Humidity and temperature measurment

I like to built an humidity and temperature controller using DHT22 sensor.
I this sensor their is only one data pin which used to connect with the controller...
By connecting one pin to the controller how to read the both humidity and temperature..?

Hi,

A simple internet serach brings a lot of results. With textual description and code examples.

Klaus

DHT22 uses One Wire Protocol to Communicate. If your Compiler has One Wire library then you can use it else you have to write your own One Wire library.

Which Compiler are you using ?

You should pull-up the One Wire Communication pin to 5V using a 4.7k resistor.

After reading the data which contains both temperature and humidity data you have to split them and use them.

KlausST said:

Hi,

A simple internet serach brings a lot of results. With textual description and code examples.

Klaus

Click to expand...

I searched in google I found lot of tutorials but they used inbuilt libraries in arduino and they measured temperature and humidity.
I like to use PIC18F4520 controller.

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baileychic said:

DHT22 uses One Wire Protocol to Communicate. If your Compiler has One Wire library then you can use it else you have to write your own One Wire library.

Which Compiler are you using ?

You should pull-up the One Wire Communication pin to 5V using a 4.7k resistor.

After reading the data which contains both temperature and humidity data you have to split them and use them.

Click to expand...

I'm using PIC18F4520 with MPLAB X IDE 3.36 compiler.

Each data comes one by one like 1st data is temperature and 2nd data is humidity like that or something else..?

- - - Updated - - -

baileychic said:

DHT22 uses One Wire Protocol to Communicate. If your Compiler has One Wire library then you can use it else you have to write your own One Wire library.

Which Compiler are you using ?

You should pull-up the One Wire Communication pin to 5V using a 4.7k resistor.

After reading the data which contains both temperature and humidity data you have to split them and use them.

Click to expand...

I'm using PIC18F4520 with MPLAB X IDE 3.36 compiler.

Each data comes one by one like 1st data is temperature and 2nd data is humidity like that or something else..?

Hi,

you didn´t mention PIC in your first post.
Anyway, an internet search for "DHT22 PIC" gives more than you need to make it work: Documents, example code, application notes (even original Microchip ones), even youtube tutorials.

And if you just look at the arduino code, then you will have 80% of information, and the complete program flow.

Each data comes one by one like 1st data is temperature and 2nd data is humidity like that or something else..?

Click to expand...

No one of us will know these things better than the datasheet.

--> I don´t see the need for a "global question" about DHT22 with PIC communication. Read the datasheets and go through the internet informations.
Then you are welcome to ask elaborated, detailed questions. Show us what you have done so far. Refer to documents.

Klaus

DHT22 is old massive sensor with poor accuracy and weird interface. I prefer bosch's BMP180/280

Hi,

I once tested HTU21D.
The first results were good.

Klaus

The accuracy of DHT22 is rather low, one can build an indicator rather measuring device using that sensor. I did good experience with Honeywell HIH-6130/6131

hello,

I tested a DTH22 AM2302 during any days, with loggin data..

This One Wire Sensor has problem of delay for reading bit , if interval of measurement is to short ..
With interval of 500mS , i get 2% error ( on >15000 measures), due to bit reading timeout delay ( with a timeout of 25µS !)
specsheet data page 7 :
*Collecting period should be : >2 second.

i modifiied my acquisition periode to 2000mS => No more error..
Accuracy seems correct ..

What is your reference for humidity measurement?

DTH22 is a decent sensor for those who are starting with microcontrollers and sensors, I used it a lot because is also cheap and very easy to implement