A nightstand noise generator based on M5Stack Atom Echo and integrating with Home Assistant
enclosure: all hardware on the baseplate, snap-fit cover
Reorganized so the bottom plate is the structural foundation and the
chassis ("cover") is purely cosmetic. Cover comes off without tools,
exposing all internals at once.
* Speaker mounts to four tall posts on the bottom plate (60 mm M3
pattern), with self-tap pilots at the post tops. No more screw holes
through the cover's top panel. Foam sealing, if it turns out to be
needed, becomes a foam donut on top of the speaker frame compressed
against the cover underside during assembly.
* USB cable routes internally. The connector lives on the Atom inside
the chamber; cable threads through a printed strain-relief tunnel
a few cm in front of the back wall and exits through a small notch
at the bottom of the back wall, matched by a notch in the plate's
back edge so the exit sits flush with the bottom of the unit.
* Cover retention is snap-fit. Four tabs on the plate carry hemi-
spherical bumps that catch in detent recesses on the chassis inner
walls. M3 screws and bosses are gone.
Post height, cable diameter, and snap-bump diameter are param-tunable
guesses to be dialed in after a test print.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
+253
-162
+86
-67
enclosure/lib/params.scad
+86
-67
enclosure/lib/params.scad
···
1
1
// Sound machine enclosure — shared dimensions.
2
2
// Units: mm. Edit here; everything else derives.
3
+
//
4
+
// Design principle: all internal hardware mounts to the bottom plate.
5
+
// The chassis ("cover") just drops on top, captured by snap-fit tabs.
6
+
// No tools required to open or close the unit.
3
7
4
8
// ============================================================
5
9
// Atom Echo (M5Stack C008-C)
···
16
20
atom_usb_h_native = 7;
17
21
18
22
// Bottom-face male HY2.0-4P GROVE connector.
19
-
// Sticks down from the body; sits between the press-fit headers.
20
23
grove_body_w = 8;
21
24
grove_body_d = 4.5;
22
25
grove_body_h = 2.5;
23
26
24
27
// Bottom-face press-fit headers (the "Atom Stack" interface).
25
-
// 5-pin on one edge, 4-pin on the opposite edge. Pitch 2.54 mm.
26
28
header_pitch = 2.54;
27
29
header_left_pin_count = 5;
28
30
header_right_pin_count = 4;
29
-
header_edge_offset = 2.0; // body-edge to pin-row centerline (estimate)
31
+
header_edge_offset = 2.0;
30
32
31
33
// ============================================================
32
34
// MAX98357A I2S amp breakout (Adafruit 3006 / generic clone)
···
50
52
spk_magnet_clearance = 30; // air below baffle for magnet + breathing
51
53
52
54
// ============================================================
53
-
// Daughterboard — the small PCB the Atom presses onto.
54
-
// Carries the MAX98357A and the speaker terminals; sits on
55
-
// standoffs molded into the bottom plate.
55
+
// Daughterboard — protoboard the Atom presses onto.
56
56
// ============================================================
57
57
58
58
dboard_t = 1.6;
···
65
65
// Snooze cap + well
66
66
// ============================================================
67
67
68
-
// The cap is a wide pad covering most of the snooze zone — easy to
69
-
// find in the dark. The cap body passes through a through-hole in
70
-
// the top panel; a flange on its underside (wider than the hole)
71
-
// catches on the underside of the top panel as the up-stop. Down-
72
-
// stop is the Atom's tactile dome, which also acts as the return
73
-
// spring.
74
68
snooze_cap_w = 70;
75
69
snooze_cap_d = 28;
76
-
snooze_cap_h_above = 6; // how far the cap protrudes above the top surface
77
-
snooze_cap_wall_t = 1.5; // thin so the SK6812 LED diffuses through
78
-
snooze_cap_clearance = 0.4; // play between cap body and well walls
79
-
snooze_cap_travel = 1.5; // total cap travel from rest to fully pressed
70
+
snooze_cap_h_above = 6;
71
+
snooze_cap_wall_t = 1.5;
72
+
snooze_cap_clearance = 0.4;
73
+
snooze_cap_travel = 1.5;
80
74
81
-
// Captive flange on the underside of the cap — must be wider than
82
-
// the well opening so it catches on the underside of the top panel.
83
75
snooze_cap_flange_overhang = 3;
84
76
snooze_cap_flange_h = 2;
85
77
86
-
// Well opening in the top panel — derived from the cap.
87
78
snooze_well_w = snooze_cap_w + 2 * snooze_cap_clearance;
88
79
snooze_well_d = snooze_cap_d + 2 * snooze_cap_clearance;
89
80
···
91
82
// Speaker grille (in the rear portion of the top panel)
92
83
// ============================================================
93
84
94
-
grille_hole_d = 2.5;
95
-
grille_pitch = 5;
96
-
// Constrain the grille to the speaker's cone diameter — holes outside
97
-
// that radius hit the speaker's rigid frame and don't pass sound.
85
+
grille_hole_d = 2.5;
86
+
grille_pitch = 5;
98
87
grille_diameter = spk_cone_cutout;
99
88
100
89
// ============================================================
···
102
91
// ============================================================
103
92
104
93
wall_t = 3;
105
-
top_t = 4; // a touch thicker for rigidity around the speaker mount
94
+
top_t = 4;
106
95
bottom_t = 3;
107
96
108
-
// Subtle rounding on the chassis outer top + vertical edges. Bottom edge
109
-
// stays sharp so the part sits flat on the print bed (chassis prints
110
-
// open-bottom-down).
111
-
chassis_round_r = 1.5;
97
+
chassis_round_r = 1.5;
98
+
cap_round_r = 1.5;
99
+
cap_dome_h = 1.5;
100
+
snooze_well_corner_r = 1.5;
112
101
113
-
// Slight rounding on the visible (above-the-top-panel) portion of the
114
-
// snooze cap. Hidden portions stay sharp.
115
-
cap_round_r = 1.5;
116
-
117
-
// Spherical dome on top of the visible cap — center rises this far above
118
-
// the corners, so a sleepy hand finds the high point first.
119
-
cap_dome_h = 1.5;
120
-
121
-
// Rounded corner radius on the snooze well opening, matching the cap.
122
-
snooze_well_corner_r = 1.5;
123
-
124
-
// Top-panel layout (front to back, looking down at the unit):
102
+
// Top-panel layout (front to back, looking down):
125
103
// front_margin | snooze well | zone_gap | speaker grille | back_margin
126
104
front_margin = 8;
127
105
zone_gap = 6;
128
106
back_margin = 6;
129
107
130
-
// Internal volume.
131
-
inner_w = max(dboard_w + 8, spk_frame + 6); // whichever is wider
108
+
inner_w = max(dboard_w + 8, spk_frame + 6);
132
109
inner_d = front_margin + snooze_well_d + zone_gap + spk_frame + back_margin;
133
110
inner_h = max(spk_magnet_clearance + 4,
134
111
dboard_standoff_h + dboard_t + dboard_pin_h + atom_body_h + 3);
135
112
136
-
// Outer envelope.
137
113
outer_w = inner_w + 2 * wall_t;
138
114
outer_d = inner_d + 2 * wall_t;
139
-
outer_h = inner_h + top_t; // bottom is a separate plate; chassis is open-bottom
115
+
outer_h = inner_h + top_t;
116
+
117
+
// ============================================================
118
+
// Speaker mounting posts on the bottom plate.
119
+
// Speaker rests on top of the posts, M3 self-tap screws come down
120
+
// through the speaker's mounting tabs into the post tops. With the
121
+
// speaker thus mounted to the base, the cover panel above is purely
122
+
// cosmetic — no fasteners pass through it.
123
+
//
124
+
// Post height targets the speaker frame plate at ~22 mm above the
125
+
// bottom plate, leaving ~3 mm clearance below the cover for a foam
126
+
// donut between frame and cover underside. Re-tune `spk_post_h` once
127
+
// you've measured the actual cone protrusion / magnet depth on a
128
+
// physical unit.
129
+
// ============================================================
130
+
131
+
spk_post_h = 22;
132
+
spk_post_d = 6;
133
+
spk_post_pilot_d = 2.5;
140
134
141
135
// ============================================================
142
-
// USB-C cutout in the back wall.
143
-
// Aligned with the Atom Echo's USB-C port: vertically centered on the
144
-
// Atom body, which sits atop the daughterboard's pin headers.
145
-
// Slightly larger than the Atom's own cutout for plug clearance.
