Design
System architecture
How a pressure reading becomes a local alert.
Signal chain
BMP390 sensor
Barometric pressure + temperature at 1 Hz
Calibration
Offset, gain and temperature correction
Filtering
Detrend and band-pass 0.01–0.5 Hz
Feature extraction
Change rate, RMS, FFT band energy
Detection
Multi-criteria scoring with cross-node check
Communication
LoRa to gateway, ESP-NOW to peer
Local alert
Siren + regional-language voice
Hardware bill of materials
MicrocontrollerESP32-WROOM-32
Pressure sensorBosch BMP390
RadioSX1276 LoRa, 865 MHz
AudioDFPlayer Mini + 10 W speaker
Siren12 V piezo via MOSFET
Power18650 pack + 6 V solar panel
StoragemicroSD logger