A nightstand noise generator based on M5Stack Atom Echo and integrating with Home Assistant
first-pass 3D-printable enclosure in OpenSCAD
The assembled nightstand unit gets a printable shell. `make enclosure`
renders three STLs to `enclosure/build/`: the chassis (open-bottom shell
with integrated top), a separate bottom plate that screws on with four
M3 self-tap screws, and a translucent snooze cap. The chassis houses
the Atom Echo press-fit onto a daughterboard via M5's 5+4 "Atom Stack"
header pattern, a MAX98357A I2S amp, and the Adafruit 1314 speaker.
Snooze cap on the front-top half presses the Atom's button via a
captive plunger; speaker fires up through a perforated grille on the
rear-top half; USB-C exits a cutout in the back wall.
Layout decisions worth flagging for future archaeology:
* Speaker fires up — less directional, more room-filling for a
nightstand. Snooze cap on the near (front) half of the top, grille on
the far (rear) half.
* No internal divider between the snooze and speaker zones — single
shared chamber so the USB-C cable can route from the front-mounted
Atom straight to the rear cutout. White noise through a 3" driver
doesn't need a sealed speaker chamber.
* Press-fit on the 5+4 side headers as the only Atom mount — no screws
on the Atom itself. M5's mechanical drawing shows two M2 mounting
holes on the bottom face, but they aren't externally accessible on
the actual unit (covered by the label sticker).
* Bottom plate screws into corner bosses with M3 self-tap into PLA;
four register tabs on the plate keep it laterally aligned during
assembly before the screws snug.
* 1.5 mm fillet on visible top + side edges; cap top has a 1.5 mm
spherical dome for tactile cue in the dark.
* Daughterboard is hand-soldered protoboard, not a custom-fab PCB.
Standoffs at the four corners of a 38 × 38 footprint for now; will
re-tune once a real piece of perfboard is on the bench.
The reference docs needed several corrections that fell out of measuring
the actual hardware (photos of the bottom, back, and top-right faces
added under `reference/atom-echo/`):
* Bottom face has the 5+4 press-fit headers + a male HY2.0-4P GROVE in
the middle.
* USB-C is on the back face, not the top.
* The onboard NS4168 speaker grille shares the top face with the
button, not the front.
* Planned MAX98357A wiring: I2S DIN moves from G21 (which isn't exposed
on the Atom's external pins) to G25.
* Stale PAM8302 references in the Adafruit 1314 doc updated to
MAX98357A — that path was the rejected analog-amp architecture.
References:
* https://docs.m5stack.com/en/atom/atomecho
* https://www.adafruit.com/product/3006 (MAX98357A breakout)
* https://www.adafruit.com/product/1314 (3" 4Ω speaker)
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
+618
-19
+14
-4
Makefile
+14
-4
Makefile
···
6
6
7
7
MAKEFLAGS += --no-print-directory
8
8
9
-
.PHONY: all firmware firmware-check firmware-flash firmware-flash-monitor firmware-monitor firmware-ota-publish firmware-clean clean help
9
+
.PHONY: all firmware firmware-check firmware-flash firmware-flash-monitor firmware-monitor firmware-ota-publish firmware-clean enclosure enclosure-preview enclosure-clean clean help
10
10
11
11
all: firmware
12
12
···
31
31
firmware-clean:
32
32
$(MAKE) -C firmware clean
33
33
34
-
clean: firmware-clean
34
+
enclosure:
35
+
$(MAKE) -C enclosure all
36
+
37
+
enclosure-preview:
38
+
$(MAKE) -C enclosure preview
39
+
40
+
enclosure-clean:
41
+
$(MAKE) -C enclosure clean
42
+
43
+
clean: firmware-clean enclosure-clean
35
44
36
45
help:
37
46
@echo "sound-machine targets:"
···
43
52
@echo " firmware-monitor serial monitor only"
44
53
@echo " firmware-ota-publish save .bin to OTA_LOCAL_DIR + publish latest_version"
45
54
@echo " firmware-clean cargo clean"
55
+
@echo " enclosure render printable STLs from OpenSCAD into enclosure/build/"
56
+
@echo " enclosure-preview open the enclosure assembly view in OpenSCAD"
57
+
@echo " enclosure-clean remove enclosure/build/"
46
58
@echo " clean clean everything"
47
-
@echo ""
48
-
@echo "Future: 3D model rendering, etc., will live as sibling targets."
+40
enclosure/Makefile
+40
enclosure/Makefile
···
1
+
# Enclosure build — render OpenSCAD parts to printable STLs.
2
+
#
3
+
# Run from the project root via `make enclosure`, or directly here.
4
+
# Renders into build/ (gitignored).
5
+
6
+
OPENSCAD ?= openscad-nightly
7
+
BUILD = build
8
+
PARTS_DIR = parts
9
+
LIB_DIR = lib
10
+
11
+
PARTS = chassis snooze-cap bottom-plate
12
+
STLS = $(PARTS:%=$(BUILD)/%.stl)
13
+
14
+
LIB_FILES = $(wildcard $(LIB_DIR)/*.scad)
15
+
16
+
.PHONY: all preview clean help
17
+
18
+
all: $(STLS)
19
+
20
+
$(BUILD)/%.stl: $(PARTS_DIR)/%.scad $(LIB_FILES) | $(BUILD)
21
+
$(OPENSCAD) -o $@ $<
22
+
23
+
$(BUILD):
24
+
mkdir -p $(BUILD)
25
+
26
+
# Open the assembly view in OpenSCAD for visual inspection.
27
+
preview:
28
+
$(OPENSCAD) enclosure.scad &
29
+
30
+
clean:
31
+
rm -rf $(BUILD)
32
+
33
+
help:
34
+
@echo "enclosure targets:"
35
+
@echo " all (default) render all parts to build/*.stl"
36
+
@echo " preview open enclosure.scad in OpenSCAD for visual review"
37
+
@echo " clean remove build/"
38
+
@echo ""
39
+
@echo " Override OPENSCAD=... if you have a different binary"
40
+
@echo " (default: openscad-nightly)."
+44
enclosure/enclosure.scad
+44
enclosure/enclosure.scad
···
1
+
// Top-level assembly view. Shows all printed parts in their final
2
+
// positions for visual sanity-checking. Open this file in OpenSCAD's
3
+
// preview to inspect the design; do NOT export this as STL — render
4
+
// each individual part file (parts/*.scad) for printable STLs.
5
+
6
+
include <lib/params.scad>
7
+
8
+
$fa = 2;
9
+
$fs = 0.4;
10
+
11
+
// Suppress the trailing chassis(); / snooze_cap(); / bottom_plate();
12
+
// calls in each part file by using `use <>` instead of `include <>`.
13
+
use <parts/chassis.scad>
14
+
use <parts/snooze-cap.scad>
15
+
use <parts/bottom-plate.scad>
16
+
17
+
// Printed shell.
18
+
chassis();
19
+
20
+
// Bottom plate, attached from below.
21
+
bottom_plate();
22
+
23
+
// Snooze cap at rest position (flange touching the underside of the top
24
+
// panel). The cap origin sits with its flange's bottom-front-left at
25
+
// z = outer_h - top_t - snooze_cap_flange_h, x/y centered on the well.
26
+
flange_w_local = snooze_well_w + 2 * snooze_cap_flange_overhang;
27
+
flange_d_local = snooze_well_d + 2 * snooze_cap_flange_overhang;
28
+
translate([(outer_w - flange_w_local) / 2,
29
+
wall_t + snooze_well_cy - flange_d_local / 2,
30
+
outer_h - top_t - snooze_cap_flange_h - (inner_h - (atom_z_bottom + atom_body_h))])
31
+
color("white", 0.6) snooze_cap();
32
+
33
+
// Reference geometry — a translucent box where the Atom Echo lives,
34
+
// for visual verification of clearances. Comment out for a clean view.