136
+
// USB-C cable: routed internally, exits through a small notch at the
137
+
// bottom of the back wall. A printed strain-relief tunnel on the
138
+
// bottom plate grips the cable so a tug doesn't transfer to the
139
+
// connector.
146
140
// ============================================================
147
141
148
-
usb_hole_w = 14;
149
-
usb_hole_h = 9;
142
+
cable_diameter = 4; // typical USB-C cable jacket OD
150
143
151
-
// Z of the bottom of the Atom body (measured from the inside floor of the
152
-
// chassis, which sits atop the bottom plate).
153
-
atom_z_bottom = dboard_standoff_h + dboard_t + dboard_pin_h;
154
-
// USB-C port centerline is vertically centered on the Atom body height.
155
-
usb_hole_cz = atom_z_bottom + atom_body_h / 2;
144
+
cable_notch_w = cable_diameter + 2;
145
+
cable_notch_h = cable_diameter + 2;
146
+
147
+
cable_clip_inner_w = cable_diameter + 0.4; // snug horizontal fit
148
+
cable_clip_inner_h = cable_diameter + 0.4; // snug vertical fit
149
+
cable_clip_wall_t = 1.5;
150
+
cable_clip_l = 8; // length along cable axis
151
+
cable_clip_y_from_back = 12; // from the back wall inside face
156
152
157
153
// ============================================================
158
-
// Bottom plate — separate part, screws onto the chassis from below.
154
+
// Snap-fit cover retention.
155
+
//
156
+
// Four tabs rise from the bottom plate's top face, one centered on
157
+
// each side. Each tab carries a small hemispherical bump near its
158
+
// top, which catches in a matching detent recess on the chassis
159
+
// inner wall. Drop the chassis on, hear the snap; pull straight up
160
+
// firmly to remove.
159
161
// ============================================================
160
162
161
-
bottom_plate_t = 3;
162
-
bottom_plate_screw_d = 3.4; // M3 clearance through the plate
163
-
bottom_plate_pilot_d = 2.5; // M3 self-tap pilot in the chassis boss (PLA)
164
-
bottom_plate_screw_inset = 5; // edge to screw centerline
165
-
bottom_plate_boss_d = 8; // OD of the screw bosses inside the chassis
166
-
bottom_plate_boss_h = 8; // height of bosses above the chassis open bottom
163
+
snap_tab_w = 14;
164
+
snap_tab_t = 2;
165
+
snap_tab_h = 8;
166
+
snap_tab_clearance = 0.3; // gap between tab and chassis inner wall
167
+
168
+
snap_bump_d = 2; // hemisphere diameter
169
+
snap_bump_inset_from_top = 1.5; // bump center below tab top
170
+
171
+
// Recess on the chassis inner wall — slightly larger than the bump
172
+
// for a positive click without binding.
173
+
snap_recess_w = snap_tab_w + 2;
174
+
snap_recess_h = snap_bump_d + 1;
175
+
snap_recess_d = snap_bump_d / 2 + 0.4;
176
+
// Vertical center of the recess in chassis coords (chassis open bottom = z=0).
177
+
snap_recess_cz = snap_tab_h - snap_bump_inset_from_top;
178
+
179
+
// ============================================================
180
+
// Bottom plate
181
+
// ============================================================
182
+
183
+
bottom_plate_t = 3;
184
+
185
+
// ============================================================
186
+
// Z reference for the snooze-cap plunger sizing.
187
+
// ============================================================
188
+
189
+
atom_z_bottom = dboard_standoff_h + dboard_t + dboard_pin_h;
167
190
168
191
// ============================================================
169
192
// Component placement (X centered; Y measured from the front wall inside)
170
193
// ============================================================
171
194
172
-
// Snooze well center, in chassis-internal coordinates (origin at front-left
173
-
// inside corner of the chamber).
174
195
snooze_well_cy = front_margin + snooze_well_d / 2;
175
-
176
-
// Speaker grille center.
177
-
spk_grille_cy = front_margin + snooze_well_d + zone_gap + spk_frame / 2;
196
+
spk_grille_cy = front_margin + snooze_well_d + zone_gap + spk_frame / 2;
+125
-45
enclosure/parts/bottom-plate.scad
+125
-45
enclosure/parts/bottom-plate.scad
···
1
-
// Bottom plate — closes the open-bottom chassis from below and carries
2
-
// the standoffs that hold the daughterboard.
1
+
// Bottom plate — the structural foundation of the unit. All internal
2
+
// hardware mounts here:
3
+
// * Daughterboard sits on 4 standoffs (front section).
4
+
// * Speaker rests on 4 tall posts at the 60 mm M3 pattern (rear
5
+
// section), with M3 self-tap screws coming down through its
6
+
// mounting tabs into the post tops.
7
+
// * USB cable threads through a strain-relief tunnel on its way out
8
+
// the back-bottom notch.
9
+
// The chassis ("cover") drops straight on top, captured by 4 snap-fit
10
+
// tabs around the perimeter.
3
11
//
4
-
// Coordinate system: same as the chassis. Origin at the bottom-front-left
5
-
// outer corner. The plate's top face sits at z=0 (i.e., flush with the
6
-
// chassis's open-bottom edge); the plate body extends downward to
7
-
// z=-bottom_plate_t.
12
+
// Coordinate system: same as the chassis. Origin at the bottom-front-
13
+
// left outer corner. The plate's top face sits at z=0; the plate body
14
+
// extends downward to z = -bottom_plate_t.
8
15
9
16
include <../lib/params.scad>
10
17
include <../lib/util.scad>
···
14
21
15
22
EPS = 0.05;
16
23
17
-
// Register tab dimensions — small bumps on the plate's top face that
18
-
// slide into the chassis cavity, locating the plate laterally during
19
-
// assembly before the screws are run home.
20
-
tab_w = 12; // length along the wall direction
21
-
tab_t = 2; // thickness perpendicular to the wall
22
-
tab_h = 2; // height above the plate top face
23
-
tab_clear = 0.3; // gap between the tab and the chassis inner wall
24
-
25
-
// Daughterboard sits in the front portion of the chamber, directly under
26
-
// the snooze well, with its center aligned to the snooze well center.
24
+
// Daughterboard sits in the front portion of the chamber, directly
25
+
// under the snooze well, with its center aligned to the well center.
27
26
dboard_cx = outer_w / 2;
28
27
dboard_cy = wall_t + snooze_well_cy;
29
28
29
+
// Speaker sits in the rear portion, aligned with the grille.
30
+
spk_cx = outer_w / 2;
31
+
spk_cy = wall_t + spk_grille_cy;
32
+
30
33
module bottom_plate() {
31
34
difference() {
32
35
// Plate body — rounded vertical corners to match the chassis,
···
34
37
translate([0, 0, -bottom_plate_t])
35
38
rounded_prism([outer_w, outer_d, bottom_plate_t], chassis_round_r);
36
39
37
-
// Screw clearance holes — 4 corners, matching the chassis bosses.
38
-
for (cx = [wall_t + bottom_plate_screw_inset,
39
-
outer_w - wall_t - bottom_plate_screw_inset])
40
-
for (cy = [wall_t + bottom_plate_screw_inset,
41
-
outer_d - wall_t - bottom_plate_screw_inset])
42
-
translate([cx, cy, -bottom_plate_t - EPS])
43
-
cylinder(h = bottom_plate_t + 2 * EPS,
44
-
d = bottom_plate_screw_d);
40
+
// Cable notch in the back edge of the plate, aligning with the
41
+
// chassis cable notch in the back wall — together they form a
42
+
// small rectangular hole flush with the bottom of the unit.
43
+
translate([(outer_w - cable_notch_w) / 2,
44
+
outer_d - wall_t - EPS,
45
+
-bottom_plate_t - EPS])
46
+
cube([cable_notch_w, wall_t + 2 * EPS, bottom_plate_t + 2 * EPS]);
45
47
}
46
48
47
49
// Daughterboard standoffs — 4 corners of the daughterboard footprint.
48
-
// Self-tapping into the daughterboard with M2 (preferred) or M2.5,
49
-
// depending on what holes get drilled in the daughterboard.
50
50
daughterboard_standoffs();
51
51
52
-
// Register tabs — locate the plate laterally inside the chassis
53
-
// cavity during assembly.
54
-
register_tabs();
55
-
}
52
+
// Speaker mounting posts — 4 at the 60 mm M3 pattern.
53
+
speaker_posts();
56
54
57
-
module register_tabs() {
58
-
inset = wall_t + tab_clear;
59
-
60
-
// Front + back tabs run parallel to the X axis.
