Freenove Ultimate Starter Kit - Page 235

235
Chapter 21 Hygrothermograph DHT11
█ www.freenove.com
support@freenove.com █
The following is the program code:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
im port RPi. GPIO as GPIO
im port time
im port Freenove_DHT as DHT
DHTPin = 11 #define the pin of DHT11
def loop():
dht = DHT.DHT(DHTPin) #create a DHT class object
sumCnt = 0 #number of reading times
w hile(True):
sumCnt += 1 #counting number of reading times
chk = dht. readDHT11() #read DHT11 and get a return value. Then determine
whether data read is normal according to the return value.
print ("The sumCnt is : %d, \t chk : %d"%(sumCnt,chk))
if (chk is dht. DHTLIB_OK): #read DHT11 and get a return value. Then
determine whether data read is normal according to the return value.
print("DHT11,OK!")
elif(chk is dht. DHTLIB_ERROR_CHECKSUM): #data check has errors
print("DHTLIB_ERROR_CHECKSUM!!")
elif(chk is dht. DHTLIB_ERROR_TIMEOUT): #reading DHT times out
print("DHTLIB_ERROR_TIMEOUT!")
else: #other errors
print("Other error!")
print("Humidity : %.2f, \t Temperature : %.2f \n"%(dht.humidity,dht.temperature))
time.sleep(2)
if __name__ == '__main__':
p rint ('Program is starting ... ')
try:
loop()