How to measure inhaled air speed

[Asheers]

I want to make a device that would be able to measure inhaled air, but not sure how to go about it.
I know you can buy a spirometer but I was hoping to make a cheaper version of this.
Any help is much appreciated

 

[BradtheRad]

You certainly do not want to make it difficult to take a breath. This reduces your list of devices.

About the only method I can think of is to position a tiny pinwheel at each nostril. It must be friction free. It must have a guard ring around it, so the blades do not contact skin accidentally.

The pinwheel will spin one way when inhaling, and the opposite way when exhaling. I can't think of an easy hookup for taking electronic measurements of its speed. Maybe reflected light?

It won't be accurate, unless everyone's nose is the same size.

My idea seems ludicrous, I admit. It's just brainstorming. Not very workable. Nevertheless such brainstorming can lead to something that is workable.

 

[chuckey]

If you build a soft nose mask out of silicone rubber and terminate it in a tube, then you could build a hot wire anemometer into the tube, as all the input and output air would have to flow through the tube.
Frank

 

[ads-ee]

Both of you are assuming the OP wants to do this through nose breathing.

I've been to a doctor's office and had to blow (was making wheezing noises when breathing) into this plastic thing that had some sort of paddle wheel think inside that the doctor looked at when I blew that measured the amount of airflow by what position it ended up in.

Not sure how accurate something like that is, but it seems to work reliably as they had me do it 3 times (primarily because he couldn't believe that I could move that much air, above average, and be wheezing!).

I suppose that just means I'm full of hot air ;-)

 

[jiripolivka]

Medical devices to evaluate lung capacity can use sophisticated sensors, but you can build a simple "flap in a pipe" sensor which can be calibrated in a flap angle vers. air speed in the pipe.

 

[chuckey]

As my suggestion, less the nose bit. I had one of the lung capacity tests and the display was direct on a CRT and the nurse by pressing some keys showed my previous test. I was recovering from pneumonia.
Frank