Arduino + air flow sensor

Hello,

i am experimenting on some "special" project for Arduino. I would like to build a "night mask" (for mediatation - i saw this mask so there must be a way...). Scenario is simple, i must detect persons breathing, when 'breathing in' is in progress some lights on mask will turn on. When breathing in stops or persons starts breathing out light must go imediately off.

So the job is easy if i only know how to detect "air flow" ? :)

The mask i saw had some sensor about 1-2 cm below the nose (breathing must be through nose..)

Well i was exploring a litle but i dons really know if this is what i need. For now i found MPXV5010DP preasure sensor.

For me, more than a preasure (direction is important but with the preasure starts and stops can be detected).

Any ideas for simple solution? :)

If you want to do it with pressure you'll need about +-1cmH20 differential pressure, which is vastly smaller than the pressure range for the sensor you listed.

You really want something slightly in the nostril for this. Temperature will somewhat work, but you'll have some delay and a significant fudge factor around estimating where inspiration and expiration start & end.

thinking out loud, a small reed relay fixed an a magnet that only vibrates when air is flowing in one direction ?

The temperature sensor i, see http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.127.5161&rep=rep1&type=pdf or using something like this http://www.freepatentsonline.com/5676154.html[/url or as in this a movie http://www.youtube.com/watch?v=tYH8cO5RKHc or a gas sensor http://www.parallax.com/Portals/0/Downloads/docs/prod/sens/27904_279]30-1-2-GasSensor-v2.2.pdf or ... just googled: breathing sensor 5V

rob

Try a small cermet microphone. The sound of air inhalation and exhalation without apparent snoring will amaze you. The sounds of each are quite different and the arduino can easily determine which. jack

very interested in all ideas for now :)

I like the the simple idea about the temperature sensor, maybe i will try this, but the problem here could be the delay yes... (cca 0.5s would be ok) but don't know if this sensors are/react so fast...

the microphone on the other hand would probably be 'instant' on changes detection. But don't know how will i sample the voltage with arduino to decide whether is this inhale or exhale..? also question what will happen if there is some room or outside noise present..

The transition from inhalation to exhalation will be easier to detect.

The exhalation to inhalation transition will be more "iffy", and the crossing thru the average may put you within a second.

If you just wanted transitions, maybe you could devise a little flap that when you breathe in it breaks a circuit and when you breathe out it connects the circuit.

How is the project moving on? :)

I am trying to think of something similar. What about using thin stripes of cut-up paper or aluminum and somehow exploiting their movement when exhaled upon? (Via the pressure sensor?)