saltylab-firmware/chassis/ip54_BOM.md

IP54 Weatherproofing Kit BOM — Issue #144

Agent: sl-mechanical | Date: 2026-03-01

IP54-rated enclosures and sensor housings for all-weather outdoor robot operation.

---

A. Main Electronics Enclosure (ip54_enclosure.scad)

Purchased Hardware

#	Description	Spec	Qty	Source / Notes
E1	PG7 cable gland	IP68, nylon, Ø3–6 mm cable range	4	Lapp Skintop® or equivalent
E2	PG9 cable gland	IP68, nylon, Ø4–8 mm cable range	2	Lapp Skintop® or equivalent
E3	Silicone O-ring cord	Ø2 mm cord, silicone 70 Shore A	~800 mm	Cut to lid perimeter length; butt-join with silicone sealant
E4	40 mm axial fan	12 V DC, sleeve bearing, >10 CFM	1	Sunon MF40201VX or Noctua NF-A4x10
E5	Foam filter pad	40×40×5 mm open-cell PPI 30	2	Cut from foam sheet; replace when dirty
E6	Al heat sink pad — Jetson	60×40×2 mm, adhesive back	1	Bergquist GP3000 or Arctic Thermal Pad
E7	Al heat sink pad — ESC	50×30×2 mm, adhesive back	1	Same source as E6
E8	Thermal interface material	1 mm silicone pad, Rth ≤ 1.0 °C·cm²/W	2	Between board and heat sink pad
E9	Spring washer M10	For quarter-turn latch preload	4	DIN 127, stainless
E10	M3×8 SHCS	Stainless	8	Fan + duct mounting
E11	M3×30 SHCS	Stainless	4	Quarter-turn latch knob bolt
E12	M3×6 BHCS	Stainless	16	PCB standoff mounting (Jetson×4, FC×4, ESC×8)
E13	M3 brass heat-set insert	M3×4 L, Ø5.1 OD	16	Press into standoffs with soldering iron
E14	Silicone adhesive sealant	Clear, weatherproof, Dowsil 732 or equivalent	1 tube	Seal cable gland threads + O-ring cord join

Printed Parts

Part	File	Qty	Print	Mass est.
Enclosure body	ip54_enclosure.scad body_stl	1	PETG, 5 perims, 40% infill, 0.25 mm layer	~320 g
Lid with fan mount	ip54_enclosure.scad lid_stl	1	PETG, 5 perims, 40% infill	~185 g
Fan filter duct	ip54_enclosure.scad fan_duct_stl	1	PETG, 4 perims, 30% infill	~28 g
Quarter-turn latch knob	ip54_enclosure.scad latch_stl	4	PETG, 5 perims, 60% infill	~6 g each

Gasket DXF

File	Description
ip54_gasket.dxf	O-ring groove outline for laser-cut 2 mm silicone sheet (alternative to cord)

---

B. IMX219 Camera Dome (ip54_sensor_housings.scad)

#	Description	Spec	Qty (per camera)	Notes
C1	Clear PC dome cylinder	Ø55×35 mm, 2 mm wall, clear polycarbonate	1	Vac-form custom OR source clear plastic sphere halves; DXF from imx219_dome_2d
C2	Silicone O-ring	Ø55 mm ID, 2 mm cord	1	Seals dome to base ring
C3	Silica gel sachet	1 g, demountable	1	Anti-fog; replace yearly or when saturated
C4	M2×6 SHCS	Stainless	4	PCB to standoffs
C5	M3×10 BHCS	Stainless	4	Base ring to sensor rail bracket
C6	Anti-fog spray	Rain-X interior or similar	—	Apply to dome inner face during assembly

Printed Part	Qty	Print	Mass est.
Dome base ring	4 (1 per camera)	PETG, 5 perims, 60% infill	~22 g
Retainer ring	4	PETG, 4 perims, 40% infill	~8 g

---

C. D435i Sealed Housing (ip54_sensor_housings.scad)

#	Description	Spec	Qty	Notes
D1	IR-transparent PC window	88×22×3 mm, >85% T at 850 nm	1	Evonik PLEXIGLAS IR 8N or Altuglas IR; export profile from d435i_window_2d
D2	Silicone O-ring	2 mm cord, approx 230 mm perimeter	1	Seals window frame to housing front face
D3	Silicone O-ring	2 mm cord, rear cap seal	1
D4	PG7 cable gland	Rear cap	1	For D435i USB-C cable
D5	M2.5×10 SHCS	Window frame screws	4
D6	M3×6 SHCS	Housing-to-bracket top	3
D7	1/4-20 UNC hex nut	Captured in bottom	1	For tripod/bracket mount

Printed Part	Qty	Print	Mass est.
D435i housing body	1	PETG, 5 perims, 40% infill	~65 g
Window retention frame	1	PETG, 5 perims, 60% infill	~18 g
Rear cap	1	PETG, 5 perims, 60% infill	~20 g

---

D. RPLIDAR Spinning Dome (ip54_sensor_housings.scad)

#	Description	Spec	Qty	Notes
R1	Clear PC cylinder	Ø120 mm OD, 1.5–2 mm wall, 95 mm tall	1	Source: plastic cylinder tube or custom vac-form; spec from rplidar_dome_2d
R2	Clear PC disc cap	Ø120 mm, 2 mm, clear PC	1	Seals dome top; laser-cut from rplidar_dome_cap_2d export
R3	Silicone O-ring	Ø120 mm ID, 2 mm cord	1	Seals dome cylinder to base ring
R4	M3×6 captive bolt	For dome retention clips	3	Press-fit into clip
R5	M4×8 BHCS	Deck mounting	4	Base ring to deck plate
R6	M3×8 SHCS	RPLIDAR to base ring	4	Standard RPLIDAR A1M8 M3 bolts

Printed Part	Qty	Print	Mass est.
RPLIDAR dome base ring	1	PETG, 5 perims, 60% infill	~55 g
Dome retention clip	3	PETG, 5 perims, 60% infill	~4 g each

---

Thermal Management Summary

Component	Thermal strategy	Max junction	Enclosure budget
Jetson Orin NX	Al pad → lid → fan forced convection	95 °C Tj	Target ≤ 60 °C case
FC (ESP32 BALANCE)	Passive; FC has own EMI shield	85 °C	<60 °C ambient OK
ESC × 2	Al pad → lid	100 °C Tj	Target ≤ 60 °C
D435i	Passive; housing vent gap on rear cap	45 °C surface	—

Fan spec: 40 mm, 12 V, ≥10 CFM at 0.1" H₂O static pressure. Thermal analysis (simplified): ΔT = Q/(m_dot × Cp) where Q = 15 W (Jetson 10 W + ESC 5 W), airflow = 10 CFM = 4.7 L/s. ΔT_air ≈ 15 / (4.7 × 1.2 × 1005) ≈ 2.7 °C rise over ambient. With conduction resistance (pad + wall): Tcase ≈ Tambient + 12 °C. At 40 °C ambient → 52 °C max. Within 60 °C target. ✓

---

Mass Summary

Assembly	Mass est.
Enclosure (body + lid + duct + latches)	~560 g
4× IMX219 domes	~120 g
D435i housing (body + frame + cap)	~103 g
RPLIDAR dome assembly	~67 g
Hardware + glands	~80 g
Total kit	~930 g

---

IP54 Compliance Checklist

• Box O-ring groove: 2 mm cord, 70% compression → IP54 ✓
• Cable glands: PG7/PG9 IP68 rated — exceeds lid requirement ✓
• Fan inlet: labyrinth duct prevents direct splash to fan bore ✓
• Exhaust: double-baffle labyrinth on lid rear ✓
• Camera domes: O-ring sealed to base ring ✓
• D435i housing: O-ring on window frame + rear cap ✓
• RPLIDAR dome: O-ring at dome-to-base seat ✓
• ⚠ Verify O-ring cord continuity — no gaps at corners after cut-and-join
• ⚠ Test after print — submerge base (static) in 200 mm water for 30 min (IP54 splash test)
• ⚠ D435i IR window — confirm PC sheet IR transmission spec with supplier before ordering

---

Export Commands

# Enclosure
openscad ip54_enclosure.scad -D 'RENDER="body_stl"'     -o ip54_body.stl
openscad ip54_enclosure.scad -D 'RENDER="lid_stl"'      -o ip54_lid.stl
openscad ip54_enclosure.scad -D 'RENDER="fan_duct_stl"' -o ip54_fan_duct.stl
openscad ip54_enclosure.scad -D 'RENDER="latch_stl"'    -o ip54_latch.stl
openscad ip54_enclosure.scad -D 'RENDER="gasket_2d"'    -o ip54_gasket.dxf

# Sensor housings
openscad ip54_sensor_housings.scad -D 'RENDER="imx219_dome_stl"'  -o imx219_dome.stl
openscad ip54_sensor_housings.scad -D 'RENDER="imx219_dome_2d"'   -o imx219_dome_disc.dxf
openscad ip54_sensor_housings.scad -D 'RENDER="d435i_body_stl"'   -o d435i_body.stl
openscad ip54_sensor_housings.scad -D 'RENDER="d435i_window_2d"'  -o d435i_window.dxf
openscad ip54_sensor_housings.scad -D 'RENDER="d435i_frame_stl"'  -o d435i_frame.stl
openscad ip54_sensor_housings.scad -D 'RENDER="rplidar_base_stl"' -o rplidar_dome_base.stl
openscad ip54_sensor_housings.scad -D 'RENDER="rplidar_dome_2d"'  -o rplidar_dome_spec.dxf