DHT11 - 積分和小數之差

我在我的arduino uno中使用DHT11傳感器。傳感器發送的數據格式如下： 8位積分相對溼度數據+ 8位十進制相對溼度數據+ 8位積分T數據+ 8位十進制數據+ 8位校驗和。DHT11 - 積分和小數之差

我使用的代碼是：

//KY015 DHT11 Temperature and humidity sensor 
    int DHpin = 8; 
    byte dat [5]; 
    byte read_data() { 
    byte data; 
    for (int i = 0; i < 8; i ++) { 
if (digitalRead (DHpin) == LOW) { 
    while (digitalRead (DHpin) == LOW); // wait for 50us 
    delayMicroseconds (30); // determine the duration of the high level to determine the data is '0 'or '1' 
    if (digitalRead (DHpin) == HIGH) 
    data |= (1 << (7-i)); // high front and low in the post 
    while (digitalRead (DHpin) == HIGH); // data '1 ', wait for the next one receiver 
} 
    } 
    return data; 
    } 

    void start_test() { 
    digitalWrite (DHpin, LOW); // bus down, send start signal 
    delay (30); // delay greater than 18ms, so DHT11 start signal can be detected 

    digitalWrite (DHpin, HIGH); 
    delayMicroseconds (40); // Wait for DHT11 response 

    pinMode (DHpin, INPUT); 
    while (digitalRead (DHpin) == HIGH); 
    delayMicroseconds (80); // DHT11 response, pulled the bus 80us 
    if (digitalRead (DHpin) == LOW); 
    delayMicroseconds (80); // DHT11 80us after the bus pulled to start sending data 

    for (int i = 0; i < 4; i ++) // receive temperature and humidity data, the parity bit is not considered 
dat[i] = read_data(); 

    pinMode (DHpin, OUTPUT); 
    digitalWrite (DHpin, HIGH); // send data once after releasing the bus, wait for the host to open the next Start signal 
    } 

    void setup() { 
    Serial.begin (9600); 
    pinMode (DHpin, OUTPUT); 
    } 

    void loop() { 
    start_test(); 
    Serial.print ("Current humdity ="); 
    Serial.print (dat [0], DEC); // display the humidity-bit integer; 
    Serial.print ('.'); 
    Serial.print (dat [1], DEC); // display the humidity decimal places; 
    Serial.println ('%'); 
    Serial.print ("Current temperature ="); 
    Serial.print (dat [2], DEC); // display the temperature of integer bits; 
    Serial.print ('.'); 
    Serial.print (dat [3], DEC); // display the temperature of decimal places; 
    Serial.println ('C'); 
    delay (700); 
    }

此代碼可能不會是我的最後一個，但我試圖得到一個關於正在發生的事情與傳感器的數據把握。我不明白爲什麼integear數據和小數數據都打印爲DEC也不明白爲什麼有一個「。」那裏。此代碼取自傳感器的維基頁面。我也一直在溼度和溫度的衰變數據部分獲得0。

來源

2016-04-16 Maor

的數據轉換是這樣的對於溼度，

Humidity Value = ((float)((integral RH data << 8) + 8bit decimal RH data)/(float)10.0)

溫度，

Temperature Value = ((float)((8bit integral T data << 8) + 8bit decimal T data)/(float)10.0)

例如：

8bit integral T data = 0x01 and 8bit decimal T data = 0x32 

The real measured temperature value = ((0x01 << 8) + 0x32) /10 
            = (256 + 50)/10 = 30.6 degree c

對溼度也同樣的方式，其將被表示在%。請注意，這是我爲DHT22做的，其步長（分辨率爲0.1度）爲DHT11，看起來像是1度。

參考代碼

Serial.print ("Current humdity ="); 
Serial.print (dat [0], DEC); // display the humidity-bit integer; 
Serial.print ('.'); 
Serial.print (dat [1], DEC); // display the humidity decimal places; 
Serial.println ('%'); 
Serial.print ("Current temperature ="); 
Serial.print (dat [2], DEC); // display the temperature of integer bits; 
Serial.print ('.'); 
Serial.print (dat [3], DEC); // display the temperature of decimal places; 
Serial.println ('C');

我覺得作爲轉換缺少它不會顯示正確的值。

來源

2016-05-08 16:25:24 Sreekanth

DHT11 - 積分和小數之差

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