DHT11 Web Server using ESP32 & MicroPython
DHT11 Web Server using ESP32 & MicroPython is a runnable microcontroller simulation example on SensBench — open the wired circuit, inspect the code, and compile real firmware in your browser, no install needed. Last updated Aug 14, 2026.
FREE SIMULATOR EXAMPLE · INTERMEDIATE
DHT11 Web Server using ESP32 & MicroPython
This example serves live DHT11 readings from the ESP32 over HTTP — open the page in any browser and see the current temperature and humidity. The ESP32 as sensor, server and dashboard in one MicroPython script.
| Board | ESP32 DevKit (Xtensa LX6, 240 MHz) |
|---|---|
| Difficulty | intermediate |
| Category | communication |
| Libraries | None — just the Arduino core |
| Runs in | Sensbench browser simulator — free, no account |
The exact circuit you get when you open this example — already wired, ready to run.
The sketch
# main.py
import machine
import network
import time
import socket
import dht
# DHT11 sensor setup
sensor = dht.DHT11(machine.Pin(4)) # GPIO4 connected
# Wi-Fi credentials
SSID = "kritish"
PASSWORD = "@Krrs2069"
# Wi-Fi connection
wifi = network.WLAN(network.STA_IF)
wifi.active(True)
if not wifi.isconnected():
print("Connecting to WiFi...", end="")
wifi.connect(SSID, PASSWORD)
while not wifi.isconnected():
time.sleep(1)
print(".", end="")
print("\nConnected to WiFi:", wifi.ifconfig()[0])
else:
print("Already connected to WiFi:", wifi.ifconfig()[0])
def web_page(temp, hum):
# Corrected HTML with proper humidity unit and a cleaner f-string format.
html = f"""<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>ESP32 DHT11 SERVER</title>
<meta http-equiv="refresh" content="3">
<style>
body {{
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
text-align: center;
background: linear-gradient(to right, #f6ff00, #a600ff);
color: white;
margin: 0;
padding: 0;
}}
h1 {{
margin-top: 20px;
font-size: 2.5em;
text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
}}
.container {{
display: flex;
justify-content: center;
align-items: center;
gap: 20px;
margin-top: 50px;
}}
.card {{
background: rgba(255, 255, 255, 0.15);
padding: 30px;
border-radius: 20px;
box-shadow: 0 8px 16px rgba(0,0,0,0.3);
width: 250px;
transition: transform 0.2s;
}}
.card:hover {{
transform: scale(1.05);
}}
.value {{
font-size: 2em;
margin-top: 10px;
font-weight: bold;
}}
</style>
</head>
<body>
<h1>ESP32 DHT11 WEBSERVER</h1>
<div class="container">
<div class="card">
<h2>🌡 Temperature</h2>
<div class="value">{temp} °C</div>
</div>
<div class="card">
<h2>💧 Humidity</h2>
<div class="value">{hum} %</div>
</div>
</div>
<p style="margin-top:40px;">Auto-refreshing every 3 seconds ⏳</p>
<p class="footer">© 2025 Kritish. Powered by MicroPython.</p>
</body>
</html>"""
return html
# Start web server
addr = socket.getaddrinfo("0.0.0.0", 80)[0][-1]
server = socket.socket()
server.bind(addr)
server.listen(1)
print("Web server running on:", wifi.ifconfig()[0])
while True:
try:
# Read sensor
sensor.measure()
temp = sensor.temperature()
hum = sensor.humidity()
# Handle client
client, addr = server.accept()
print("Client connected from", addr)
request = client.recv(1024)
# Check for valid sensor readings before serving the page
if isinstance(temp, (int, float)) and isinstance(hum, (int, float)):
response = web_page(temp, hum)
else:
# Handle cases where sensor reading fails
response = "<h1>Sensor reading failed. Please try again.</h1>"
client.send("HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n\r\n")
client.sendall(response)
client.close()
except OSError as e:
print("Failed to read sensor or a socket error occurred:", e)
time.sleep(10) # Wait a bit before trying again
except Exception as e:
print("An unexpected error occurred:", e)
time.sleep(10)How it works
The script reads the DHT11 on a GPIO and serves a small web page that displays the temperature and humidity, refreshed on each request. The HTTP handler does the sensor read inline, so every page load shows a fresh measurement.
The DHT11’s one-wire protocol is handled by the MicroPython dht module — the script only calls measure() and reads the values. The 1-second minimum between reads is enforced by the request rate in practice, but the module’s internal timing guards against faster polling.
Before you build it for real
The DHT11’s 1-second minimum interval is a hard limit — poll faster and the readings go stale or the sensor returns errors; the module enforces it, but a busy server can still serve the same reading to ten clients. The sensor wants the pull-up resistor that breakout boards include and bare parts do not. And the web server has no authentication: anyone on the network reads the values — fine for a room thermometer, wrong for anything sensitive.
Get the parts
Related examples
FAQ
Why DHT11 instead of DHT22?
The DHT11 is the cheaper sibling: integer-only readings, ±2 °C accuracy, and a 1-second minimum interval. For a web demo the lower cost and simpler protocol win. The DHT22 examples elsewhere in the collection show the upgrade path when decimal precision matters.
Why serve the readings over HTTP?
A web server is the zero-install dashboard: any browser on the same network opens the page and sees the numbers. No app, no cloud account — the ESP32 is the sensor, the server and the display endpoint in one.