61
-
for (cy = [inset, outer_d - inset - tab_t])
62
-
translate([(outer_w - tab_w) / 2, cy, 0])
63
-
cube([tab_w, tab_t, tab_h]);
55
+
// USB cable strain-relief tunnel near the back wall.
56
+
cable_clip();
64
57
65
-
// Left + right tabs run parallel to the Y axis.
66
-
for (cx = [inset, outer_w - inset - tab_t])
67
-
translate([cx, (outer_d - tab_w) / 2, 0])
68
-
cube([tab_t, tab_w, tab_h]);
58
+
// Snap-fit tabs that retain the chassis cover.
59
+
snap_tabs();
69
60
}
70
61
71
62
module daughterboard_standoffs() {
72
63
standoff_d = 5;
73
-
standoff_id = 1.6; // pilot for self-tapping M2
74
-
inset = 3; // distance from daughterboard edge to standoff center
64
+
standoff_id = 1.6;
65
+
inset = 3;
75
66
76
-
// Standoff top sits at z = dboard_standoff_h (so the daughterboard
77
-
// bottom face rests there).
78
67
for (sx = [dboard_cx - dboard_w / 2 + inset,
79
68
dboard_cx + dboard_w / 2 - inset])
80
69
for (sy = [dboard_cy - dboard_d / 2 + inset,
···
85
74
translate([sx, sy, -EPS])
86
75
cylinder(h = dboard_standoff_h + 2 * EPS, d = standoff_id);
87
76
}
77
+
}
78
+
79
+
module speaker_posts() {
80
+
p = spk_mount_pattern / 2;
81
+
82
+
for (sx = [-p, p])
83
+
for (sy = [-p, p])
84
+
difference() {
85
+
translate([spk_cx + sx, spk_cy + sy, 0])
86
+
cylinder(h = spk_post_h, d = spk_post_d);
87
+
translate([spk_cx + sx, spk_cy + sy, -EPS])
88
+
cylinder(h = spk_post_h + 2 * EPS, d = spk_post_pilot_d);
89
+
}
90
+
}
91
+
92
+
// A short rectangular tunnel for the USB cable. The cable threads
93
+
// through it during assembly; pulls on the cable transfer to the
94
+
// tunnel walls (and thus the bottom plate) instead of the connector.
95
+
module cable_clip() {
96
+
cy_center = outer_d - wall_t - cable_clip_y_from_back;
97
+
outer_w_l = cable_clip_inner_w + 2 * cable_clip_wall_t;
98
+
outer_h_l = cable_clip_inner_h + cable_clip_wall_t; // open at the bottom
99
+
100
+
translate([(outer_w - outer_w_l) / 2,
101
+
cy_center - cable_clip_l / 2,
102
+
0])
103
+
difference() {
104
+
cube([outer_w_l, cable_clip_l, outer_h_l]);
105
+
106
+
// Hollow the tunnel along the cable axis.
107
+
translate([cable_clip_wall_t,
108
+
-EPS,
109
+
0]) // open at z=0 so the cable can drop in from above
110
+
cube([cable_clip_inner_w,
111
+
cable_clip_l + 2 * EPS,
112
+
cable_clip_inner_h]);
113
+
}
114
+
}
115
+
116
+
// Four snap-fit tabs centered on each side of the cavity. Each carries
117
+
// a small hemispherical bump near its top that catches in a recess on
118
+
// the chassis inner wall.
119
+
module snap_tabs() {
120
+
inset = wall_t + snap_tab_clearance;
121
+
122
+
// Front (along front wall): tab oriented with its width along X,
123
+
// thickness along Y, bump on the +Y face? No — the chassis wall is
124
+
// at y < wall_t, so the bump should face -Y (toward the front
125
+
// wall's interior face, which is at y = wall_t).
126
+
// Actually: the front wall's INTERIOR face is at y = wall_t, on
127
+
// the +Y side from the wall. The tab sits inside the cavity at y =
128
+
// wall_t + snap_tab_clearance. The bump faces the front wall's
129
+
// interior, i.e., -Y. So bump goes on the -Y face of the tab.
130
+
snap_tab_oriented(
131
+
cx = (outer_w - snap_tab_w) / 2,
132
+
cy = inset,
133
+
size = [snap_tab_w, snap_tab_t, snap_tab_h],
134
+
bump_offset = [snap_tab_w / 2, 0, snap_tab_h - snap_bump_inset_from_top]
135
+
);
136
+
137
+
// Back wall.
