I am trying to measure air temperature and tried using a thermistor it worked but slowly. The thermistor took about 5 minutes to go from 80*F to 40*F is there any way to get air temperature in about 1 second ?
What are you trying to do??
If you are trying to do the unusual thing of measuring air temperature that CHANGES QUICKLY that's a lot different than typical slowly-changing air temperature.
Some info here: http://arduino-info.wikispaces.com/Brick-Temperature-DS18B20
arduinopi: is there any way to get air temperature in about 1 second ?
Usually, the air temperature only varies slowly and the sensor gradually settles to the same temperature as the air. This is fine for tracking temperatures that only change slowly.
If you have a temperature that changes quickly there are a few ways to do it. You can add a foil heat sink and use an infra-red sensor to measure the surface temperature. That would respond pretty quickly, but would need some care to make it robust. If the air temperature is changing because the air is being replaced then an open bulb style thermister in the air stream will respond pretty quickly. I use one in an air stream moving at around 100 ms-1 and it responds in tenths of a second. But it is very sensitive to air speed - in still air, it will only respond very slowly.
1 second is hard and would take some work, but if you want to beat 5 min, that can be done easily.
The last sensor I used was the one linked below. It would change from 70F to 90F in about 5 sec.
Make sure you have as much airflow as possible. I added a small fan to my project and it helped a lot with lag time and the accuracy of my results.