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Hey, I made a whistle.

A project log for VISP - Ventilator Inline Sensor Package

Bidirectional flow (volume), pressure, and temperature sensing in a single inexpensive I2C/SPI package.

Daren SchwenkeDaren Schwenke 05/02/2020 at 02:122 Comments

The venturi restriction plus the short tube going to the sensor was just the right geometry for a good whistle.  That was annoying.

I added another pickup tube in the venturi, and connected them.  I am thinking this will cancel the waves where they meet.  

As a last minute thought I made the geometry not symmetrical as well.  That might actually work against me now that I think about it.

Printing.

Edit: FFF version, the whistle was gone.  SLA version failed on first print due to low resin. It will be ready in the morning.

Discussions

chris wrote 05/04/2020 at 17:09 point

Why not just make an in-line barrier plate with some small holes to provide flow restriction?  Then just take the pressure difference from the two sensors across the barrier.  P2 - P1 = f(k) * flow rate  even if k is not linear it should still be a simple curve at these low pressures and low velocities.

Seems like all these venturis and pitot tubes and so forth are harder than they need to be...

  Are you sure? yes | no

Daren Schwenke wrote 05/04/2020 at 17:35 point

Yes.  Supposedly you lose less energy to the restriction this way.

  Are you sure? yes | no