Real‑Time Temperature & Humidity Monitoring via Web on Raspberry Pi 4

In this project, a Raspberry Pi 4 hosts a lightweight Bottle web server that reads data from an Adafruit DHT11 temperature‑humidity sensor and returns the values in real time. An RGB LED mounted on the board lights up in a distinct color for each request, giving instant visual feedback that the server is functioning.

How it works

• Navigate to https://pi‑address:6789/ to trigger the root route. The red LED turns on while the page loads.
• After the page loads, you can press one of the three buttons:
  • Blue – displays the current humidity and turns the LED blue.
  • Green – displays the current temperature and turns the LED green.
  • Red (Stop) – clears the display, resets the LED to red, and stops continuous updates.
• Each button sends a GET request every second until the stop button is pressed or the browser window is closed.
• Stopping the server with Ctrl+C turns off all LEDs and cleans up the GPIO pins.

Hardware schematic

Server code

from bottle import route, run, template, request
import RPi.GPIO as GPIO
import Adafruit_DHT

# Configure GPIO mode
GPIO.setmode(GPIO.BCM)

# Sensor configuration – DHT11 connected to GPIO 25
sensor_type = Adafruit_DHT.DHT11
sensor_pin = 25
GPIO.setup(sensor_pin, GPIO.IN)

# RGB LED pins
GPIO.setup(14, GPIO.OUT)  # Red
GPIO.setup(15, GPIO.OUT)  # Green
GPIO.setup(18, GPIO.OUT)  # Blue

# Helper to turn all LEDs off
def set_leds_off():
    GPIO.output(14, GPIO.LOW)
    GPIO.output(15, GPIO.LOW)
    GPIO.output(18, GPIO.LOW)

# Routes
@route('/')
def index():
    set_leds_off()
    GPIO.output(14, GPIO.HIGH)
    return template('index.html')

@route('/humidity')
def humidity():
    set_leds_off()
    GPIO.output(18, GPIO.HIGH)
    humidity, temperature = Adafruit_DHT.read(sensor_type, sensor_pin)
    return {'humidity': humidity}

@route('/temperature')
def temperature_route():
    set_leds_off()
    GPIO.output(15, GPIO.HIGH)
    humidity, temperature = Adafruit_DHT.read(sensor_type, sensor_pin)
    return {'temperature': temperature}

@route('/stop')
def stop():
    set_leds_off()
    GPIO.output(14, GPIO.HIGH)
    return {'stop': 'No further updates.'}

# Start the Bottle server
run(host='0.0.0.0', port='6789')
# Clean up on exit
set_leds_off()
GPIO.cleanup()

Source: Get Humidity/Temperature from Web