On Mon, 08 Feb 2010 19:09:03 +0100, "Dario Greggio" said: > Alex Harford ha scritto: > > On Mon, Feb 8, 2010 at 2:00 AM, Michael Rigby-Jones > > wrote: > >> What kind of range of airflows do you need to measure? Perhaps an > >> automotive air mass sensor would be usable? > > > > That's exactly what I was thinking. What kind of airflow do you need? > > > > Early this morning I've received an Offer by Sensortecnichs - > some 90EUR for a 0-5V sensor, capable of 1-2bar and 360 lt/hour. That's probably a good choice. It's hard to make an airflow sensor measuring low flow rates. Automotive MAF sensors are for hundreds of times as much air. Back to the one that used two transistors heated to 50C. I built that many years ago when it forst appeared, because it was charming. Although it does work, plain transistors are awful. There is too much thermal mass. It takes a minute to stabilize and response to changing flow rates was wobbly. Cheerful regards, Bob -- http://www.fastmail.fm - The professional email service -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist