At 07:18 PM 12/31/01 +0200, Peter L. Peres wrote: >Happy New Year everyone. > >Dwayne, thank you for the detailed description, I am looking forward for >more details later. > > From what you describe there seems to be a lot of hardware involved ... >I'll probably try it the nasty way: > >A/D less PIC, sensor transistor mounted as common emitter amplifier and a >cap between C and gnd, and a R to a PIC IO pin. And a good quality voltage >regulator (a Seiko probably). Maybe I'll replace the PIC side resistor >with a JFET, and bridge it with a large R, this has worked well in the >past (with Up < 2V), to improve A/D linearity. This sounds interesting - I'm looking forward to hearing your results! But I'm curious: will the calibration change if you use a different transistor as the sensor? I was looking for something that would not require re-calibration if the sensor was changed. >How much precision did you achieve ? I only displayed whole degrees C - I wasn't trying for anything better. The spot checks I did were within 1 digit of my lab K-type thermometers (both recently calibrated) - that was as good as I ever hoped to achieve. The project was originally going to use thermistors but I wanted to try something different. I got it working but then the whole thing got put on the shelf - the client had other (higher priority) projects. But I'll be resurrecting it soon. dwayne Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 17 years of Engineering Innovation (1984 - 2001) * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Do NOT send unsolicited commercial email to this email address. This message neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email. -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body