Micropython webserver stops working when add code to read data from dht11

Question

I've downloaded webserver code from https://docs.micropython.org/en/v1.8/esp8266/esp8266/tutorial/network_tcp.html, it worked well. But after adding code reading dht11 values, webserver stops responding. What's wrong with my code?

import machine
import dht
import socket
import network
sta_if = network.WLAN(network.STA_IF)
sta_if.connect(SSID, PASS)

addr = socket.getaddrinfo('0.0.0.0', 80)[0][-1]
d = machine.Pin(5, machine.Pin.IN, machine.Pin.PULL_UP)

def measure():
    d.measure()
    temp = d.temperature()
    hum = d.humidity()
    return temp, hum

s = socket.socket()
s.bind(addr)
s.listen(1)

print('listening on', addr)

while True:
    cl, addr = s.accept()
    print('client connected from', addr)
    cl_file = cl.makefile('rwb', 0)
    while True:
        line = cl_file.readline()
        if not line or line == b'\r\n':
            break
    response = measure()
    cl.send(response)
    cl.close()

Answer 1

I see two problems with your code:

First, to read the DHT11 sensor you need to use a DHT object. Try replacing

d = machine.Pin(5, machine.Pin.IN, machine.Pin.PULL_UP) 

with

d = dht.DHT11(machine.Pin(5))

Second, the output of your measure() function is a numeric tuple and you're passing that directly to cl.send(), but that method needs a bytes object. You need to encode the two values into a string then convert that into bytes first. Instead of

cl.send(response)

you probably want something like

message = 'Temperature {} Humidity {}'.format(response[0], response[1])
cl.send(bytes(message, 'utf-8'))