arduino dht11库文件arduino-DHT-master下载

单片机源程序如下:

1. #include "DHT.h"
   
2. 
   
3. void DHT::setup(uint8_t pin, DHT_MODEL_t model)
   
4. {
   
5.   DHT::pin = pin;
   
6.   DHT::model = model;
   
7.   DHT::resetTimer(); // Make sure we do read the sensor in the next readSensor()
   
8. 
   
9.   if ( model == AUTO_DETECT) {
   
10.     DHT::model = DHT22;
    
11.     readSensor();
    
12.     if ( error == ERROR_TIMEOUT ) {
    
13.       DHT::model = DHT11;
    
14.       // Warning: in case we auto detect a DHT11, you should wait at least 1000 msec
    
15.       // before your first read request. Otherwise you will get a time out error.
    
16.     }
    
17.   }
    
18. }
    
19. 
    
20. void DHT::resetTimer()
    
21. {
    
22.   DHT::lastReadTime = millis() - 3000;
    
23. }
    
24. 
    
25. float DHT::getHumidity()
    
26. {
    
27.   readSensor();
    
28.   return humidity;
    
29. }
    
30. 
    
31. float DHT::getTemperature()
    
32. {
    
33.   readSensor();
    
34.   return temperature;
    
35. }
    
36. 
    
37. #ifndef OPTIMIZE_SRAM_SIZE
    
38. 
    
39. const char* DHT::getStatusString()
    
40. {
    
41.   switch ( error ) {
    
42.     case DHT::ERROR_TIMEOUT:
    
43.       return "TIMEOUT";
    
44. 
    
45.     case DHT::ERROR_CHECKSUM:
    
46.       return "CHECKSUM";
    
47. 
    
48.     default:
    
49.       return "OK";
    
50.   }
    
51. }
    
52. 
    
53. #else
    
54. 
    
55. // At the expense of 26 bytes of extra PROGMEM, we save 11 bytes of
    
56. // SRAM by using the following method:
    
57. 
    
58. prog_char P_OK[]       PROGMEM = "OK";
    
59. prog_char P_TIMEOUT[]  PROGMEM = "TIMEOUT";
    
60. prog_char P_CHECKSUM[] PROGMEM = "CHECKSUM";
    
61. 
    
62. const char *DHT::getStatusString() {
    
63.   prog_char *c;
    
64.   switch ( error ) {
    
65.     case DHT::ERROR_CHECKSUM:
    
66.       c = P_CHECKSUM; break;
    
67. 
    
68.     case DHT::ERROR_TIMEOUT:
    
69.       c = P_TIMEOUT; break;
    
70. 
    
71.     default:
    
72.       c = P_OK; break;
    
73.   }
    
74. 
    
75.   static char buffer[9];
    
76.   strcpy_P(buffer, c);
    
77. 
    
78.   return buffer;
    
79. }
    
80. 
    
81. #endif
    
82. 
    
83. void DHT::readSensor()
    
84. {
    
85.   // Make sure we don't poll the sensor too often
    
86.   // - Max sample rate DHT11 is 1 Hz   (duty cicle 1000 ms)
    
87.   // - Max sample rate DHT22 is 0.5 Hz (duty cicle 2000 ms)
    
88.   unsigned long startTime = millis();
    
89.   if ( (unsigned long)(startTime - lastReadTime) < (model == DHT11 ? 999L : 1999L) ) {
    
90.     return;
    
91.   }
    
92.   lastReadTime = startTime;
    
93. 
    
94.   temperature = NAN;
    
95.   humidity = NAN;
    
96. 
    
97.   // Request sample
    
98. 
    
99.   digitalWrite(pin, LOW); // Send start signal
    
100.   pinMode(pin, OUTPUT);
     
101.   if ( model == DHT11 ) {
     
102.     delay(18);
     
103.   }
     
104.   else {
     
105.     // This will fail for a DHT11 - that's how we can detect such a device
     
106.     delayMicroseconds(800);
     
107.   }
     
108. 
     
109.   pinMode(pin, INPUT);
     
110.   digitalWrite(pin, HIGH); // Switch bus to receive data
     
111. 
     
112.   // We're going to read 83 edges:
     
113.   // - First a FALLING, RISING, and FALLING edge for the start bit
     
114.   // - Then 40 bits: RISING and then a FALLING edge per bit
     
115.   // To keep our code simple, we accept any HIGH or LOW reading if it's max 85 usecs long
     
116. 
     
117.   uint16_t rawHumidity = 0;
     
118.   uint16_t rawTemperature = 0;
     
119.   uint16_t data = 0;
     
120. 
     
121.   for ( int8_t i = -3 ; i < 2 * 40; i++ ) {
     
122.     byte age;
     
123.     startTime = micros();
     
124. 
     
125.     do {
     
126.       age = (unsigned long)(micros() - startTime);
     
127.       if ( age > 90 ) {
     
128.         error = ERROR_TIMEOUT;
     
129.         return;
     
130.       }
     
131.     }
     
132.     while ( digitalRead(pin) == (i & 1) ? HIGH : LOW );
     
133. 
     
134.     if ( i >= 0 && (i & 1) ) {
     
135.       // Now we are being fed our 40 bits
     
136.       data <<= 1;
     
137. 
     
138.       // A zero max 30 usecs, a one at least 68 usecs.
     
139.       if ( age > 30 ) {
     
140.         data |= 1; // we got a one
     
141.       }
     
142.     }
     
143. 
     
144.     switch ( i ) {
     
145.       case 31:
     
146.         rawHumidity = data;
     
147.         break;
     
148.       case 63:
     
149.         rawTemperature = data;
     
150.         data = 0;
     
151.         break;
     
152.     }
     
153.   }
     
154. 
     
155.   // Verify checksum
     
156. 
     
157.   if ( (byte)(((byte)rawHumidity) + (rawHumidity >> 8) + ((byte)rawTemperature) + (rawTemperature >> 8)) != data ) {
     
158.     error = ERROR_CHECKSUM;
     
159.     return;
     
160.   }
     
161. 
     
162.   // Store readings
     
163. 
     
164.   if ( model == DHT11 ) {
     
165.     humidity = rawHumidity >> 8;
     
166.     temperature = rawTemperature >> 8;
     
167.   }
     
168.   else {
     
169.     humidity = rawHumidity * 0.1;
     
170. 
     
171.     if ( rawTemperature & 0x8000 ) {
     
172.       rawTemperature = -(int16_t)(rawTemperature & 0x7FFF);
     
173.     }
     
174.     temperature = ((int16_t)rawTemperature) * 0.1;
     
175.   }
     
176. 
     
177.   error = ERROR_NONE;
     
178. }
     
179. 
     

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arduino-DHT-master (1).zip (42.91 KB, 下载次数: 163)

2019-4-19 18:03 上传

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这个很有用

谢谢分享，这个有用。