Trouble with DHT11 Library (MSP430G2553)

[fastbiter 0]

Hey guys,

I am trying to work with this library: http://forum.43oh.com/topic/2239-solved-dht22-temp-rh-one-wire-sensor-on-energia/?p=19474

 

To my knowledge, everything is configured correctly. I have confirmed that the device does work fine on an Arduino Uno with this resistor, 10k. I have also confirmed that it works with a 4.7k. It also works with both 3.3v and 5v.

 

However, on the MSP430, using the above library (stock) the values I am getting are very wrong, for example:

debug 	bits received 	40
debug 	27, 0, 11, 0, 38 =? 38
debug 	 checksum 	ok
debug 	RH% 	9984
debug 	oC 	4352
RH% 	998.4 %	
oC 	435.2 *C

This is in a room ~62F % 40% RH. If I touch or blow on the sensor the values change as you would imagine, so I know that it is reading something and reporting changes properly. I have looked through the code and nothing glaringly obvious sticks out at me. I know I could measure a few reference values and add in a few calculations to adjust the output, but I would rather fix the root of the issue. I understand the library was written for the DHT22 and I am using the DHT11, but they should be drop-in replacements for one another, the DHT22 just being more sensitive. Again, I have used this unit with a DHT22 library on Arduino.

 

I would greatly appreciate any help! I have researched this for a while but have found nothing - it's possible that I'm just not using the right terms, however.

 

Thank you!

[bluehash 1,581]

@@fastbiter

 

Hey guys,

I am trying to work with this library: http://forum.43oh.com/topic/2239-solved-dht22-temp-rh-one-wire-sensor-on-energia/?p=19474

 

This is in a room ~62F % 40% RH. If I touch or blow on the sensor the values change as you would imagine, so I know that it is reading something and reporting changes properly. I have looked through the code and nothing glaringly obvious sticks out at me. I know I could measure a few reference values and add in a few calculations to adjust the output, but I would rather fix the root of the issue. I understand the library was written for the DHT22 and I am using the DHT11, but they should be drop-in replacements for one another, the DHT22 just being more sensitive. Again, I have used this unit with a DHT22 library on Arduino.

 

I would greatly appreciate any help! I have researched this for a while but have found nothing - it's possible that I'm just not using the right terms, however.

 

Thank you!

 

According to this, the DHT11 or DHT22 *may* have different formats.

In the Adafruit tutorial, they mention about enabling the DHT11.. did you do this? I have neither, so this is just from reading:

 

 

If you're using a DHT11 sensor, comment out the line that sets the type:

 

//#define DHTTYPE DHT22 // DHT 22 (AM2302)

 

and uncomment the line that says:

 

#define DHTTYPE DHT11 // DHT 11

 

HTH.