Atmosphere Demo 1 Documentation (Second Edition)

1. Project Overview

Atmosphere is a smart monitoring and early-warning system for flash floods and debris flows at outdoor streams / drifting sites.

Demo 1 implements: soil moisture, flow, and wind sensing + pump control + web monitoring + early-warning model.

Main controller: Arduino Nano (ATmega328P, new bootloader)

Soil moisture sensor: AO->A2 (analog), DO->D2 (digital / disconnection detect), VCC->5V, GND->GND

Flow sensor YF-S401: Red->5V, Yellow->D8 (signal), Black->GND

Pump: D7 (HIGH = pump on, LOW = pump off)

Wind sensor (3-cup, 0~5V): on another computer's Arduino UNO A0, forwarded to this machine via HTTP

Two files (both included in this folder):

FlowSensor.ino — Arduino firmware: three-channel sensing + pump control, outputs one JSON line per second over serial (9600)

server.py — Python web service (port 8080): serial reading + wind HTTP integration + warning model + web page

Serial command (single byte): send 1 to turn pump on / 0 to turn off.

Wind endpoint: remote computer http://192.168.1.200:8001/wind returns JSON (wind_ms / wind_kmh / temp / hum).

Debris flow (fully implemented):

Danger index D = 0.40·S̄ + 0.30·Q̄ + 0.20·dQ̄ + 0.10·ΔS̄

S̄ normalized soil moisture, Q̄ normalized flow, dQ̄ flow spike, ΔS̄ soil-moisture rise

Gate: soil moisture < 60% (not saturated) is judged safe directly, does not enter D leveling

Special rules: high soil moisture + sustained flow rise -> escalate level

Flash flood (partially implemented):

Manning formula 70% (needs ultrasonic water-level sensor, not yet implemented)

Spike detection 30% (approximated by per-second flow change rate, threshold TBD)

Sliding baseline (climate-adaptive):

A 24-hour sliding window uses P10/P95 percentiles to judge "how far above local normal"; activates after 2 hours of data.

Warning levels (Level 1 = most severe):

🟢 Normal: D < 0.45 (soil moisture < 60% is judged safe directly)

🟡 Level 3 Alert: 0.45 ≤ D < 0.55

🟠 Level 2 Alert: 0.55 ≤ D < 0.75

🔴 Level 1 Alert: D ≥ 0.75

Compile and upload FlowSensor.ino to the Arduino Nano

Run: python3 -u server.py

Pump powered from the Arduino causes unstable supply and repeated USB resets (auto on/off) — needs an independent power supply

Flash-flood Manning 70% missing ultrasonic water-level sensor, pending

Spike detection threshold needs field calibration