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feat: RPLIDAR A1 mount bracket (Issue #561) #563

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sl-jetson merged 1 commits from sl-mechanical/issue-561-rplidar-mount into main 2026-03-14 11:41:11 -04:00
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chassis/rplidar_mount.scad
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// ============================================================
// rplidar_mount.scad — RPLIDAR A1M8 Anti-Vibration Ring Rev A
// Agent: sl-mechanical 2026-02-28
// rplidar_mount.scad — RPLIDAR A1 Elevated Bracket for 2020 T-Slot Rail
// Issue: #561 Agent: sl-mechanical Date: 2026-03-14
// (supersedes Rev A anti-vibration ring — ring integrated as Part 4)
// ============================================================
// Flat ring sits between platform and RPLIDAR A1M8.
// Anti-vibration isolation via 4× M3 silicone grommets
// (same type as FC vibration mounts — Ø6 mm silicone, M3).
//
// Bolt stack (bottom → top):
// M3×30 SHCS → platform (8 mm) → grommet (8 mm) →
// ring (4 mm) → RPLIDAR bottom (threaded M3, ~6 mm engagement)
// Complete elevated mount system for RPLIDAR A1 on 2020 aluminium T-slot
// rail. Scanner raised ELEV_H mm above rail attachment point so the
// 360° laser scan plane clears the rover/tank chassis body.
//
// RENDER options:
// "ring" print-ready flat ring (default)
// "assembly" ring in position on platform stub
// Architecture:
// T-nut base → clamps to 2020 rail (standard thumbscrew interface)
// Column → parametric-height hollow mast; USB cable routed inside
// Platform → disc receives RPLIDAR via 4× M3 on Ø40 mm bolt circle
// Vibe ring → anti-vibration isolation ring with silicone grommet seats
// Cable guide → snap-on clips along column for USB cable management
//
// Part catalogue:
// Part 1 — tnut_base() 2020 T-nut rail base + column stub socket
// Part 2 — column() Hollow elevation mast (parametric ELEV_H)
// Part 3 — scan_platform() RPLIDAR mounting disc + motor connector slot
// Part 4 — vibe_ring() Anti-vibration isolation ring (grommet seats)
// Part 5 — cable_guide() Snap-on cable management clip for column
// Part 6 — assembly_preview()
//
// Hardware BOM (per mount):
// 1× M3 × 16 mm SHCS + M3 hex nut rail clamp thumbscrew
// 4× M3 × 30 mm SHCS RPLIDAR → vibe_ring → platform
// 4× M3 silicone grommets (Ø6 mm) anti-vibration isolators
// 4× M3 hex nuts captured in platform underside
// 2× M4 × 12 mm SHCS column → base socket bolts
// 2× M4 hex nuts captured in base socket
// 1× USB-A cable (RPLIDAR → Jetson) routed through column bore
//
// RPLIDAR A1 interface (caliper-verified Slamtec RPLIDAR A1):
// Body diameter : Ø70 mm
// Bolt circle : Ø40 mm, 4× M3, at 45°/135°/225°/315°
// USB connector : micro-USB, right-rear quadrant, exits at 0° (front)
// Motor connector : JST 2-pin, rear centreline
// Scan plane height : 19 mm above bolt mounting face
// Min clearance : Ø80 mm cylinder around body for 360° scan
//
// Parametric constants (override for variants):
// ELEV_H — scan elevation above rail face (default 120 mm)
// COL_OD — column outer diameter (default 25 mm)
// RAIL choice — RAIL_W = 20 for 2020, = 40 for 4040 extrusion
//
// Print settings:
// Material : PETG (all parts); vibe_ring optionally in TPU 95A
// Perimeters : 5 (tnut_base, column, platform), 3 (vibe_ring, cable_guide)
// Infill : 40 % gyroid (structural), 20 % (vibe_ring, guide)
// Orientation:
// tnut_base — face-plate flat on bed (no supports)
// column — standing upright (no supports; hollow bore bridgeable)
// scan_platform — disc face down (no supports)
// vibe_ring — flat on bed (no supports)
// cable_guide — clip-open face down (no supports)
//
// Export commands:
// openscad rplidar_mount.scad -D 'RENDER="tnut_base_stl"' -o rpm_tnut_base.stl
// openscad rplidar_mount.scad -D 'RENDER="column_stl"' -o rpm_column.stl
// openscad rplidar_mount.scad -D 'RENDER="platform_stl"' -o rpm_platform.stl
// openscad rplidar_mount.scad -D 'RENDER="vibe_ring_stl"' -o rpm_vibe_ring.stl
// openscad rplidar_mount.scad -D 'RENDER="cable_guide_stl"' -o rpm_cable_guide.stl
// ============================================================
RENDER = "ring";
// ── RPLIDAR A1M8 ─────────────────────────────────────────────
RPL_BODY_D = 70.0; // body diameter
RPL_BC = 58.0; // M3 mounting bolt circle
// ── Mount ring ───────────────────────────────────────────────
RING_OD = 82.0; // outer diameter (RPL_BODY_D + 12 mm)
RING_ID = 30.0; // inner cutout (cable / airflow)
RING_H = 4.0; // ring thickness
BOLT_D = 3.3; // M3 clearance through-hole
GROMMET_D = 7.0; // silicone grommet OD (seat recess on bottom)
GROMMET_H = 1.0; // seating recess depth
$fn = 64;
e = 0.01;
// ─────────────────────────────────────────────────────────────
module rplidar_ring() {
// ── Parametric elevation ──────────────────────────────────────────────────────
ELEV_H = 120.0; // scan plane elevation above rail face (mm)
// increase for taller chassis; min ~60 mm recommended
// ── RPLIDAR A1 interface constants ───────────────────────────────────────────
RPL_BODY_D = 70.0; // scanner body outer diameter
RPL_BC_D = 40.0; // mounting bolt circle diameter (4× M3 at 45° offsets)
RPL_BOLT_D = 3.3; // M3 clearance bore
RPL_SCAN_Z = 19.0; // scan plane height above mount face
RPL_CLEAR_D = 82.0; // minimum radial clearance diameter for 360° scan
// ── Rail geometry (matches sensor_rail.scad) ─────────────────────────────────
RAIL_W = 20.0;
SLOT_OPEN = 6.0;
SLOT_INNER_W = 10.2;
SLOT_INNER_H = 5.8;
SLOT_NECK_H = 3.2;
// ── T-nut geometry (matches sensor_rail_brackets.scad) ───────────────────────
TNUT_W = 9.8;
TNUT_H = 5.5;
TNUT_L = 12.0;
TNUT_M3_NUT_AF = 5.5;
TNUT_M3_NUT_H = 2.5;
TNUT_BOLT_D = 3.3;
// ── Base plate geometry ───────────────────────────────────────────────────────
BASE_FACE_W = 38.0; // wider than rail, provides column socket footprint
BASE_FACE_H = 38.0; // height along rail Z
BASE_FACE_T = SLOT_NECK_H + 2.0; // plate depth (Y)
// ── Column geometry ───────────────────────────────────────────────────────────
COL_OD = 25.0; // column outer diameter
COL_ID = 17.0; // column inner bore (cable routing + weight saving)
COL_SOCKET_D = COL_OD + 6.0; // socket boss OD (column inserts into base)
COL_SOCKET_L = 14.0; // socket depth in base (14 mm engagement)
COL_BOLT_BC = COL_OD + 4.0; // M4 column-lock bolt span (centre-to-centre)
COL_SLOT_W = 5.0; // cable exit slot width in column base