35
+
%translate([(outer_w - atom_w) / 2,
36
+
wall_t + snooze_well_cy - atom_d / 2,
37
+
atom_z_bottom])
38
+
cube([atom_w, atom_d, atom_body_h]);
39
+
40
+
// Reference geometry — speaker frame footprint hanging from the top panel.
41
+
%translate([(outer_w - spk_frame) / 2,
42
+
wall_t + spk_grille_cy - spk_frame / 2,
43
+
outer_h - top_t - spk_total_d])
44
+
cube([spk_frame, spk_frame, spk_total_d]);
+177
enclosure/lib/params.scad
+177
enclosure/lib/params.scad
···
1
+
// Sound machine enclosure — shared dimensions.
2
+
// Units: mm. Edit here; everything else derives.
3
+
4
+
// ============================================================
5
+
// Atom Echo (M5Stack C008-C)
6
+
// See: reference/atom-echo/dimensions.md
7
+
// ============================================================
8
+
9
+
atom_w = 24;
10
+
atom_d = 24;
11
+
atom_body_h = 16.8;
12
+
atom_corner_r = 3;
13
+
14
+
// USB-C cutout in the Atom's own back face (vertically centered on body).
15
+
atom_usb_w_native = 11.6;
16
+
atom_usb_h_native = 7;
17
+
18
+
// Bottom-face male HY2.0-4P GROVE connector.
19
+
// Sticks down from the body; sits between the press-fit headers.
20
+
grove_body_w = 8;
21
+
grove_body_d = 4.5;
22
+
grove_body_h = 2.5;
23
+
24
+
// 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
+
header_pitch = 2.54;
27
+
header_left_pin_count = 5;
28
+
header_right_pin_count = 4;
29
+
header_edge_offset = 2.0; // body-edge to pin-row centerline (estimate)
30
+
31
+
// ============================================================
32
+
// MAX98357A I2S amp breakout (Adafruit 3006 / generic clone)
33
+
// See: reference/signal-chain.md
34
+
// ============================================================
35
+
36
+
max_w = 21;
37
+
max_d = 16;
38
+
max_pcb_t = 1.6;
39
+
40
+
// ============================================================
41
+
// Speaker — Adafruit 1314 (3" full-range, 4Ω 3W)
42
+
// See: reference/speakers/adafruit-1314.md
43
+
// ============================================================
44
+
45
+
spk_frame = 77.8; // square frame outer
46
+
spk_total_d = 25.49; // total depth incl. magnet
47
+
spk_mount_pattern = 60; // square M3 hole pattern (centers)
48
+
spk_mount_hole_d = 3.4; // M3 clearance
49
+
spk_cone_cutout = 67; // baffle opening; estimate, measure & update
50
+
spk_magnet_clearance = 30; // air below baffle for magnet + breathing
51
+
52
+
// ============================================================
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.
56
+
// ============================================================
57
+
58
+
dboard_t = 1.6;
59
+
dboard_w = atom_w + 14;
60
+
dboard_d = atom_d + 14;
61
+
dboard_pin_h = 6; // male pin height above the daughterboard
62
+
dboard_standoff_h = 6; // air below the daughterboard
63
+
64
+
// ============================================================
65
+
// Snooze cap + well
66
+
// ============================================================
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
+
snooze_cap_w = 70;
75
+
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
80
+
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
+
snooze_cap_flange_overhang = 3;
84
+
snooze_cap_flange_h = 2;
85
+
86
+
// Well opening in the top panel — derived from the cap.
87
+
snooze_well_w = snooze_cap_w + 2 * snooze_cap_clearance;
88
+
snooze_well_d = snooze_cap_d + 2 * snooze_cap_clearance;
89
+
90
+
// ============================================================
91
+
// Speaker grille (in the rear portion of the top panel)
92
+
// ============================================================
93
+
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.
98
+
grille_diameter = spk_cone_cutout;
99
+
100
+
// ============================================================
101
+
// Enclosure — overall printed shell
102
+
// ============================================================
103
+
104
+
wall_t = 3;
105
+
top_t = 4; // a touch thicker for rigidity around the speaker mount
106
+
bottom_t = 3;
107
+
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;
112
+
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):
125
+
// front_margin | snooze well | zone_gap | speaker grille | back_margin
126
+
front_margin = 8;
127
+
zone_gap = 6;
128
+
back_margin = 6;
129
+
130
+
// Internal volume.
131
+
inner_w = max(dboard_w + 8, spk_frame + 6); // whichever is wider
132
+
inner_d = front_margin + snooze_well_d + zone_gap + spk_frame + back_margin;
133
+
inner_h = max(spk_magnet_clearance + 4,
134
+
dboard_standoff_h + dboard_t + dboard_pin_h + atom_body_h + 3);
135
+
136
+
// Outer envelope.
137
+
outer_w = inner_w + 2 * wall_t;
138
+
outer_d = inner_d + 2 * wall_t;
139
+
outer_h = inner_h + top_t; // bottom is a separate plate; chassis is open-bottom
140
+
141
+
// ============================================================
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.
146
+
// ============================================================
147
+
148
+
usb_hole_w = 14;
149
+
usb_hole_h = 9;
150
+
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;
156
+
157
+
// ============================================================
158
+
// Bottom plate — separate part, screws onto the chassis from below.
159
+
// ============================================================
160
+
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
167
+
168
+
// ============================================================
169
+
// Component placement (X centered; Y measured from the front wall inside)
170
+
// ============================================================
171
+
172
+
// Snooze well center, in chassis-internal coordinates (origin at front-left
173
+
// inside corner of the chamber).
174
+
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;
+49
enclosure/lib/util.scad
+49
enclosure/lib/util.scad
···
1
+
// Shared modules / helpers for the enclosure parts.
2
+
3
+
// A rectangular prism with the four vertical edges filleted by `r`.
4
+
// Top and bottom are sharp; the part still sits flat on the print bed.
5
+
// Bounding box is identical to a plain cube of the same size — corners
6
+
// round inward.
7
+
module rounded_prism(size, r) {
8
+
linear_extrude(height = size[2])
9
+
offset(r = r)
10
+
offset(r = -r)
11
+
square([size[0], size[1]]);
12
+
}
13
+
14
+
// A rectangular prism with rounded vertical edges AND a filleted top —
15
+
// the "softened brick" look. Bottom edges stay sharp so the part can sit
16
+
// flat on the build plate (chassis prints open-bottom-down). Built as
17
+
// the convex hull of cylinder feet at the bottom and a sphere at each
18
+
// top corner, so the top edge is a true fillet.
19
+
module rounded_box_top(size, r) {
20
+
hull() {
21
+
for (x = [r, size[0] - r])
22
+
for (y = [r, size[1] - r]) {
23
+
translate([x, y, 0]) cylinder(h = 0.01, r = r);
24
+
translate([x, y, size[2] - r]) sphere(r);
25
+
}
26
+
}
27
+
}
28
+
29
+
// A rectangular prism with rounded vertical edges and a gentle spherical
30
+
// dome on top. `dome_h` is the rise of the center above the corners, and
31
+
// the dome surface is a spherical section sized so it lands flat at the
32
+
// bounding-box diagonal corners. Bottom stays sharp.
33
+
module domed_box_top(size, r, dome_h) {
34
+
// Spherical cap geometry: dome reaches z = size[2] at the diagonal
35
+
// corners and z = size[2] + dome_h at the center.
36
+
diag_half = sqrt(size[0] * size[0] + size[1] * size[1]) / 2;
37
+
dome_r = (diag_half * diag_half + dome_h * dome_h) / (2 * dome_h);
38
+
39
+
intersection() {
40
+
// Tall prism — slightly taller than the dome peak, gets carved by
41
+
// the sphere underside.
42
+
rounded_prism([size[0], size[1], size[2] + dome_h + 0.5], r);
43
+
44
+
// Big sphere whose upper surface is the dome. Local $fa keeps the
45
+
// tessellation reasonable on a very large radius.
