I want to make air flow sensor

Sorry Imam, I don't understand what you mean by

" in natural windows ".

I think we may have lost something in transaltion here.

Could you add a sketch to show us what you need to do.

Thanks.

MK

i mean natural ventilation

sorry for my bad in english

I found this during my literature review (link below), I want to make somethink like this but to measure air velocity at natural ventilation. And I think its need some modification cause the differential pressure must be very low.

do you have any suggestions

https://www.instructables.com/How-to-Make-an-Air-Flow-Rate-Sensor-With-Arduino-a/

Thanks

IS

I'm still not sure that I really understand what you want to measure.

For low airflows a hot wire or hot film anenometer is probably the best bet.

Ultrasonic may be possible as well.

But unless you describe the measuring problem in alot more detail (with sketches or drawings and some idea of the measuring range)  then it's not easy to give good advice.

MK

Welcome sbrn . From your profile I see you are new to the community, so again welcome.

I have no doubt someone in our community will have a solution to your problem. I appreciate the language barrier might create some issues. The community members are diverse. My experience is that language hasn't stopped anyone so far from getting their answers.

Can you share some details about your background. Education, experience and/or knowledge level. This sites contains a wide variety of experience. Software, hardware, mechanical, electrical... You name it and there is  someone who can speak to it.

Your challenge is to provide a question with the right bait to attract their attention to get your answer. Be careful, if you are trying to get the community to do the work for a school project, someone will twig to it and stop the conversation. Starting with a user profile helps some people offer advice. If you have no microcontroller knowledge then someone giving you a PLC solution might prove difficult.

Help us, help you.

So what you have is two design challenges, namely air flow speed and air flow direction. I would suggest starting with the simpler? design challenge of finding a solution that can determine direction of air flow before getting to measure air flow speed. As you say this could be determined be measuring the slight pressure difference between inside and outside of a building but that you cannot find a sensor sensitive enough.

In my view, if a sensor cannot be found then the trick is to design a method to channel the air flow through a tighter space to increase the pressure difference. As that article demonstrates, this usually means making a separate enclosure or housing for the sensor of choice to provide you with more meaningful data. As to how this is done in the real world - well, unfortunately, I don't have an immediate answer.

The Element14 community is great! Thanks.

I've never heard of hot wire or hot film anemometer, an idea from the year 1914 . The idea is really intuitive, it makes me want to incorporate something similar to the project that I am preparing for Design for a Cause Challenge.

Reading about how it works I wonder if it would be feasible to do the same taking advantage of the heat generated by a cheap gas sensor with heater like the MQ-135 and turning the sensor with a motor in certain steps to obtain both speed and direction.

I couldn't easily find a good DIY hot wire sensor but I found these which might help.

https://www.youtube.com/watch?v=rCzw6ottMe4

https://www.youtube.com/watch?v=0hBBH4n5wuU

MK

Seeing is now believing. Wow cool.