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Air Flow Meter? — Parallax Forums

Air Flow Meter?

eod_punkeod_punk Posts: 146
edited 2010-08-19 11:00 in General Discussion
I was asked about getting an air flow meter at work and was wondering if anyone has interfaced one with a Prop or a Basic Stamp. I am interested in measuring flow and a totalized flow. If anyone has any links or has tried something similar I would appreciate some info.

Comments

  • John R.John R. Posts: 1,376
    edited 2010-08-18 10:21
    Just as a smark aleck question, are we talking wind speeds (weather), office/plant airflow, or "explosive blast" air flow?

    Totalized flow implies a "captive" air flow, through a duct or other passage where some assumptions can be made based on measuring velocity (or pressure) in a given location and extrapolating from there. What's the set up here?
  • eod_punkeod_punk Posts: 146
    edited 2010-08-18 11:13
    Sorry I should have specified. We are hooking up an air hose from our air compressor for a test and would like to know how much flow we have and how much we used.
  • John R.John R. Posts: 1,376
    edited 2010-08-18 12:00
    eod_punk wrote: »
    Sorry I should have specified. We are hooking up an air hose from our air compressor for a test and would like to know how much flow we have and how much we used.

    Whole different ball of wax that what I was thinking.

    There are two types of flow meters I'm familiar with for this type of app, and hopefully someone else will have a better idea.

    Type "a" is a ball inside an inverted cone shaped opening that the air goes through. The higher the ball is "pushed", the more air is flowing. Type "b" is the same principle, but has a spring loaded plug inside the cone, and has a magnetically coupled sleeve outside the flow path. This whole thing is inside a clear plastic sleeve. You might be able to monitor either with somethign like the line scanner or some type of magnetic (hall effect) sensor.

    Other than monitoring flow against time, I'm out of ideas on how to totalize the flow.

    I've got to believe that there is an electronic version of something like this out there, but haven't come accross one.


    John R.

    (I was secretly hoping for a really "fun" application...)
  • kwinnkwinn Posts: 8,697
    edited 2010-08-19 09:13
    If the ball or plug John R. is refering to is magnetic then you could use 3 coils to sense the ball or plug position. The center coil would be energised with an AC current, which would induce a current in the 2 surrounding coils. The ratio of the voltages induced in the 2 coils would be dependent on the position of the ball or plug.
    The linear sensor approach would be simpler, and works regardless of the material the ball or plug is made of. Also easier to calibrate.
    Totalised flow is simple to calculate as it only requires dividing the individual readings by the time period between readings and summing them, or summing "x" readings and dividing by "x" times the time period between readings.
  • Spiral_72Spiral_72 Posts: 791
    edited 2010-08-19 09:29
    Would a mass airflow sensor work off an automobile? I dunno if you could find a data sheet though
  • eod_punkeod_punk Posts: 146
    edited 2010-08-19 11:00
    Thanks for the suggestions, I'll keep them in mind but I think the project has been cancelled.
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