On Sunday, 29 May 2022 00:21:48 EDT Chris Albertson wrote: > This would be the sensor I would use. The link below is a very > detailed gud that tells you how to use the sensor, including working > example software. > > https://learn.sparkfun.com/tutorials/sparkfun-qwiic-micropressure-hooku > p-guide > I've looked at that but I need an analog output I can op-amp up to the swing range I need. Mesa doesn't have an i2c interface that could talk to. I have some honeywell gage mode analogs coming from Mouser in that price range which can tolerate up to a 12 volt vcc, and that will help the noise budget considerably. But they won't ship till Teusday.
> Yes, it is an absolute sensor but air pressure on Earth does not change > that much/ If you really care a lot then use two pressure sensors, > leaving one open to the ambient air. (But that would be over the top, > nuts for an air mister) Agreed, just an offset to cancel the first 14.7 psia should work fine too. > The interface is easy to use I2C using the pseudo-standard "QWIIC" > connectors (physically JST connectors) The documentation is makes > using this easy. But where do I find an i2c fed D/A? I didn't note such a beast at Lady Ada's place. > On Sat, May 28, 2022 at 8:44 AM gene heskett <ghesk...@shentel.net> wrote: > > Greetings all; > > > > I'm getting frustrated, but I know it has to be out there, someplace. > > I need a differntial air pressure sensor, differential so it > > references local barometric as its reference zero, and up to 10 psi, > > with a 3 wire analog output. > > I've solved the control aspect, but not how to detect a pressure to > > accomplish the control. > > > > automotive EGR types seem seem the most promising as they are > > affordable and 2 port gismo's but all I can find just lists the > > vehicles it fits and works with, but zero info on how to hook it up > > and get an analog reading out of it. "MAP" sensors whose internal > > reference is a good vacumm can have their signals clipped and > > massaged into something usable, but so far I've bought 4 w/o finding > > a working one that actually reads the 14.7 psia of normal air. > > > > So how are you folks solving that problem? > > > > Or are you burning up the shop compressor feeding your misters? I > > can't see that as being an acceptible solution since none of those > > have an intake muffler so you can still hear yourself think. > > > > What I have cobbled up at the moment is giving me more than enough > > air to run a mister, and I can't hear it running over the 2 fans in > > this 6040 mill. One in the vfd is really noisy. > > > > Thank you. > > > > Cheers, Gene Heskett. > > -- > > > > "There are four boxes to be used in defense of liberty: > > soap, ballot, jury, and ammo. Please use in that order." > > > > -Ed Howdershelt (Author, 1940) > > If we desire respect for the law, we must first make the law > > respectable.> > > - Louis D. Brandeis > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
