;   // (Z)
+batt_wall        = 2.0;  // cradle wall
+batt_clip        = true; // add retaining clips
+
+// ---- ventilation -----------------------------------------------------------
+vent_slot_w      = 3;
+vent_slot_len    = 28;
+vent_count       = 5;