Recommendation wanted for analog temperature sensing 0-512°C

I have an Arduino Mega2560 and need to measure temperatures produced in an approximately 1"D x 5"L tube over a 0-512°C range. I figure that 1/2?C resolution should be possible, but have no experience with temperature sensing.

I searched the forum for recent discussion and found http://arduino.cc/forum/index.php/topic,81464.0.html, but that discussion dead-ended without providing much sensor-related information. I looked at the OP's code and did a bit of streamlining to produce

/*----------------------------------------------------------------------------*/
/* Read reactor temperature (thermistor)                                      */
/* http://arduino.cc/forum/index.php/topic,81464.0.html                       */
/*----------------------------------------------------------------------------*/
int get_temp(void)
{  int i,t;                            /* Loop index and temperature variable */
   for (i = t = 0; i < 8; i++)         /* Until all 8 readings are summed     */
      t += analogRead(TEMP);           /* Accumulate 8 temperature readings   */
   return 0.1718 * t / 8.0 - 31.6792;  /* Scale and return average value      */
}                                      /*  end: get_temp()                    */
/*----------------------------------------------------------------------------*/

and although I recognize that t/8 is the average analog reading, I haven't a clue what the other constants are.

What I think I'm looking for are specific thermistor recommendations and some guidance in how to use them for the task at hand.

For anyone who might be interested there's an application overview at LENR Project

This looks a lot like a post i just answered :~

For your temerature i would use NTC probes like High temperature NTC ceramic resistors (ambient–1000 °C) - ScienceDirect (just googled this)

And map it like i said in the last post

+5v-------====----|------==|===-------GND
R10K | NTC 10K
|
Arduino analog

Something like this

Hmm - Ok, I'll add Y2O3–Mn2O3–Cr2O3 to my search list. :grin:

Hi Morris,

http://www.omega.com/ is a good resource if you haven't found it already.

jc

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1256768528

here is something about using NTC's on the forum

I think you will find that there are few temp sensors that can work reliably to that high a rating, other then thermocouples.

Lefty