138
+
snap_tab_oriented(
139
+
cx = (outer_w - snap_tab_w) / 2,
140
+
cy = outer_d - inset - snap_tab_t,
141
+
size = [snap_tab_w, snap_tab_t, snap_tab_h],
142
+
bump_offset = [snap_tab_w / 2, snap_tab_t, snap_tab_h - snap_bump_inset_from_top]
143
+
);
144
+
145
+
// Left wall.
146
+
snap_tab_oriented(
147
+
cx = inset,
148
+
cy = (outer_d - snap_tab_w) / 2,
149
+
size = [snap_tab_t, snap_tab_w, snap_tab_h],
150
+
bump_offset = [0, snap_tab_w / 2, snap_tab_h - snap_bump_inset_from_top]
151
+
);
152
+
153
+
// Right wall.
154
+
snap_tab_oriented(
155
+
cx = outer_w - inset - snap_tab_t,
156
+
cy = (outer_d - snap_tab_w) / 2,
157
+
size = [snap_tab_t, snap_tab_w, snap_tab_h],
158
+
bump_offset = [snap_tab_t, snap_tab_w / 2, snap_tab_h - snap_bump_inset_from_top]
159
+
);
160
+
}
161
+
162
+
module snap_tab_oriented(cx, cy, size, bump_offset) {
163
+
translate([cx, cy, 0]) {
164
+
cube(size);
165
+
translate(bump_offset)
166
+
sphere(d = snap_bump_d);
167
+
}
88
168
}
89
169
90
170
bottom_plate();
+42
-50
enclosure/parts/chassis.scad
+42
-50
enclosure/parts/chassis.scad
···
1
-
// Main printed chassis — 4 walls + integrated top panel, open at the bottom.
2
-
// The bottom plate (separate part) screws on from below and carries the
3
-
// daughterboard standoffs.
1
+
// Main printed chassis — 4 walls + integrated top panel, open at the
2
+
// bottom. Drops onto the bottom plate (where all hardware lives) and is
3
+
// retained by 4 snap-fit tabs that catch in the recesses on the inner
4
+
// walls. No fasteners; pull straight up firmly to remove.
4
5
//
5
6
// Coordinate system: origin at the bottom-front-left outer corner.
6
7
// +X = right, +Y = back, +Z = up.
···
19
20
// bottom so the part sits flat on the build plate.
20
21
rounded_box_top([outer_w, outer_d, outer_h], chassis_round_r);
21
22
22
-
// Inner cavity — open-bottom, so subtract a cube that extends
23
-
// through z=0 and stops at the underside of the top panel.
23
+
// Inner cavity — open-bottom.
24
24
translate([wall_t, wall_t, -EPS])
25
25
cube([inner_w, inner_d, inner_h + EPS]);
26
26
···
31
31
rounded_prism([snooze_well_w, snooze_well_d, top_t + 2 * EPS],
32
32
snooze_well_corner_r);
33
33
34
-
// Speaker grille — a circular field of small holes in the rear
35
-
// portion of the top panel, constrained to the cone diameter.
34
+
// Speaker grille — circular field of small holes, constrained
35
+
// to the cone diameter. Speaker now mounts to bottom-plate
36
+
// posts, so this is the only feature the cover contributes to
37
+
// the speaker; no M3 holes anywhere on the top panel.
36
38
speaker_grille();
37
39
38
-
// Speaker mounting holes — 4× M3 clearance, 60 mm square pattern,
39
-
// through the top panel.
40
-
speaker_mount_holes();
41
-
42
-
// USB-C cutout in the back wall.
43
-
translate([(outer_w - usb_hole_w) / 2,
40
+
// Cable notch in the back wall, at the bottom edge. The USB
41
+
// cable plugs into the Atom internally and exits here.
42
+
translate([(outer_w - cable_notch_w) / 2,
44
43
outer_d - wall_t - EPS,
45
-
usb_hole_cz - usb_hole_h / 2])
46
-
cube([usb_hole_w, wall_t + 2 * EPS, usb_hole_h]);
44
+
0])
45
+
cube([cable_notch_w, wall_t + 2 * EPS, cable_notch_h]);
47
46
48
-
// Bottom-plate screw holes — clearance through the chassis wall
49
-
// is unnecessary because the bottom plate screws into bosses
50
-
// (added below); subtract from those bosses instead.
51
-
bottom_plate_screw_holes();
47
+
// Snap-fit detent recesses on the inside of the four walls,
48
+
// matching the tabs on the bottom plate.
49
+
snap_recesses();
52
50
}
53
-
54
-
// Bottom-plate screw bosses, 4 corners inside the chassis.
55
-
bottom_plate_screw_bosses();
56
51
}
57
52
58
53
module speaker_grille() {
···
60
55
cy = wall_t + spk_grille_cy;
61
56
r = grille_diameter / 2;
62
57
63
-
// Hexagonal-ish grid clipped to a circle.
64
58
intersection() {
65
59
translate([cx - r, cy - r, outer_h - top_t - EPS])
66
60
cube([2 * r, 2 * r, top_t + 2 * EPS]);
···
68
62
union() {
69
63
for (xi = [-r : grille_pitch : r])
70
64
for (yi = [-r : grille_pitch : r]) {
71
-
// Stagger every other row by half-pitch for a nicer pattern.
72
65
xoff = (round(yi / grille_pitch) % 2 == 0) ? 0 : grille_pitch / 2;
73
66
px = cx + xi + xoff;
74
67
py = cy + yi;
···
80
73
}
81
74
}
82
75
83
-
module speaker_mount_holes() {
84
-
cx = outer_w / 2;
85
-
cy = wall_t + spk_grille_cy;
86
-
p = spk_mount_pattern / 2;
76
+
// Detent recesses on each inner wall — small horizontal pockets where
77
+
// the bottom-plate snap tab's bumps catch when the cover is fully
78
+
// seated.
79
+
module snap_recesses() {
80
+
cz = snap_recess_cz;
87
81
88
-
for (sx = [-p, p])
89
-
for (sy = [-p, p])
90
-
translate([cx + sx, cy + sy, outer_h - top_t - EPS])
91
-
cylinder(h = top_t + 2 * EPS, d = spk_mount_hole_d);
92
-
}
82
+
// Front wall (interior face at y = wall_t).
83
+
translate([(outer_w - snap_recess_w) / 2,
84
+
wall_t - EPS,
85
+
cz - snap_recess_h / 2])
86
+
cube([snap_recess_w, snap_recess_d + EPS, snap_recess_h]);
93
87
94
-
// 4 corner bosses inside the chassis. Each has a self-tap pilot hole
95
-
// for an M3 screw coming up from the bottom plate; the screw cuts its
96
-
// own threads in the PLA on first assembly.
97
-
module bottom_plate_screw_bosses() {
98
-
inset = bottom_plate_screw_inset;
88
+
// Back wall (interior face at y = outer_d - wall_t).
89
+
translate([(outer_w - snap_recess_w) / 2,
90
+
outer_d - wall_t - snap_recess_d,
91
+
cz - snap_recess_h / 2])
92
+
cube([snap_recess_w, snap_recess_d + EPS, snap_recess_h]);
99
93
100
-
for (cx = [wall_t + inset, outer_w - wall_t - inset])
101
-
for (cy = [wall_t + inset, outer_d - wall_t - inset])
102
-
difference() {
103
-
translate([cx, cy, 0])
104
-
cylinder(h = bottom_plate_boss_h, d = bottom_plate_boss_d);
105
-
translate([cx, cy, -EPS])
106
-
cylinder(h = bottom_plate_boss_h + 2 * EPS, d = bottom_plate_pilot_d);
107
-
}
108
-
}
94
+
// Left wall (interior face at x = wall_t).
95
+
translate([wall_t - EPS,
96
+
(outer_d - snap_recess_w) / 2,
97
+
cz - snap_recess_h / 2])
98
+
cube([snap_recess_d + EPS, snap_recess_w, snap_recess_h]);
109
99
110
-
module bottom_plate_screw_holes() {
111
-
// No-op placeholder kept inside the chassis difference() block
112
-
// for symmetry. Holes are produced by bottom_plate_screw_bosses().
100
+
// Right wall (interior face at x = outer_w - wall_t).
101
+
translate([outer_w - wall_t - snap_recess_d,
102
+
(outer_d - snap_recess_w) / 2,
103
+
cz - snap_recess_h / 2])
104
+
cube([snap_recess_d + EPS, snap_recess_w, snap_recess_h]);
113
105
}
114
106
115
107
chassis();