There was a discussion on using incandescent micro-lamps as
temperature sensors two years ago with Wagner Lipnharski and Roman
Black.

I experimented a little with 60V-50mA lamp - small glass tube with two wi=
res:
- 120 Ohm at 25C;
- 155 Ohm in boiling water;
- At 250C, I guess, its resistance would be aprox 200 Ohm;

At 10ma current the voltage range would be ~ 1mv=E2=80=932mv =E2=80=93 pr=
etty enough
to get it amplified by some Op Amp to, say, 2v=E2=80=934v suitable for PI=
C's
ADC.

 Glass tube provides better stability than exposed element, I think.
Time constant of temperature drop was about 10s.

That's just an option. Dedicated device is better, of course.

Regards,
Mike.

_______________________________________________
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist