Water leak detector with phone alert (Pico W, MicroPython)

# Water leak detector - Raspberry Pi Pico W (MicroPython).
# Water-level sensor strip on the floor under the RO purifier / washing machine / AC drain:
#   + -> GP22 (powered only while reading, so the traces corrode far slower), S -> GP26 (ADC0), - -> GND.
# Buzzer module: I/O -> GP15, VCC -> 3V3, GND -> GND.
# Wet: the buzzer sounds and a high-priority ntfy alert goes to your phone (repeated every 15 min).
from machine import ADC, Pin
import time
import network
import json

WET_ABOVE = 12000          # raw ADC (0-65535); dry strip reads near 0  <- check with your sensor
CHECK_EVERY_S = 2
REPEAT_ALERT_S = 15 * 60

WIFI_SSID = "your-wifi"
WIFI_PASS = "your-password"
NTFY_TOPIC = "your-private-topic"  # https://ntfy.sh/<topic> - pick something unguessable

# The FlashReady flasher saves your settings to /settings.json; they win over the lines above.
try:
    with open("/settings.json") as f:
        _s = json.load(f)
except (OSError, ValueError):
    _s = {}
WIFI_SSID = _s.get("wifi_ssid") or WIFI_SSID
WIFI_PASS = _s.get("wifi_pass") or WIFI_PASS
NTFY_TOPIC = _s.get("ntfy_topic") or NTFY_TOPIC
ALERTS = WIFI_SSID != "your-wifi" and NTFY_TOPIC != "your-private-topic"
if not ALERTS:
    print("Phone alerts off - no Wi-Fi name or ntfy topic set. Flash from flashready.in or type them into main.py.")

power = Pin(22, Pin.OUT, value=0)
sensor = ADC(26)
buzzer = Pin(15, Pin.OUT, value=0)
led = Pin("LED", Pin.OUT)
wlan = network.WLAN(network.STA_IF)


def wifi_up():
    if not ALERTS:
        return False
    if not wlan.isconnected():
        wlan.active(True)
        wlan.connect(WIFI_SSID, WIFI_PASS)
        for _ in range(20):
            if wlan.isconnected():
                break
            time.sleep(0.5)
    return wlan.isconnected()


def notify(message, priority="default"):
    print(message)
    if not wifi_up():
        return
    try:
        import requests
    except ImportError:
        import urequests as requests
    try:
        requests.post("https://ntfy.sh/" + NTFY_TOPIC, data=message,
                      headers={"Title": "Water leak", "Priority": priority, "Tags": "droplet"}).close()
    except OSError as e:
        print("ntfy failed:", e)


def read_wet():
    power.on()
    time.sleep_ms(10)  # let the strip settle
    raw = sum(sensor.read_u16() for _ in range(4)) // 4
    power.off()
    return raw


wet = False
wet_count = 0
last_alert = 0
notify("Leak detector started", "low")

while True:
    raw = read_wet()
    # Two wet readings in a row before alarming (a single splash or noise is ignored).
    wet_count = wet_count + 1 if raw > WET_ABOVE else 0
    now_wet = wet_count >= 2
    if now_wet and not wet:
        wet = True
        last_alert = time.time()
        notify("WATER LEAK under the RO / machine! (sensor {})".format(raw), "high")
    elif now_wet and time.time() - last_alert > REPEAT_ALERT_S:
        last_alert = time.time()
        notify("Still wet - water leak not fixed yet", "high")
    elif not now_wet and wet and raw < WET_ABOVE // 2:
        wet = False
        notify("Dry again", "low")
    print("raw={} wet={}".format(raw, int(wet)))
    led.value(1 if wet else 0)
    if wet:
        # Pulsed alarm for the 2 s between readings: 0.25 s on, 0.25 s off.
        for _ in range(CHECK_EVERY_S * 2):
            buzzer.on()
            time.sleep(0.25)
            buzzer.off()
            time.sleep(0.25)
    else:
        time.sleep(CHECK_EVERY_S)

