Files

root 0240020cd2 Initial design: ESP32-S3 presence sensor with camera, mmWave, PIR, temp/humidity, light

- KiCad schematic and PCB layout (45x35mm board)
- Full BOM with JLCPCB part numbers
- ESPHome firmware configuration
- 3D-printable wall-mount enclosure (OpenSCAD + STL)
- Pin mapping and power budget documentation

2026-03-29 12:53:54 -05:00

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ESP32-S3 Presence Sensor

Compact wall-mount presence sensor with camera, mmWave radar, PIR, temperature/humidity, and ambient light sensing. Designed for Home Assistant via ESPHome.

Features

5MP Camera (OV5640, 120° wide-angle) - video stream to HA
24GHz mmWave Radar (LD2410C) - presence detection even when still
PIR Sensor (AM312) - instant motion trigger
Temp/Humidity (SHT41) - ±0.2°C accuracy
Light Sensor (BH1750) - 1-65535 lux
USB-C powered - any 1A+ charger
~45x35mm PCB - wall mountable

How Detection Works

Motion event:
  PIR (AM312) ──→ instant trigger (ms response)
       │
       ▼
  mmWave (LD2410C) ──→ sustained presence tracking
       │                (detects breathing/typing)
       ▼
  Combined "Occupancy" ──→ true if either sensor active
                           30s delay before "unoccupied"

PIR catches fast motion immediately. mmWave confirms someone is still in the room even when sitting perfectly still. The combined sensor gives zero false-offs.

Project Files

File	Description
`presence-sensor.kicad_pro`	KiCad project file
`presence-sensor.kicad_sch`	Schematic
`PIN_MAPPING.md`	GPIO assignments and power budget
`BOM.csv`	Bill of materials with JLCPCB part numbers
`esphome-presence-sensor.yaml`	ESPHome firmware config

Build Instructions

1. Order PCBs

Open project in KiCad 8+
Complete PCB layout (place components, route traces)
Generate Gerbers: File → Plot → Gerber
Upload to JLCPCB
Enable SMD assembly, upload BOM.csv

2. Order Modules (plug-in, not soldered by JLCPCB)

OV5640 camera module (24-pin 0.5mm FPC, wide-angle 120°)
HLK-LD2410C mmWave radar module
AM312 mini PIR sensor

3. Assembly

Solder LD2410C to 1.27mm header
Solder AM312 to 2.54mm header
Connect OV5640 via FPC cable

4. Flash Firmware

# Install ESPHome
pip install esphome

# Create secrets.yaml
cat > secrets.yaml << EOF
wifi_ssid: "your-wifi"
wifi_password: "your-password"
api_key: "generate-a-key"
ota_password: "your-ota-password"
fallback_password: "your-fallback"
EOF

# Flash via USB-C (hold BOOT, press RESET, release BOOT)
esphome run esphome-presence-sensor.yaml

5. Add to Home Assistant

ESPHome auto-discovers the device
Settings → Devices & Services → ESPHome → Configure

Cost Per Board

Item	Cost
PCB fabrication (5pcs)	~$8 total
SMD assembly	~$12/board
Components on PCB	~$5.50/board
OV5640 camera module	~$3.50
LD2410C radar	~$2.50
AM312 PIR	~$0.50
Total per board	~$32

Design Notes

Antenna Clearance

ESP32-S3 antenna extends past board edge
No copper pour under antenna area (top or bottom)
Keep antenna away from LD2410C radar module

Thermal

SHT41 placed on board edge, away from ESP32 heat
-1.5°C offset in ESPHome config (calibrate after testing)
Enclosure should have ventilation slots near SHT41

mmWave Orientation

LD2410C mounted perpendicular to wall for widest room coverage
Detection cone is ~60° in each direction
Optimal height: 1.2-1.5m from floor

Camera

OV5640 connects via 24-pin FPC flex cable
Camera module sits at top of enclosure, angled slightly down
120° wide-angle lens covers most of a room from wall mount

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