46
+
translate([size[0] / 2, size[1] / 2, size[2] + dome_h - dome_r])
47
+
sphere(dome_r, $fa = 4);
48
+
}
49
+
}
+90
enclosure/parts/bottom-plate.scad
+90
enclosure/parts/bottom-plate.scad
···
1
+
// Bottom plate — closes the open-bottom chassis from below and carries
2
+
// the standoffs that hold the daughterboard.
3
+
//
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.
8
+
9
+
include <../lib/params.scad>
10
+
include <../lib/util.scad>
11
+
12
+
$fa = 2;
13
+
$fs = 0.4;
14
+
15
+
EPS = 0.05;
16
+
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.
27
+
dboard_cx = outer_w / 2;
28
+
dboard_cy = wall_t + snooze_well_cy;
29
+
30
+
module bottom_plate() {
31
+
difference() {
32
+
// Plate body — rounded vertical corners to match the chassis,
33
+
// sharp top and bottom edges (sits flat on the print bed).
34
+
translate([0, 0, -bottom_plate_t])
35
+
rounded_prism([outer_w, outer_d, bottom_plate_t], chassis_round_r);
36
+
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);
45
+
}
46
+
47
+
// 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
+
daughterboard_standoffs();
51
+
52
+
// Register tabs — locate the plate laterally inside the chassis
53
+
// cavity during assembly.
54
+
register_tabs();
55
+
}
56
+
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]);
64
+
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]);
69
+
}
70
+
71
+
module daughterboard_standoffs() {
72
+
standoff_d = 5;
73
+
standoff_id = 1.6; // pilot for self-tapping M2
74
+
inset = 3; // distance from daughterboard edge to standoff center
75
+
76
+
// Standoff top sits at z = dboard_standoff_h (so the daughterboard
77
+
// bottom face rests there).
78
+
for (sx = [dboard_cx - dboard_w / 2 + inset,
79
+
dboard_cx + dboard_w / 2 - inset])
80
+
for (sy = [dboard_cy - dboard_d / 2 + inset,
81
+
dboard_cy + dboard_d / 2 - inset])
82
+
difference() {
83
+
translate([sx, sy, 0])
84
+
cylinder(h = dboard_standoff_h, d = standoff_d);
85
+
translate([sx, sy, -EPS])
86
+
cylinder(h = dboard_standoff_h + 2 * EPS, d = standoff_id);
87
+
}
88
+
}
89
+
90
+
bottom_plate();
+115
enclosure/parts/chassis.scad
+115
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.
4
+
//
5
+
// Coordinate system: origin at the bottom-front-left outer corner.
6
+
// +X = right, +Y = back, +Z = up.
7
+
8
+
include <../lib/params.scad>
9
+
include <../lib/util.scad>
10
+
11
+
$fa = 2;
12
+
$fs = 0.4;
13
+
14
+
EPS = 0.05;
15
+
16
+
module chassis() {
17
+
difference() {
18
+
// Outer envelope — rounded vertical edges + filleted top, sharp
19
+
// bottom so the part sits flat on the build plate.
20
+
rounded_box_top([outer_w, outer_d, outer_h], chassis_round_r);
21
+
22
+
// Inner cavity — open-bottom, so subtract a cube that extends
23
+
// through z=0 and stops at the underside of the top panel.
24
+
translate([wall_t, wall_t, -EPS])
25
+
cube([inner_w, inner_d, inner_h + EPS]);
26
+
27
+
// Snooze well — rounded-corner through-hole in the top panel.
28
+
translate([(outer_w - snooze_well_w) / 2,
29
+
wall_t + snooze_well_cy - snooze_well_d / 2,
30
+
outer_h - top_t - EPS])
31
+
rounded_prism([snooze_well_w, snooze_well_d, top_t + 2 * EPS],
32
+
snooze_well_corner_r);
33
+
34
+
// Speaker grille — a circular field of small holes in the rear
35
+
// portion of the top panel, constrained to the cone diameter.
36
+
speaker_grille();
37
+
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,
44
+
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]);
47
+
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();
52
+
}
53
+
54
+
// Bottom-plate screw bosses, 4 corners inside the chassis.
55
+
bottom_plate_screw_bosses();
56
+
}
57
+
58
+
module speaker_grille() {
59
+
cx = outer_w / 2;
60
+
cy = wall_t + spk_grille_cy;
61
+
r = grille_diameter / 2;
62
+
63
+
// Hexagonal-ish grid clipped to a circle.
64
+
intersection() {
65
+
translate([cx - r, cy - r, outer_h - top_t - EPS])
66
+
cube([2 * r, 2 * r, top_t + 2 * EPS]);
67
+
68
+
union() {
69
+
for (xi = [-r : grille_pitch : r])
70
+
for (yi = [-r : grille_pitch : r]) {
71
+
// Stagger every other row by half-pitch for a nicer pattern.
72
+
xoff = (round(yi / grille_pitch) % 2 == 0) ? 0 : grille_pitch / 2;
73
+
px = cx + xi + xoff;
74
+
py = cy + yi;
75
+
if ((px - cx) * (px - cx) + (py - cy) * (py - cy) <= r * r)
76
+
translate([px, py, outer_h - top_t - EPS])
77
+
cylinder(h = top_t + 2 * EPS, d = grille_hole_d);
78
+
}
79
+
}
80
+
}
81
+
}
82
+
83
+
module speaker_mount_holes() {
84
+
cx = outer_w / 2;
85
+
cy = wall_t + spk_grille_cy;
86
+
p = spk_mount_pattern / 2;
87
+
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
+
}
93
+
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;
99
+
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
+
}
109
+
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().
113
+
}
114
+
115
+
chassis();
+72
enclosure/parts/snooze-cap.scad
+72
enclosure/parts/snooze-cap.scad
···
1
+
// Snooze cap — translucent press button. Drops into the well in the top
2
+
// panel from below; the flange catches on the underside of the top panel
3
+
// as the up-stop. The Atom Echo's tactile dome under the plunger acts as
4
+
// the return spring.
5
+
//
6
+
// Print in translucent or white PLA so the SK6812 LED diffuses through.
7
+
// Print upside-down (cap top on the build plate) for the cleanest first
8
+
// layer on the visible surface — no supports needed.
9
+
//
10
+
// Coordinate system: origin at the bottom-front-left of the flange.
11
+
// The cap is rendered "right side up" — the flange is at z=0, the
12
+
// visible top is at z=cap_total_h.
13
+
14
+
include <../lib/params.scad>
15
+
include <../lib/util.scad>
16
+
17
+
$fa = 2;
18
+
$fs = 0.4;
19
+
20
+
EPS = 0.05;
21
+
22
+
// Distance the plunger has to descend below the flange to reach the Atom
23
+
// button. Derived from the chamber height and the Atom-on-daughterboard
24
+
// stack — when the flange top touches the underside of the top panel,
25
+
// the plunger bottom should just kiss the Atom button.
26
+
atom_button_top_z = atom_z_bottom + atom_body_h;
27
+
plunger_h = inner_h - atom_button_top_z;
28
+
29
+
// Z layout of the cap, bottom-up:
30
+
z_plunger_bot = 0;
31
+
z_plunger_top = plunger_h;
32
+
z_flange_bot = z_plunger_top;
33
+
z_flange_top = z_flange_bot + snooze_cap_flange_h;
34
+
z_body_bot = z_flange_top;
35
+
z_body_top = z_body_bot + top_t + snooze_cap_h_above;
36
+
37
+
// Outer flange XY footprint (also the cap origin reference).
38
+
flange_w = snooze_well_w + 2 * snooze_cap_flange_overhang;
39
+
flange_d = snooze_well_d + 2 * snooze_cap_flange_overhang;
40
+
41
+
module snooze_cap() {
42
+
// Plunger — centered over the Atom Echo footprint.
43
+
translate([(flange_w - atom_w) / 2,
44
+
(flange_d - atom_d) / 2,
45
+
z_plunger_bot])
46
+
cube([atom_w, atom_d, plunger_h]);
47
+
48
+
// Flange — wider than the well opening, catches the underside of
49
+
// the top panel.
50
+
translate([0, 0, z_flange_bot])
51
+
cube([flange_w, flange_d, snooze_cap_flange_h]);
52
+
53
+
// Body — split into two stacked sections so we can round only the
54
+
// visible top edges, while still having consistent rounded vertical
55
+
// edges throughout (so the joint at z = top_t is seamless).
56
+
body_x = (flange_w - snooze_cap_w) / 2;
57
+
body_y = (flange_d - snooze_cap_d) / 2;
58
+
59
+
// Lower body — passes through the well, hidden. Rounded vertical
60
+
// edges, flat top/bottom.
61
+
translate([body_x, body_y, z_body_bot])
62
+
rounded_prism([snooze_cap_w, snooze_cap_d, top_t], cap_round_r);
63
+
64
+
// Upper body — visible above the top panel. Rounded vertical edges
65
+
// and a gentle spherical dome on top.
66
+
translate([body_x, body_y, z_body_bot + top_t])
67
+
domed_box_top([snooze_cap_w, snooze_cap_d, snooze_cap_h_above],
68
+
cap_round_r,
69
+
cap_dome_h);
70
+
}
71
+
72
+
snooze_cap();
reference/atom-echo/atom-back.jpg
reference/atom-echo/atom-back.jpg
This is a binary file and will not be displayed.
reference/atom-echo/atom-bottom.jpg
reference/atom-echo/atom-bottom.jpg
This is a binary file and will not be displayed.
reference/atom-echo/atom-top-right.jpg
reference/atom-echo/atom-top-right.jpg
This is a binary file and will not be displayed.
+12
-10
reference/atom-echo/dimensions.md
+12
-10
reference/atom-echo/dimensions.md
···
2
2
3
3
- **Body**: 24 × 24 × 16.8 mm (near-cube)
4
4
- **Corner radius**: R3 (body), R0.5 (USB-C cutout)
5
-
- **USB-C port**: on top face, ~11.6 mm wide
6
-
- **Speaker grille**: front face
7
-
- **Button**: top face (through the RGB LED button cap)
8
-
- **Mounting**: 2 holes on bottom face, 12 mm apart, centered — M2 screws
9
-
- **GROVE connector**: back face (HY2.0-4P)
5
+
- **Top face**: shares the button (curved cap with embedded SK6812 RGB LED) on one side and the onboard NS4168 speaker grille (grid of small holes) on the other. Both occupy the same 24 × 24 mm face.
6
+
- **USB-C port**: back face, ~11.6 mm wide cutout, vertically centered on the 16.8 mm body height. The HY2.0-4P GROVE connector body protrudes downward from the bottom face right at the rear edge, so its opening is also visible from this back angle — leave clearance for it when sizing the rear cutout.
7
+
- **Side faces**: no connectors or features; just regulatory markings (CE / FCC) on the label.
8
+
- **Front face**: small mic port (SPM1423), no other features.
9
+
- **Bottom face**: female pin headers for press-fit "Atom Stack" mounting — 5-pin header on one side, 4-pin header on the other, plus a male HY2.0-4P GROVE connector centered between them. M5's mechanical drawing also shows two M2 screw holes on this face but they are not externally accessible on the actual unit (covered by the label sticker), so press-fit via the headers is the practical mount.
10
10
11
11
## Enclosure implications
12
12
13
13
The Atom Echo itself will be the "compute module" inside a larger nightstand enclosure. Need to account for:
14
14
15
-
- Cable exits: USB-C (power) and GROVE (if we use it) — both on opposite faces
16
-
- Button access: the top-face button is the whole top surface, so the enclosure needs to either expose it or transmit the press mechanically
17
-
- LED visibility: the SK6812 glows through the button — same access concern
18
-
- Mic port: there's a small hole on the body for the mic (visible in dimension drawing); probably won't matter since we're only using it for output, but if we ever want wake-word later we'd need an acoustic path
19
-
- Mounting: two M2 screw posts inside the enclosure, 12 mm apart
15
+
- **Mounting**: a daughterboard sitting below the Atom with male pin headers in a matching 5+4 footprint (and optionally a female HY2.0-4P in the middle) friction-fits the Atom in place. Same daughterboard carries electrical signals to the MAX98357A. Atom Echo lifts straight up for service. This is M5's intended "Atom Stack" pattern.
16
+
- **USB-C cable exit**: rear face of the Atom is flush against the rear wall of the enclosure, with a small rectangular cutout (≥12 × 7 mm to clear the port + plug shell) so any USB-C cable plugs in from outside — no hand reach into the enclosure required.
17
+
- **Button + LED**: top face points up at the underside of the snooze cap. The cap covers the full 24 × 24 mm top face (the silent onboard NS4168 speaker grille shares this face but is unused), transmits press downward onto the Atom's button, and the SK6812 LED shines up through the (translucent) cap.
18
+
- **Mic port**: small hole on the front face; output-only design ignores it. If wake-word ever becomes a goal we'd need an acoustic path through the enclosure.
20
19
21
20
## Sources
22
21
23
22
- [Atom Echo product docs (M5Stack)](https://docs.m5stack.com/en/atom/atomecho) — dimensions section
24
23
- [module-size.jpg](./module-size.jpg) — mechanical drawing, downloaded from M5Stack docs
24
+
- [atom-bottom.jpg](./atom-bottom.jpg) — photo of the actual unit's bottom face, showing the 5+4 press-fit headers and the central HY2.0-4P
25
+
- [atom-back.jpg](./atom-back.jpg) — photo of the back face: USB-C port and the rear-edge view of the GROVE connector
26
+
- [atom-top-right.jpg](./atom-top-right.jpg) — photo of the top + side faces: button outline + onboard speaker grille on top, regulatory label on the side
+2
-3
reference/signal-chain.md
+2
-3
reference/signal-chain.md
···
54
54
| GND | GND | |
55
55
| G26 (GROVE yellow) | BCLK | bit clock |
56
56
| G32 (GROVE white) | LRC | word select (LRCK) |
57
-
| G21 (side header) | DIN | I2S serial data |
57
+
| G25 (side header) | DIN | I2S serial data — only safely-available external GPIO (G19/G22/G23/G33 are reserved for the onboard NS4168, G27 is the RGB LED, G39 is the button) |
58
58
| — | SD | leave floating = mono (L+R summed) |
59
59
| — | GAIN | leave floating = 9 dB default |
60
60
···
104
104
105
105
- G26 (GROVE yellow) → I2S BCLK
106
106
- G32 (GROVE white) → I2S LRC
107
-
- G21 (side header) → I2S DIN
108
-
- G25 (side header) → free spare (future button, rotary encoder, IR, etc.)
107
+
- G25 (side header) → I2S DIN
109
108
110
109
## Parts list for this chain (per unit)
111
110
+2
-2
reference/speakers/adafruit-1314.md
+2
-2
reference/speakers/adafruit-1314.md
···
26
26
27
27
## Why this is fine for our use
28
28
29
-
- **Power match**: 3 W handling vs. PAM8302 delivering ~2.5 W into 4 Ω at 5V. Comfortable headroom; we'll never run the amp at max anyway.
30
-
- **Impedance match**: PAM8302 is rated for 4Ω loads. Exact match.
29
+
- **Power match**: 3 W handling vs. MAX98357A delivering ~3.2 W into 4 Ω at 5V. Essentially matched; white noise never runs near max anyway.
30
+
- **Impedance match**: MAX98357A is rated for 4Ω loads. Exact match.
31
31
- **Size match**: 78 mm baffle + a few mm per side for the enclosure wall gives a face ~90 mm square. Reasonable nightstand footprint.
32
32
- **White noise doesn't care about bass extension**, so a sealed box with any sensible internal volume (~0.3 L+) will sound fine. Fill with polyfill / pillow stuffing to damp standing waves.
33
33