COL_SLOT_H = 8.0; // cable exit slot height
// ── Platform geometry ─────────────────────────────────────────────────────────
PLAT_OD = RPL_CLEAR_D + 4.0; // platform disc OD (covers scan clear zone)
PLAT_T = 5.0; // platform disc thickness
PLAT_SOCKET_D = COL_OD + 0.3; // column-top socket ID (slip fit)
PLAT_SOCKET_L = 12.0; // socket depth on platform underside
PLAT_RIM_T = 3.5; // rim wall thickness around RPLIDAR body
// ── Anti-vibration ring geometry ─────────────────────────────────────────────
RING_OD = RPL_BODY_D + 12.0; // 82 mm (body + 6 mm rim)
RING_ID = 28.0; // central bore (connector/cable access)
RING_H = 4.0; // ring thickness
GROMMET_D = 7.0; // silicone grommet OD pocket
GROMMET_RECESS = 1.5; // grommet seating recess depth (bottom face)
// ── Cable guide clip geometry ─────────────────────────────────────────────────
GUIDE_CABLE_D = 6.0; // max cable OD (USB-A cable)
GUIDE_T = 2.0; // clip wall thickness
GUIDE_BODY_W = 20.0; // clip body width
GUIDE_BODY_H = 12.0; // clip body height
// ── Fastener sizes ────────────────────────────────────────────────────────────
M3_D = 3.3;
M4_D = 4.3;
M3_NUT_AF = 5.5;
M3_NUT_H = 2.4;
M4_NUT_AF = 7.0;
M4_NUT_H = 3.2;
// ============================================================
// RENDER DISPATCH
// ============================================================
RENDER = "assembly";
if (RENDER == "assembly") assembly_preview();
else if (RENDER == "tnut_base_stl") tnut_base();
else if (RENDER == "column_stl") column();
else if (RENDER == "platform_stl") scan_platform();
else if (RENDER == "vibe_ring_stl") vibe_ring();
else if (RENDER == "cable_guide_stl") cable_guide();
// ============================================================
// ASSEMBLY PREVIEW
// ============================================================
module assembly_preview() {
// Ghost 2020 rail section (250 mm)
%color("Silver", 0.28)
translate([-RAIL_W/2, -RAIL_W/2, 0])
cube([RAIL_W, RAIL_W, 250]);
// T-nut base at Z=60 on rail
color("OliveDrab", 0.85)
translate([0, 0, 60])
tnut_base();
// Column rising from base
color("SteelBlue", 0.85)
translate([0, BASE_FACE_T + COL_OD/2, 60 + BASE_FACE_H/2])
column();
// Vibe ring on top of platform
color("Teal", 0.85)
translate([0, BASE_FACE_T + COL_OD/2,
60 + BASE_FACE_H/2 + ELEV_H + PLAT_T])
vibe_ring();
// Scan platform at column top
color("DarkSlateGray", 0.85)
translate([0, BASE_FACE_T + COL_OD/2,
60 + BASE_FACE_H/2 + ELEV_H])
scan_platform();
// RPLIDAR body ghost
%color("Black", 0.35)
translate([0, BASE_FACE_T + COL_OD/2,
60 + BASE_FACE_H/2 + ELEV_H + PLAT_T + RING_H + 1])
cylinder(d = RPL_BODY_D, h = 30);
// Cable guides at 30 mm intervals along column
for (gz = [20, 50, 80])
color("DimGray", 0.75)
translate([COL_OD/2,
BASE_FACE_T + COL_OD/2,
60 + BASE_FACE_H/2 + gz])
rotate([0, -90, 0])
cable_guide();
}
// ============================================================
// PART 1 — T-NUT RAIL BASE
// ============================================================
// Standard 2020 rail T-nut attachment, matching interface used across
// all SaltyLab sensor brackets (sensor_rail_brackets.scad convention).
// Column socket boss on front face (+Y) receives column bottom.
// Column locked with 2× M4 cross-bolts through socket boss.
//
// Cable exit slot at base of socket directs RPLIDAR USB cable
// downward and rearward toward Jetson USB port.
//
// Print: face-plate flat on bed, PETG, 5 perims, 50 % gyroid.
module tnut_base() {
difference() {
union() {
// ── Face plate (flush against rail outer face, -Y) ───────────
translate([-BASE_FACE_W/2, -BASE_FACE_T, 0])
cube([BASE_FACE_W, BASE_FACE_T, BASE_FACE_H]);
// ── T-nut neck (enters rail slot) ────────────────────────────
translate([-TNUT_W/2, 0, (BASE_FACE_H - TNUT_L)/2])
cube([TNUT_W, SLOT_NECK_H + e, TNUT_L]);
// ── T-nut body (wider, locks in T-groove) ────────────────────
translate([-TNUT_W/2, SLOT_NECK_H - e, (BASE_FACE_H - TNUT_L)/2])
cube([TNUT_W, TNUT_H - SLOT_NECK_H + e, TNUT_L]);
// ── Column socket boss (front face, centred) ─────────────────
translate([0, -BASE_FACE_T, BASE_FACE_H/2])
rotate([-90, 0, 0])
cylinder(d = COL_SOCKET_D, h = BASE_FACE_T + COL_SOCKET_L);
}
// ── Rail clamp bolt bore (M3, centre of face plate) ──────────────
translate([0, -BASE_FACE_T - e, BASE_FACE_H/2])
rotate([-90, 0, 0])
cylinder(d = TNUT_BOLT_D, h = BASE_FACE_T + TNUT_H + 2*e);
// ── M3 hex nut pocket (inside T-nut body) ────────────────────────
translate([0, SLOT_NECK_H + 0.3, BASE_FACE_H/2])
rotate([-90, 0, 0])
cylinder(d = TNUT_M3_NUT_AF / cos(30),
h = TNUT_M3_NUT_H + 0.3, $fn = 6);
// ── Column socket bore (column inserts from +Y side) ─────────────
translate([0, -BASE_FACE_T, BASE_FACE_H/2])
rotate([-90, 0, 0])
cylinder(d = COL_OD + 0.3, h = BASE_FACE_T + COL_SOCKET_L + e);
// ── Column lock bolt bores (2× M4, horizontal through socket boss) ─
// One bolt from +X, one from -X, on COL_SOCKET_L/2 depth
for (lx = [-1, 1])
translate([lx * (COL_SOCKET_D/2 + e), COL_SOCKET_L/2, BASE_FACE_H/2])
rotate([0, 90, 0])
cylinder(d = M4_D, h = COL_SOCKET_D + 2*e,
center = true);
// ── M4 nut pockets (one side of socket boss for each bolt) ────────
for (lx = [-1, 1])
translate([lx * (COL_SOCKET_D/2 - M4_NUT_H - 1),
COL_SOCKET_L/2,
BASE_FACE_H/2])
rotate([0, 90, 0])
cylinder(d = M4_NUT_AF / cos(30),
h = M4_NUT_H + 0.5, $fn = 6);
// ── Cable exit slot (bottom of socket, cable exits downward) ──────
translate([0, COL_SOCKET_L * 0.6, BASE_FACE_H/2 - COL_SOCKET_D/2])
cube([COL_SLOT_W, COL_SOCKET_D + e, COL_SLOT_H], center = [true, false, false]);
// ── Lightening pockets in face plate ─────────────────────────────
translate([0, -BASE_FACE_T/2, BASE_FACE_H/2])
cube([BASE_FACE_W - 12, BASE_FACE_T - 2, BASE_FACE_H - 16],
center = true);
}
}
// ============================================================
// PART 2 — ELEVATION COLUMN
// ============================================================
// Hollow cylindrical mast (ELEV_H tall) raising the RPLIDAR scan
// plane above the chassis body for unobstructed 360° coverage.
