I have a room that will be kept cool by a fan blowing external air into the room. I believe blowing air into the room could have the result of keeping the room positively pressurised, because the room is pretty much sealed, except for a small exhaust port, but I want to prove my theory to be sure.
So, my question. Is there an air pressure sensor I could connect to an ESP32 or ESP8266 to measure the air pressure in the room? With the theory being the air pressure might be higher when the fan is running?
However, if you only need to know if the room is positively pressurized and arenāt looking for a quantitative measurement, Iād recommend trying something simple ā maybe run a transparent tube through the exhaust port, fill it with water and see if the water level outside of the room raises when you turn on the fan.
Great to hear from you and Merry Christmas. Turns out I have one of these, but wasnāt sure if it would be suitable for the job. I can give it a go and see what happens.
You would need two barometers calibrated exactly the same to get that to work.
Otherwise you will only get the rooms air pressure but you wonāt have a clue if itās more or less than normal.
What Ondras suggested is a normal procedure to figure it out.
You donāt actually have to compare it with the outside, you just paint a line where the water level is then the level should change if there is a higher pressure.
However, i highly doubt you have a higher air pressure in that room, as long as there is an exhaust then you wonāt get a higher air pressure except in the very tiny amount barely measurable.
At work we have a room that we have pressurized, and that room is sealed and has a fairly large industrial fan to get the positive air pressure.
We get about 2 hpa higher than outside the room. We have two probes measuring, one inside the room and one outside and the value is subtracted.
A normal air pressure is about 1000 hpa, and we manage to get 0.2% higher air pressure with professional people installing it and with an industrial fan and a room that has been intentionally sealed by professionals.
In my opinion, donāt put to much money in to this project unless there is some real benefit of knowing.
If itās just curiosity, then go for a tube and a pen.
The origins of this idea was an attempt to non-invasively detect the fan was runningā¦ the thinking being, if there is positive pressure in the room the fan is on. Based on your comments I may be going down the wrong path, so may need to work out another way to detect the fan is on and blowing.
How strong is the fan?
There are micro switches that require very little to be pushed.
If you mount/glue a large thing on it to catch the wind then perhaps the wind from the fan is enough to trigger the switch.
This is not something I have tried so it could fail miserably.
Hi @Hellis81 not sure that would workā¦ the fan might not be strong enough. I am exploring other avenues, and will advise if anything works. Thanks again for the help.
Have you solved this problem? Have you looked into how they seal up āclean roomsā. ON new homes which are built to very tight standards they attach a fake door with a large fan to measure leakage for the whole house. The house is caulked several times during construction. All the doors and windows are brand new. If you really need this tightness, try fist to get seal it up and measure the drop. āondrasā idea seems a good approach but unless youāre building new I can only wish you luck.
I havenāt had time unfortunately, so the answer is not.
To clarify, my requirements have changed a little, and instead of reading the pressure of the room, I am going to investigate measuring the āpressureā inside duct feeding the air into the room. I figure I should be able to measure the pressure with a sensor connected to one of these.
Hi there. Iāve looked at various sensors, and I am not sure about placing the entire sensor inside the ducting.
But I figure I could always just test a sensor in the room and see if the sensor is sensitive enough to register a change in temperature when the fan is running?
Might be worth a go, especially if the BME680 is cheap on Aliexpress. Thanks for the tip.
