XPost: sci.physics   
   From: g@a.b   
      
   On 29/10/2011 21:23, Morris Dovey wrote:   
   > On 10/29/11 11:09 PM, Morris Dovey wrote:   
   >   
   > Argh!   
   >   
   >> * If anyone would like to play along, I could use some help with a   
   >> combination heater/temperature sensor using an up to 16-inch (406.4mm)   
   >> nichrome wire threaded through ceramic cores (inside a 1/4x4-inch copper   
   >> tube that's closed on one end) with one side connected to ground and the   
   >> other to a SPST relay so that when the relay is powered,   
   >   
   > SPST should have been SPDT! Sorry.   
   >   
      
   Not to discourage your effort, but I think using the Arduino to read the   
   resistance of the wire might be too inaccurate. You are basically   
   engineering a temperature measurement system from scratch. Lots of   
   testing needed first before implementing the thing.   
      
   And mixing AC and DC makes me shudder. At least use a scope to check   
   that no harmonics/noise from the AC side sneaks up on the Arduino   
   circuitry...   
      
   Why not use a thermocouple? These sensors measure really high   
   temperatures. As a start, look at http://www.sparkfun.com/products/306   
      
   Good luck.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)