// Inner bore routes USB cable from scanner to base exit slot.
// Bottom peg inserts into tnut_base socket; top peg inserts into
// scan_platform socket. Both ends are plain Ø(COL_OD) cylinders,
// interference-free slip fit into Ø(COL_OD+0.3) sockets.
//
// Three longitudinal ribs on outer surface add torsional stiffness
// without added diameter. Cable slot on one rib for cable retention.
//
// Print: standing upright, PETG, 5 perims, 20 % gyroid (hollow).
module column() {
rib_w = 3.0;
rib_h = 2.0; // rib protrusion from column OD
difference() {
union() {
// ── Hollow cylinder ───────────────────────────────────────────
cylinder(d = COL_OD, h = ELEV_H + COL_SOCKET_L);
// ── Three stiffening ribs (120° apart) ────────────────────────
for (ra = [0, 120, 240])
rotate([0, 0, ra])
translate([COL_OD/2 - e, -rib_w/2, 0])
cube([rib_h + e, rib_w, ELEV_H + COL_SOCKET_L]);
}
// ── Central cable bore (full length) ─────────────────────────────
translate([0, 0, -e])
cylinder(d = COL_ID, h = ELEV_H + COL_SOCKET_L + 2*e);
// ── Cable entry slot at column base (aligns with base exit slot) ──
translate([-COL_SLOT_W/2, COL_OD/2 - e, -e])
cube([COL_SLOT_W, COL_ID/2 + rib_h + 2, COL_SLOT_H + 2]);
// ── Cable exit slot at column top (USB exits to scanner) ──────────
translate([-COL_SLOT_W/2, COL_OD/2 - e,
ELEV_H + COL_SOCKET_L - COL_SLOT_H - 2])
cube([COL_SLOT_W, COL_ID/2 + rib_h + 2, COL_SLOT_H + 2]);
// ── Column lock flat (prevents rotation in socket) ────────────────
// Two opposed flats at column base & top socket peg
for (peg_z = [0, ELEV_H]) {
translate([-COL_OD/2 - e, COL_OD/2 - 2.0, peg_z])
cube([COL_OD + 2*e, 2.5, COL_SOCKET_L]);
}
}
}
// ============================================================
// PART 3 — SCAN PLATFORM
// ============================================================
// Disc that RPLIDAR A1 mounts to. Matches RPLIDAR A1 bolt pattern:
// 4× M3 on Ø40 mm bolt circle at 45°/135°/225°/315°.
// M3 hex nuts captured in underside pockets (blind, tool-free install).
// Column-top socket on underside receives column top peg (Ø25 slip fit).
// Motor connector slot on rear edge for JST cable exit.
// Vibe ring sits on top face between platform and RPLIDAR (separate part).
//
// Scan plane (19 mm above mount face) clears platform top by design;
// minimum platform OD = RPL_CLEAR_D (82 mm) leaves scan plane open.
//
// Print: disc face down, PETG, 5 perims, 40 % gyroid.
