When I was working on the temperature control feature of Lady Heather, I noticed that I could detect when ever I opened the refrigerator door (in the next room) or when I was in the same room as the Tbolt by looking at the EFC or temperature sensor plots... the Thunderbolt oscillator makes a nice thermometer. People are basically a 100 watt space heater. Another time I was working on a precision temperature recorder (based upon an Analog Devices V/F chip). It could easily detect when a person walked into or left a (rather large) lab. You could even quantify the number of people in the lab (one particularly large guy counted as two people). ----------------- > People would say "nice thermometer, guys :-(