Measuring air flow with Arduino ?

[DavePW]

Folks - Looking for some ideas re how you could make a simple air flow measuring device with Arduino that didn't necessarily need any calibration. Looking at a range of say 5 - 30 metres/second. Accuracy doesn't have to be too good, say +/- 2 m/s

Any thoughts?

cheers

dw

[Nathan_B.]

Most sensors should be calibrated but if you don't care too much about the accuracy, you can generally get away with using the factory calibrarion.  You simply need to find a transducer (designed for air flow in your application) that outputs a voltage between 0 and 5 volts.  Then, with LIFA you simply read the voltage of the analog pin and convert the voltage to the appropriate engineering units.

[DavePW]

Thks Nathan...

I was rather hoping that some clever guy had worked out some method to do this other than using off the shelf meters. I've been looking at a couple of methods, one using pairs of ultrasonic transducers either side of the pipe and another measuring the change of temperature of a heated filament in the pipe.

dw

[hrh1818]

Most Air Velocity sensors are designed for industrial applications and most likely won't fit your budget.  However, You could build a DIY air velocity sensor using two pressure taps and a differential pressure transducer. See the following link for theory.

<https://www.dwyer-inst.com/Products/AirVelocityIntroduction.cfm>

For differential pressure you could use two barometric pressure sensors such as the following.

<https://www.sparkfun.com/products/9721>

hrh1818

[DavePW]

Thanks hrh1818...

Differential pressure would certainly be a way to go... I'm trying to see if there is something I can do external to the pipe being monitored. So the ultrasonic idea seemed to have merit...

dw

[Bhanu2821]

Sir can you tell me how to programm a arduino to measure the air flow in terms of CFM? any idea?

[hrh1818]

CFM implies fairly large volumes of air flow and suggest the use of an orifice and a differential pressure measurement.

See: <http://www.efunda.com/formulae/fluids/calc_orifice_flowmeter.cfm> for an example that uses an orifice plate and a differential pressure measurement.  See <http://www.phidgets.com/products.php?category=3> for a differential air pressure sensor.

hrh212

[omega_io]

here as an article on this topic using AMS 5915 differential pressure sensor and Arduino. This pressure sensor comes with 2 nozzles and its output is digital.

https://ncd.io/differential-pressure-sensor-arduino/

Thanks