// ============================================================ // 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) // ============================================================ // // 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. // // 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 // ============================================================ $fn = 64; e = 0.01; // ── 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 bore (cable / connector access) ─────────────────────── translate([0, 0, -e]) cylinder(d = RING_ID, 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, 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); } } // ============================================================ // 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; difference() { 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); } }