first, thanks > The gas chromatograph has to to hooked to something, > some kind of sensor at the other end. Mass Spec is a > common macro sized instrument used with a GC. I dont > think anyone has a miniture MS. We have stuff like > tunable laser diodes that detect water spectra (for Mars > subsoil), and relatively small thermal emission spectroscopes, > but not in silicon as such. You can fish around in our > web sites and see what they are pitching this week. Sorry > I cant find the exact page, so start at www.jpl.nasa.gov > as far as hooking the gas chromatograph to something,--- the one that I used before had a suction tube that periodically took a sample, and then does what a chromatograph does and made a plot, I don't understand what you mean by saying that the chromatograph 'has to be hooked to something'??? AND > I am not a sensor guy, I am a battery guy, which may be of some > help to people on this list. I am TRYING to become a PIC guy too. I'm not a microcontroller pro either, and for what it's worth, after beating my assembly language head against the wall, I finally got a compiler, and started to make some faster and less frustrating progress on my pic projects. From one new-picster to another... Thanks, I'll check out the web for sniffers cheers -- rad0 -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.