回復  pizg
數位溫濕度感測器
In comparison with the DHT11, the DHT33 has a wider measurement range ...
vegewell 發表於 2014-3-25 02:23

   感謝v大,感謝您花了不少時間找來這些資料.

回復 5# pizg
數位溫濕度感測器
In comparison with the DHT11, the DHT33 has a wider measurement range and higher accuracy and long term stability than the DHT22.
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DHT33(RHT04)(解析度最高)
Power supply: 3.3 to 5.5V DC
Output signal: digital signal via MaxDetect 1-wire bus
Sensor type humidity: Polymer humidity capacitor
Sensor type temperature: DS18B20
Operating range: humidity 0 to 100%RH, temperature -40 to 100°C;
Interchangeability: fully interchangeable
Range of meauring humidity: 0% to 100%RH(0-50° temperature compensation)
Range of meauring temperature: -40 to +100°
Resolution or sensitivity: humidity: 0.1%RH, temperature: 0.1°C
Accuracy of measuring humidity: ±2.0%RH
Accuracy of measuring temperature: ±0.5°C
Repeatability: humidity:+-0.5%RH, temperature:+-0.2°C
Supply Current:
Mesurement: 1 to 1.5 mA
Average: 0.2 to 0.5 mA
Stand by: 40 to 50 uA
----------------------------
DHT11
Ultra low cost
3 to 5V power and I/O
2.5mA max current use during conversion (while requesting data)
Good for 20-80% humidity readings with 5% accuracy
Good for 0-50°C temperature readings ±2°C accuracy
No more than 1 Hz sampling rate (once every second)
Body size 15.5mm x 12mm x 5.5mm
4 pins with 0.1" spacing
----------------------------
DHT22
Low cost
3 to 5V power and I/O
2.5mA max current use during conversion (while requesting data)
Good for 0-100% humidity readings with 2-5% accuracy
Good for -40 to 125°C temperature readings ±0.5°C accuracy
No more than 0.5 Hz sampling rate (once every 2 seconds)
Body size 15.1mm x 25mm x 7.7mm
4 pins with 0.1" spacing

回復  pizg
我差不多跟一般凡夫一樣,要花時間去搜查資訊,
那沒什麼偉大的,
幫助別人,其實是幫助自己,
...
vegewell 發表於 2014-3-24 02:03

我搜尋了不少網路上的資料,沒有人用DHT11做出攝氏溫度精度到小數點1位,
DHT11的溫度每次都是跳1度, 是否他的精度就是如此?哈~~DHT11誤差正負2度C,
難怪唷~~.
底下是DHT11的資料結構:
DHT11 data structure :

1.
Humidity Integer : 8bit

2.

Humidity Fraction : 8bit

3.
Temperature Integer :8bit

4.
Temperature Fraction : 8bit

5.
Check sum : Humidity Integer + Humidity Fraction + Temperature Integer + Temperature Fraction

DHT22好像可以到小數1位.

回復 3# pizg
我差不多跟一般凡夫一樣,要花時間去搜查資訊,
那沒什麼偉大的,
幫助別人,其實是幫助自己,
關於你另一問題,
憑你的本事,就能得到答案,
所以你該做的是-> 給自己信心.

回復  pizg
BZ水冷 溫度傳感器應該是一種 NTC溫度傳感器,

by
NTC熱敏電阻、探頭組(合)件.一種用熱敏 ...
vegewell 發表於 2014-3-23 02:57

感謝V大, 您真是神人.OK了.
在還沒解決這個問題之前,我還DIY了一條DS18B20的溫感線.
只讓他露出一隻腳來感測溫度,
其餘地方用熱熔膠"封裝"起來.

另提出一個問題,
DHT11溫濕度傳感器也是內建類似熱敏電阻的元件嗎?
請問有辦法讓他傳回的溫度值至少到小數1位嗎?
   

回復 1# pizg
BZ水冷 溫度傳感器應該是一種 NTC溫度傳感器,

by
NTC熱敏電阻、探頭組(合)件.一種用熱敏電阻外殼，延長引線，有時還用了一個接頭組合而成的成品熱敏電阻組(合)件。
利用NTC熱敏電阻在一定的測量功率下，電阻值隨著溫度上升而迅速下降。利用這一特性,
可將NTC熱敏電阻通過測量其電阻值來確定相應的溫度，從而達到檢測和控制溫度的目的。

這是電壓值的變化, 所以接 Arduino的Analog Input,
試試如下網頁所作:
Arduino: Analog Input NTC Thermistor 用熱敏電阻量度溫度.
http://miraigajettokenkyujo.blogspot.tw/2013/06/arduino-analog-input-ntc-thermistor.html
注意接法: