print("Hello, ESP32!")
import time
import dht
import network
from machine import Pin
DHT_PIN = 4
LED_PIN = 2 # status LED - stands in for the "application layer" output
sensor = dht.DHT22(Pin(DHT_PIN))
status_led = Pin(LED_PIN, Pin.OUT)
SSID = "Wokwi-GUEST"
PASSWORD = ""
def connect_wifi():
wlan = network.WLAN(network.STA_IF)
wlan.active(True)
if not wlan.isconnected():
print("[NETWORK LAYER] Connecting to WiFi...")
wlan.connect(SSID, PASSWORD)

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timeout = 10
while not wlan.isconnected() and timeout > 0:
time.sleep(1)
timeout -= 1
if wlan.isconnected():
print("[NETWORK LAYER] Connected. Device IP:", wlan.ifconfig()[0])
else:
print("[NETWORK LAYER] WiFi unavailable - continuing in local-only mode.")
return wlan.isconnected()
wifi_ok = connect_wifi()
print("=====================================================")
print(" IoT ARCHITECTURE DEMO: Perception -> Network -> Application")
print("=====================================================")
while True:
try:
# ---------------- 1) PERCEPTION LAYER ----------------
sensor.measure()
t = sensor.temperature()
h = sensor.humidity()
print("[PERCEPTION LAYER] Raw sensor data -> Temp: {} C, Humidity: {}
%".format(t, h))
# ---------------- 2) NETWORK LAYER ----------------
if wifi_ok:
print("[NETWORK LAYER] Data packaged and ready for transmission to
cloud/server.")
else:
print("[NETWORK LAYER] No connectivity - data stays on the local device
only.")
# ---------------- 3) APPLICATION LAYER ----------------
if t > 30:
status_led.value(1)
print("[APPLICATION LAYER] Decision: Temperature high -> Actuator (LED)
turned ON")

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else:
status_led.value(0)
print("[APPLICATION LAYER] Decision: Temperature normal -> Actuator
(LED) turned OFF")
print("-----------------------------------------------------")
except OSError as e:
print("[PERCEPTION LAYER] Sensor read failed:", e)
time.sleep(3)