# Water leak detector - Raspberry Pi Pico W (MicroPython).
# Water-level sensor strip on the floor under the RO purifier / washing machine / AC drain:
#   + -> GP22 (powered only while reading, so the traces corrode far slower), S -> GP26 (ADC0), - -> GND.
# Buzzer module: I/O -> GP15, VCC -> 3V3, GND -> GND.
# Wet: the buzzer sounds and a high-priority ntfy alert goes to your phone (repeated every 15 min).
from machine import ADC, Pin
import time
import network
import json

WET_ABOVE = 12000          # raw ADC (0-65535); dry strip reads near 0  <- check with your sensor
CHECK_EVERY_S = 2
REPEAT_ALERT_S = 15 * 60

WIFI_SSID = "your-wifi"
WIFI_PASS = "your-password"
NTFY_TOPIC = "your-private-topic"  # https://ntfy.sh/<topic> - pick something unguessable

# The FlashReady flasher saves your settings to /settings.json; they win over the lines above.
try:
    with open("/settings.json") as f:
        _s = json.load(f)
except (OSError, ValueError):
    _s = {}
WIFI_SSID = _s.get("wifi_ssid") or WIFI_SSID
WIFI_PASS = _s.get("wifi_pass") or WIFI_PASS
NTFY_TOPIC = _s.get("ntfy_topic") or NTFY_TOPIC
ALERTS = WIFI_SSID != "your-wifi" and NTFY_TOPIC != "your-private-topic"
if not ALERTS:
    print("Phone alerts off - no Wi-Fi name or ntfy topic set. Flash from flashready.in or type them into main.py.")

power = Pin(22, Pin.OUT, value=0)
sensor = ADC(26)
buzzer = Pin(15, Pin.OUT, value=0)
led = Pin("LED", Pin.OUT)
wlan = network.WLAN(network.STA_IF)


def wifi_up():
    if not ALERTS:
        return False
    if not wlan.isconnected():
        wlan.active(True)
        wlan.connect(WIFI_SSID, WIFI_PASS)
        for _ in range(20):
            if wlan.isconnected():
                break
            time.sleep(0.5)
    return wlan.isconnected()


def notify(message, priority="default"):
    print(message)
    if not wifi_up():
        return
    try:
        import requests
    except ImportError:
        import urequests as requests
    try:
        requests.post("https://ntfy.sh/" + NTFY_TOPIC, data=message,
                      headers={"Title": "Water leak", "Priority": priority, "Tags": "droplet"}).close()
    except OSError as e:
        print("ntfy failed:", e)


def read_wet():
    power.on()
    time.sleep_ms(10)  # let the strip settle
    raw = sum(sensor.read_u16() for _ in range(4)) // 4
    power.off()
    return raw


wet = False
wet_count = 0
last_alert = 0
notify("Leak detector started", "low")

while True:
    raw = read_wet()
    # Two wet readings in a row before alarming (a single splash or noise is ignored).
    wet_count = wet_count + 1 if raw > WET_ABOVE else 0
    now_wet = wet_count >= 2
    if now_wet and not wet:
        wet = True
        last_alert = time.time()
        notify("WATER LEAK under the RO / machine! (sensor {})".format(raw), "high")
    elif now_wet and time.time() - last_alert > REPEAT_ALERT_S:
        last_alert = time.time()
        notify("Still wet - water leak not fixed yet", "high")
    elif not now_wet and wet and raw < WET_ABOVE // 2:
        wet = False
        notify("Dry again", "low")
    print("raw={} wet={}".format(raw, int(wet)))
    led.value(1 if wet else 0)
    if wet:
        # Pulsed alarm for the 2 s between readings: 0.25 s on, 0.25 s off.
        for _ in range(CHECK_EVERY_S * 2):
            buzzer.on()
            time.sleep(0.25)
            buzzer.off()
            time.sleep(0.25)
    else:
        time.sleep(CHECK_EVERY_S)