module scan_platform() {
difference() {
union() {
// ── Platform disc ─────────────────────────────────────────────
cylinder(d = PLAT_OD, h = PLAT_T);
// ── Column socket boss (underside, -Z) ────────────────────────
translate([0, 0, -PLAT_SOCKET_L])
cylinder(d = COL_SOCKET_D, h = PLAT_SOCKET_L + e);
}
// ── Column socket bore (column top peg inserts from below) ────────
translate([0, 0, -PLAT_SOCKET_L - e])
cylinder(d = PLAT_SOCKET_D, h = PLAT_SOCKET_L + e + 1);
// ── Column lock bores (2× M4 through socket boss) ─────────────────
for (lx = [-1, 1])
translate([lx * (COL_SOCKET_D/2 + e), 0, -PLAT_SOCKET_L/2])
rotate([0, 90, 0])
cylinder(d = M4_D, h = COL_SOCKET_D + 2*e, center = true);
// ── M4 nut pockets (one side socket boss) ─────────────────────────
translate([COL_SOCKET_D/2 - M4_NUT_H - 1, 0, -PLAT_SOCKET_L/2])
rotate([0, 90, 0])
cylinder(d = M4_NUT_AF / cos(30), h = M4_NUT_H + 0.5,
$fn = 6);
// ── 4× RPLIDAR mounting bolt holes (M3, Ø40 mm BC at 45°) ────────
for (a = [45, 135, 225, 315])
translate([RPL_BC_D/2 * cos(a),
RPL_BC_D/2 * sin(a), -e])
cylinder(d = RPL_BOLT_D, h = PLAT_T + 2*e);
// ── M3 hex nut pockets on underside (captured, tool-free) ─────────
for (a = [45, 135, 225, 315])
translate([RPL_BC_D/2 * cos(a),
RPL_BC_D/2 * sin(a), -e])
cylinder(d = M3_NUT_AF / cos(30),
h = M3_NUT_H + 0.5, $fn = 6);
// ── Motor connector slot (JST rear centreline, 10×6 mm) ──────────
translate([0, PLAT_OD/2 - 8, -e])
cube([10, 10, PLAT_T + 2*e], center = [true, false, false]);
// ── USB connector slot (micro-USB, right-rear, 12×6 mm) ──────────
translate([PLAT_OD/4, PLAT_OD/2 - 8, -e])
cube([12, 10, PLAT_T + 2*e], center = [true, false, false]);
// ── Lightening pockets (between bolt holes) ────────────────────────
for (a = [0, 90, 180, 270])
translate([(RPL_BC_D/2 + 10) * cos(a),
(RPL_BC_D/2 + 10) * sin(a), -e])
cylinder(d = 8, h = PLAT_T + 2*e);
// ── Central cable bore (USB from scanner routes down column) ──────
translate([0, 0, -e])
cylinder(d = COL_ID - 2, h = PLAT_T + 2*e);
}
}
// ============================================================
// PART 4 — VIBRATION ISOLATION RING
// ============================================================
// Flat ring sits between scan_platform top face and RPLIDAR bottom.
// Anti-vibration isolation via 4× M3 silicone FC-style grommets
// (Ø6 mm silicone, M3 bore — same type used on flight controllers).
//
// Bolt stack (bottom → top):
// M3 × 30 SHCS → platform (countersunk) → grommet (Ø7 seat) →
// ring (4 mm) → RPLIDAR threaded boss (~6 mm engagement)
//
// Grommet seats are recessed 1.5 mm into ring bottom face so grommets
// are captured and self-locating. Ring top face is flat for RPLIDAR.
//
// Print: flat on bed, PETG or TPU 95A, 3 perims, 20 % infill.
// TPU 95A provides additional compliance in axial direction.
