ESPHome Multi-Sensor Enclosure (ESP32-C3, SHT41, VEML7700, 24GHz mmWave Radar)

A precision, two-piece, 100% support-free snap-fit enclosure engineered for a high-performance ESPHome / Home Assistant multi-sensor.

It houses an ESP32-C3 SuperMini, an SHT41 temperature/humidity sensor, a VEML7700 ambient light (lux) sensor, and a 24GHz FMCW mmWave radar human presence module in a compact, clean desktop or shelf form factor.

Key Engineering Features

• Dual-Bay Convective Thermal Chimney & Thermal Severance The SHT41 is isolated in a dedicated 3-sided bay with a tongue-and-groove ceiling seal. Underneath, a 1.8 mm through-slot physically severs conductive plastic heat transfer from the electronics bay. Dedicated underside intake louvers pull cool floor air across the SHT41 and exhaust out side louvers, completely separate from the ESP32 exhaust plume.

• Optical Aperture with 45° Conical Funnel The roof holds the VEML7700 light sensor flush against a 3.5 mm top aperture featuring an internal 45° conical bevel, maximizing cosine angle light collection.

• Front-Facing RF Radar Bay Grips a standard 24GHz mmWave radar module upright by its bare PCB edges (zero contact with front antenna traces or solder joints) to beam unimpeded through the 2 mm front face.

• Strain-Relieved USB-C Port Rigid front retention lip and internal thrust shoulders absorb 100% of cable insertion and extraction forces so the USB-C port never fatigues solder joints.

• 100% Support-Free Printing & Tactile Snap-Fit 45° self-releasing snap detents lock the base and shell tightly together with an audible click and flush seams without requiring clips or supports.

Hardware & Bill of Materials (BOM)

• ESP32-C3 SuperMini (~18 × 22.5 mm form factor) • SHT41 Mini Temp/Humidity Sensor (Purple PCB, I2C, ~10.5 × 13.1 mm) • VEML7700 Ambient Light Sensor (Blue PCB, I2C, ~16.5 × 16.5 mm) • 24GHz FMCW mmWave Radar (Standard 5-pin vertical module, ~22.2 × 16 mm) • 1x M2.5 or M2.6 × 5 mm self-tapping screw (for SHT41 base standoff) • 2x M2 or M2.3 × 5 mm self-tapping screws (for VEML7700 roof bosses) • 4x 6 mm × 2 mm rubber bumper feet (Optional - recessed pockets on underside)

Print Settings & Instructions

• Supports: NO (100% support-free design) • Shell Orientation: Print inverted (roof flat on build plate) — the STL room_sensor_shell_PRINT_READY_v25.stl is pre-oriented • Base Orientation: Print flat on build plate (feet pockets facing down) • Layer Height: 0.16 mm – 0.20 mm • Perimeters / Walls: 3 walls (at 0.4 mm nozzle) for strong screw threads • Infill: 20% – 30% (Gyroid or Grid) • Material: PLA, PETG, or ABS

Assembly Instructions

1. Base Electronics:

• Slide the front edge of the ESP32-C3 under the front retention lip, then press flat into the pocket.

• Slide the 24GHz radar module vertically into the edge-grip pillars (antenna plane facing front wall).

• Fasten the SHT41 to the base standoff with one M2.5/M2.6 screw. Route wires through the low-level floor slit into the main electronics bay.

1. Roof Sensor:

• Fasten the VEML7700 face-down against the roof using two M2 screws so the sensor die aligns with the top aperture.

1. Closure:

• Align the shell over the base and press down until the 3-point 45° snap beads click into place.