DHT22

DHT22 and Arduino uno. i read that we have to connect to pwm pin. but all examples connect the signal pin of DHT22 to pin 2 or 7 of the Arduino UNO.
So, can we use no PWM digital pin? and why?
Thank You!

DHT22 and Arduino uno. i read that we have to connect to pwm pin

Where did you read that ?

can we use no PWM digital pin? and why?

Yes you can because the DHT22 does not need to be connected to a PWM pin.

pikachu91:
i read that in some web. but if not pwm, how can the digital pin read the sensor value?

Why do you think that the Arduino pin needs to be able to output a PWM signal in order to read the sensor ?

A PWM pin outputs a variable duty cycle signal the duty cycle of which can be varied between 0% and 100% by using a value of between 0 and 255 using the analogWrite() function. None of this is applicable to reading a DHT22

Are you perhaps confusing an analogue input with a PWM output ?

The DHT22 contains an integrated circuit as well as the temperature and humidity sensors which allows it to communicate with the host microcontroller using a digital signal. If you want to see the dreatils of how this is done then look in the DHT library files

Here is a small sample

    // Now read the 40 bits sent by the sensor.  Each bit is sent as a 50
    // microsecond low pulse followed by a variable length high pulse.  If the
    // high pulse is ~28 microseconds then it's a 0 and if it's ~70 microseconds
    // then it's a 1.  We measure the cycle count of the initial 50us low pulse
    // and use that to compare to the cycle count of the high pulse to determine
    // if the bit is a 0 (high state cycle count < low state cycle count), or a
    // 1 (high state cycle count > low state cycle count). Note that for speed all
    // the pulses are read into a array and then examined in a later step.