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Where to find Air and Water Pressure Sensors — Parallax Forums

Where to find Air and Water Pressure Sensors

BadDogBadDog Posts: 13
edited 2004-10-18 14:27 in BASIC Stamp
I am looking for sensors for monitoring air and water pressure in storage tanks and lines.· I can't seem to find any sensors like those on the Parallax site.· Any help appreciated.·

Comments

  • MatthewMatthew Posts: 200
    edited 2004-10-17 19:35
    Google this sensor:
    Motorala MPXA4110A

    Hope that helps!
  • BadDogBadDog Posts: 13
    edited 2004-10-17 19:42
    I get no results with that number.
  • MatthewMatthew Posts: 200
    edited 2004-10-17 19:47
    Oops. Try this link:
    http://www.freescale.com/files/sensors/doc/data_sheet/MPX4100A.pdf
  • BadDogBadDog Posts: 13
    edited 2004-10-17 19:52
    Thanks for the link. What I really need is something that can plumb into a compressor line/tank and one to plumb into a water line/tank. Any ideas for that?
  • MatthewMatthew Posts: 200
    edited 2004-10-17 21:34
    Sorry, no ideas from me. I'm completely new to the stamps, and only know the few sensors I plan on using for my project.
  • cyberbiotacyberbiota Posts: 79
    edited 2004-10-18 02:26
    BadDog-

    Motorola (now FreeScale) make fine sensors.· SenSym (now Honeywell) makes an excellent series of gage, differential·and absolute pressure sensors, as does Honeywell under their own name.· All can be found in a variety of form factors, fluid/gas resistance and various temperature compensation/signal conditioning options.··Pressure sensors·are in·section 'N', pp 1223-1226 (catalog TO41, April '04) of the Digi-Key catalog.· Beware that·pressure sensors·are expensive, very intolerant of reverse polarity connections and·sensitive to pressure excursions beyond the rated limit (and I'm not talking burst pressure- get close to that, and they will never be accurate again).· Good luck and have fun.

    peter

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Dr. Peter C. Charles

    Director, Research and Technology
    CyberBiota, Incorporated
    Peter.charles@cyberbiota.com
    http://www.cyberbiota.com
  • BadDogBadDog Posts: 13
    edited 2004-10-18 02:59
    I was suprised at the price of the pressure sensors I did find ($300-$500 range) and thought I must be missing something. What I am trying to do is monitor water and air pressure to make sure water pumps and compressors are working at remote locations. I am not that concerned with accuracy. Is there a inexpensive solution if I forego accuracy? Thanks.
  • cyberbiotacyberbiota Posts: 79
    edited 2004-10-18 03:16
    BadDog-

    Much of the price is determined by the form factor (30 pitch British Pipe Thread), the casing (314-L medical grade Stainless), fluid contact surface (all teflon membranes) and pressure range (>100 psig).· If you want a screw-in solution·to measure 300 psig of a corrosive fluid, you are gonna need to fork over a couple of vital organs.· If you are willing to do your own plumbing, are working in the 0 to 10 psig range, and are measuring air or water, a 15 dollar sensor will do the trick.· Take a look at what digikey has to offer.· If nothing suits your needs, contact me offline and I will hook you up with something that will do the trick.· We use LOTS of them for low pressure air and water measurement.

    peter



    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Dr. Peter C. Charles

    Director, Research and Technology
    CyberBiota, Incorporated
    Peter.charles@cyberbiota.com
    http://www.cyberbiota.com
  • BadDogBadDog Posts: 13
    edited 2004-10-18 03:49
    I am measuring in water and air in the 0-100psi range. I suppose 1/4" thread would be the easiest case to work with, and they appear to have those. I think with the basic 2 stamp I need 0-5vdc output. I looked at the digi-key catalog and it looks like I am can use one of there sensors, but they are still around $100 each (and I need several). Wow, I assumed they would be in the $10-$20 range. I suppose pressure switches might be another approach since I am trying to use it to tell me when pressure drops below a certain level to indicate problems with pumps and compressors. Although it would be nice to monitor actual pressure values.
  • BadDogBadDog Posts: 13
    edited 2004-10-18 04:21
    I wonder if I could use an oil pressure sending unit and set it up to do the same thing. Something like this: http://www.measureanything.com/products/22601-5758/catalog_22601-5758_sensors_pressure.asp It is based on resistance so I assume I would have to do a bit more wiring etc... but the sensor is a lot less expensive. Any thoughts.
  • cyberbiotacyberbiota Posts: 79
    edited 2004-10-18 04:40
    I am not familiar with·VDO Oil Pressure Senders, but for $18.19 you can get a Motorola MPX5700GP-ND (digikey number) that will measure to 101.5 psig and give you a 0- 4.7V output.· You will have do do a bit of plumbing, as it is a barb fitting rather than NPT/BPT/compression.··A screw-in solution would be ideal, but if you only have 2 or three to do, it might be worth it to save 250 dollars.

    peter



    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Dr. Peter C. Charles

    Director, Research and Technology
    CyberBiota, Incorporated
    Peter.charles@cyberbiota.com
    http://www.cyberbiota.com
  • BadDogBadDog Posts: 13
    edited 2004-10-18 04:48
    I can do a little plumbing. Thanks for pointing out that particular sensor.
  • SPENCESPENCE Posts: 204
    edited 2004-10-18 13:39
    How about using automotive oil pressure sensors? They start out at about 6-8 dollars and up in various ranges

    spence
    k4kep
  • nick bernardnick bernard Posts: 329
    edited 2004-10-18 14:27
    http://www.electronicsurplus.com/commerce/catalog/product.jsp?product_id=86335

    i found this site in a minute or so just to demonstrate the product and not to reccomend a specific retailer

    my company buys and installs hobbs switches to monitor vital engine systems; i.e. oil/water pressures in cost sensitive situations

    i·think they are sold preset to a specific pressure set point.

    also with contacts you can supply your own·voltage signal which is a major plus if line losses may be a problem.



    roxon

    nick bernard
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