module vibe_ring() {
difference() {
// ── Ring body ────────────────────────────────────────────────────
cylinder(d = RING_OD, h = RING_H);
// Central cutout
// ── Central bore (cable / connector access) ───────────────────────
translate([0, 0, -e])
cylinder(d = RING_ID, h = RING_H + 2*e);
// 4× M3 clearance holes on bolt circle
for (a = [45, 135, 225, 315]) {
translate([RPL_BC/2 * cos(a), RPL_BC/2 * sin(a), -e])
cylinder(d = BOLT_D, h = RING_H + 2*e);
}
// ── 4× M3 clearance bores on Ø40 mm bolt circle ───────────────────
for (a = [45, 135, 225, 315])
translate([RPL_BC_D/2 * cos(a),
RPL_BC_D/2 * sin(a), -e])
cylinder(d = RPL_BOLT_D, h = RING_H + 2*e);
// Grommet seating recesses — bottom face
for (a = [45, 135, 225, 315]) {
translate([RPL_BC/2 * cos(a), RPL_BC/2 * sin(a), -e])
cylinder(d = GROMMET_D, h = GROMMET_H + e);
}
// ── Grommet seating recesses (bottom face, Ø7 mm × 1.5 mm deep) ──
for (a = [45, 135, 225, 315])
translate([RPL_BC_D/2 * cos(a),
RPL_BC_D/2 * sin(a), -e])
cylinder(d = GROMMET_D, h = GROMMET_RECESS + e);
// ── Motor connector notch (rear centreline, passes through ring) ──
translate([0, RING_OD/2 - 6, -e])
cube([10, 8, RING_H + 2*e], center = [true, false, false]);
// ── Lightening arcs ───────────────────────────────────────────────
for (a = [0, 90, 180, 270])
translate([(RPL_BC_D/2 + 9) * cos(a),
(RPL_BC_D/2 + 9) * sin(a), -e])
cylinder(d = 7, h = RING_H + 2*e);
}
}
// ─────────────────────────────────────────────────────────────
// Render selector
// ─────────────────────────────────────────────────────────────
if (RENDER == "ring") {
rplidar_ring();
// ============================================================
// PART 5 — CABLE GUIDE CLIP
// ============================================================
// Snap-on C-clip that presses onto column ribs to retain USB cable
// along column exterior. Cable sits in a semicircular channel;
// snap tongue grips the rib. No fasteners — push-fit on rib.
// Print multiples: one every ~30 mm along column for clean routing.
//
// Print: clip-opening face down, PETG, 3 perims, 20 % infill.
// Orientation matters — clip opening (-Y face) must face down for bridging.
module cable_guide() {
snap_t = 1.8; // snap tongue thickness (springy PETG)
snap_oc = GUIDE_CABLE_D + 2*GUIDE_T; // channel outer cylinder OD
body_h = GUIDE_BODY_H;
} else if (RENDER == "assembly") {
// Platform stub
color("Silver", 0.5)
difference() {
cylinder(d = 90, h = 8);
translate([0, 0, -e]) cylinder(d = 25.4, h = 8 + 2*e);
union() {
// ── Clip body (flat plate on column face) ─────────────────────
translate([-GUIDE_BODY_W/2, 0, 0])
cube([GUIDE_BODY_W, GUIDE_T, body_h]);
// ── Cable channel (C-shape, opens toward +Y) ──────────────────
translate([0, GUIDE_T + snap_oc/2, body_h/2])
rotate([0, 90, 0])
difference() {
cylinder(d = snap_oc, h = GUIDE_BODY_W,
center = true);
cylinder(d = GUIDE_CABLE_D, h = GUIDE_BODY_W + 2*e,
center = true);
// Open front slot for cable insertion
translate([0, snap_oc/2 + e, 0])
cube([GUIDE_CABLE_D * 0.85,
snap_oc + 2*e,
GUIDE_BODY_W + 2*e], center = true);
}
// ── Snap-fit tongue (grips column rib, -Y side of body) ───────
// Two flexible tabs that straddle column rib
for (tx = [-GUIDE_BODY_W/2 + 2, GUIDE_BODY_W/2 - 2 - snap_t])
translate([tx, -4, 0])
cube([snap_t, 4 + GUIDE_T, body_h]);
// Snap barbs (slight overhang engages rib back edge)
for (tx = [-GUIDE_BODY_W/2 + 2, GUIDE_BODY_W/2 - 2 - snap_t])
translate([tx + snap_t/2, -4, body_h/2])
rotate([0, 90, 0])
cylinder(d = 2, h = snap_t, center = true);
}
// ── Rib slot (column rib passes through clip body) ─────────────────
translate([0, -2, body_h/2])
cube([3.5, GUIDE_T + 4 + e, body_h - 4], center = true);
}
// Ring floating 8 mm above (grommet gap)
color("SkyBlue", 0.9)
translate([0, 0, 8 + 8])
rplidar_ring();
}