Vasile Surducan wrote: > On 10/31/06, cdb wrote: > >> Option 1. Heated coil around water pipe / downstream thermister >> detection technique - measure temperature at coil and at thermister - >> work out rate of cooling = flow speed in Ltrs/minute. > > water's temperature does not count ? It does; you need differential measurement. I don't think thermistors are sufficiently precise, since you need pretty good synchronization between the two sensors, at least over the range of water temperature. Which might not be that much, so maybe you can calibrate thermistors sufficiently well. Gerhard -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist