04-03-2014 09:50 AM
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
04-03-2014 11:38 AM
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.
04-03-2014 11:46 AM
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
04-03-2014 12:39 PM
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
04-04-2014 02:57 AM
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
07-02-2015 02:15 AM
Sir can you tell me how to programm a arduino to measure the air flow in terms of CFM? any idea?
07-03-2015 07:11 PM
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
10-02-2017 01:35 PM
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