Post by thread:[EE] low cost air pressure sensor

Good day to all. Got a new project to work on that requires a low cost air pressure sensor. Expected pressure is quite low: 0 to 2" water column. Anyone have any favorite sensors that work over that low pressure range? Single port sensor is fine - I'm measuring pressure relative to atmosphere (gauge pressure). I've used Motorola's sensors in past but figure there has to be others available. Expected volume is quite low - maybe 1K per year. Thanks for any suggestions. dwayne -- Dwayne Reid <spam_OUTdwaynerTakeThisOuTplanet.eon.net> Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 22 years of Engineering Innovation (1984 - 2006) .-. .-. .-. .-. .-. .-. .-. .-. .-. .- `-' `-' `-' `-' `-' `-' `-' `-' `-' Do NOT send unsolicited commercial email to this email address. This message neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email.

I have a MOTOROLA FREESCALE MPX5010G\P1.45 PSI sensor going to a 18F1320. Like the 5 volt in, and 0 - 5 (I think it's something slightly less) volt analog out. Easy to connect, 3 little filter caps and you are there. It's remotely (3 feet away), potted it's port to a 1/4" pipe thread brass nipple with a hex for the wrench in the middle. Then the entire (vent port open) thing potted in epoxy with milled fiber glass filler. If it get exposed to the weather, no big thing. Don't know how you would connect to the port, piece of plastic tubing and a clamp (I use other places 2 wraps .035" stainless aircraft safety wire, then twisted tight). Check digikey for sensors that have pipe thread port already. And I thought Jameco had Motorola low pressure at low price, but didn't have the built in amplifier which would probably mean an OpAmp. Dwayne Reid wrote: {Quote hidden}> Good day to all. > > Got a new project to work on that requires a low cost air pressure > sensor. Expected pressure is quite low: 0 to 2" water column. > > Anyone have any favorite sensors that work over that low pressure > range? Single port sensor is fine - I'm measuring pressure relative > to atmosphere (gauge pressure). > > I've used Motorola's sensors in past but figure there has to be > others available. > > Expected volume is quite low - maybe 1K per year. > > Thanks for any suggestions. > > dwayne > >

Dwayne Reid wrote: > Good day to all. > > Got a new project to work on that requires a low cost air pressure > sensor. Expected pressure is quite low: 0 to 2" water column. > > Anyone have any favorite sensors that work over that low pressure > range? Single port sensor is fine - I'm measuring pressure relative > to atmosphere (gauge pressure). > > I've used Motorola's sensors in past but figure there has to be > others available. > > Expected volume is quite low - maybe 1K per year. > > Thanks for any suggestions. > > dwayne > That's a tough range to find "low cost" parts for. For your application, what does "low cost" translate to? I have been using SDX005IND4 from Sensym but it's a) 5" water column and b) $52 in 100's @ Digikey Low range air pressure sensors tend to have very poor temperature drift specs although this can be improved on with characterizing in an oven.

Pitot tubes with two temperature sensors? http://en.wikipedia.org/wiki/Pitot On 4/5/07, Dwayne Reid <.....dwaynerKILLspam@spam@planet.eon.net> wrote: {Quote hidden}> Good day to all. > > Got a new project to work on that requires a low cost air pressure > sensor. Expected pressure is quite low: 0 to 2" water column. > > Anyone have any favorite sensors that work over that low pressure > range? Single port sensor is fine - I'm measuring pressure relative > to atmosphere (gauge pressure). > > I've used Motorola's sensors in past but figure there has to be > others available. > > Expected volume is quite low - maybe 1K per year. > > Thanks for any suggestions. > > dwayne > > -- > Dwayne Reid <dwaynerKILLspamplanet.eon.net> > Trinity Electronics Systems Ltd Edmonton, AB, CANADA > (780) 489-3199 voice (780) 487-6397 fax > > Celebrating 22 years of Engineering Innovation (1984 - 2006) > .-. .-. .-. .-. .-. .-. .-. .-. .-. .- > `-' `-' `-' `-' `-' `-' `-' `-' `-' > Do NOT send unsolicited commercial email to this email address. > This message neither grants consent to receive unsolicited > commercial email nor is intended to solicit commercial email. > > -

Dwayne Reid wrote: > Good day to all. > > Got a new project to work on that requires a low cost air pressure > sensor. Expected pressure is quite low: 0 to 2" water column. > > Anyone have any favorite sensors that work over that low pressure > range? Single port sensor is fine - I'm measuring pressure relative > to atmosphere (gauge pressure). > > I've used Motorola's sensors in past but figure there has to be > others available. > > Expected volume is quite low - maybe 1K per year. > > Thanks for any suggestions. > > dwayne > > Maybe you could use "disposable" pressure transducers, used in hospitals for measuring bloodpressure (i.e. Baxter). -- cheers, Stef Mientki http://pic.flappie.nl

The Smartec pressure sensors costs about $5/pcs and are available in 0-0.35 bar, 0-1bar, 0-2bar, 0-6.5bar http://www.smartec.nl/pressure_sensor.htm hope it helps and those people have representatives in Canada. On 4/5/07, Dwayne Reid <.....dwaynerKILLspam.....planet.eon.net> wrote: {Quote hidden}> Good day to all. > > Got a new project to work on that requires a low cost air pressure > sensor. Expected pressure is quite low: 0 to 2" water column. > > Anyone have any favorite sensors that work over that low pressure > range? Single port sensor is fine - I'm measuring pressure relative > to atmosphere (gauge pressure). > > I've used Motorola's sensors in past but figure there has to be > others available. > > Expected volume is quite low - maybe 1K per year. > > Thanks for any suggestions. > > dwayne > > -- > Dwayne Reid <EraseMEdwaynerspam_OUTTakeThisOuTplanet.eon.net> > Trinity Electronics Systems Ltd Edmonton, AB, CANADA > (780) 489-3199 voice (780) 487-6397 fax > > Celebrating 22 years of Engineering Innovation (1984 - 2006) > .-. .-. .-. .-. .-. .-. .-. .-. .-. .- > `-' `-' `-' `-' `-' `-' `-' `-' `-' > Do NOT send unsolicited commercial email to this email address. > This message neither grants consent to receive unsolicited > commercial email nor is intended to solicit commercial email. > > -

> Got a new project to work on that requires a low cost air pressure > sensor. Expected pressure is quite low: 0 to 2" water column. Does "air pressure sensor" mean is/isn't there or you need to measure pressure in that range? For the former (on/off) depending on your tradeoff between mechanical and electrical costs you could use some form of bellows/diaphragm arrangement and a microswitch or similar. The truly Heath Robinson could also look at something similar with a spring and pot depending on requisite resolution etc. How many bits resolution do you need? What is the order of maximum acceptable cost? Russell

The application is to keep the pressure in a plenum constant at some user-defined value as outlet valves are opened and closed. The original approach was to monitor the state of the valves and apply offsets that approximate the load that the valves caused. While simple, its a pain to setup. Its actually kind of funny - that's how the job was originally presented: monitor valves and generate a DC signal that changes as the number of open valves changes. That's easy. Then they wanted to add trims to each input channel so as to affect how much change each valve introduces. This is to compensate for different sizes of valves. Still easy. Then make it so that the main board handles a small number of valves and add expansion boards as needed. Still easy but the packaging and interconnect logistics are starting to take their toll. And so on. Finally asked what the actual desired outcome of all this was. Answer: keep plenum pressure constant as number of open valves changes. OK, sez I, lets just monitor plenum pressure. As I mentioned in my initial post, I've used Motorola and Honeywell pressure sensors in past projects. However, they are a little too pricey for this application. Ideally, I'm looking in the Can $5.00 range or less. Anything more than Can $10.00 is just too expensive. The Smartec sensors mentioned by Vasile look to be exactly what I'm looking for. Thanks again to everyone for their suggestions! dwayne At 02:11 AM 4/9/2007, Russell McMahon wrote: {Quote hidden}> > Got a new project to work on that requires a low cost air pressure > > sensor. Expected pressure is quite low: 0 to 2" water column. > >Does "air pressure sensor" mean is/isn't there or you need to measure >pressure in that range? > >For the former (on/off) depending on your tradeoff between mechanical >and electrical costs you could use some form of bellows/diaphragm >arrangement and a microswitch or similar. > >The truly Heath Robinson could also look at something similar with a >spring and pot depending on requisite resolution etc. > >How many bits resolution do you need? >What is the order of maximum acceptable cost? -- Dwayne Reid <dwaynerspam_OUTplanet.eon.net> Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 22 years of Engineering Innovation (1984 - 2006) .-. .-. .-. .-. .-. .-. .-. .-. .-. .- `-' `-' `-' `-' `-' `-' `-' `-' `-' Do NOT send unsolicited commercial email to this email address. This message neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email.