While I've not used the DHT11, I have heard enough about it to state that it is notoriously unreliable. The tolerances on its measurements are fantastically huge. IIRC its readings can deviate ten or more degrees Celsius from the actual temperature!

Might I recommend the DHT22 aka AM3202? It /is/ more expensive, but by the same token, it's actually usable... mostly because it stays within far more reasonable tolerances as far as measurement is concerned.

Thanks for hint. Definitely tolerance with in the range few deg are not acceptable.

I'm just looking on the price of DHT22 and it is around 2.5$, much more expensive then DHT11 but still it is acceptable. Thank you one more time.

Glad to help!

...yeah, I knew it was more expensive... there may be other/better modules out there. The DHT-series parts use a weird protocol anyways, IIRC... I'm still on PICAXE microcontrollers, I haven't graduated to Arduino yet -- but you have to overclock the heck out of a PICAXE (32MHz and /really/ dirty circuit tricks, or 64MHz and "only slightly dirty" circuit tricks) to get anywhere near the bit rate needed to communicate with DHT-series parts.

One more thought -- Sparkfun Electronics sells the TMP36 sensor. (I haven't checked prices or availability elsewhere.) They're pretty enthusiastic about it and it looks easy enough to use -- it requires one external component, a 100nF (0.1uF) capacitor, and its output is an analog voltage proportional to the temperature in degrees Celsius -- 10mV (0.01v) per degree C.

https://www.sparkfun.com/products/10988 would be the Sparkfun product page.

Good luck!

Thanks for this link!

You can buy DHT11 on aliexpress.com for 0.69 USD.

And also, you can add what would be a cost in bulk.

http://www.aliexpress.com/item/1pcs-lot-free-shipping-DHT11-Digital-Temperature-and-Humidity-Sensor-DHT-11-For-Arduino/32639839673.html?spm=2114.01010208.3.1.jMbs47&ws_ab_test=searchweb201556_6,searchweb201602_5_10017_10005_10006_10034_10021_507_10022_1003...