How can i measure the deferential pressure in a room using Arduino

Hi guys,

i want to measure the pressure of a room, i want to keep the pressure inside it to 1 bar.

can i do it with Arduino? and what is the name of the sensor?

The title is very confusing...

Differential pressure, as you can see in the name, is the difference in pressure on two separate spots. It can be calculated as:

Total Pressure = differential pressure + static pressure.

For example, it is commonly used in aviation to measure the airspeed due to the change in altitude the static reference pressure will increase.

hamzatay:
i want to measure the pressure of a room, i want to keep the pressure inside it to 1 bar.

How do you wan't to do this?
However, I think you mean this:

My daughter did a project at work using a Sensirion sdp800 over i2c with the Wire library. It's a few years ago, and she can't recall if she had to roll her own code at the register level or if she found another library to care of that.

leandra_reis:
My daughter did a project at work using a Sensirion sdp800 over i2c with the Wire library. It's a few years ago, and she can't recall if she had to roll her own code at the register level or if she found another library to care of that.

The thing is, he/she didn't mean a differential pressure sensor. As I mentioned, a differential pressure sensor measures only the differential pressure. Therefore, you cannot see if your rooms pressure is 1 bar.

ps to #2, she says she found the code, and evidently rolled her own code at the register level.

dyso:
Therefore, you cannot see if your rooms pressure is 1 bar.

Yeah iir her project involved keeping a room at a particular pressure above the one next door, some kind of clean room thing, I can't recall any details.

But @OP Sensirion has lots of sensors, not cheap though, being pro quality, and may involve coding at the register level.

Pitot tube sensors (used for air speed) might be sensitive enough for that.
I think the MPX7002DP is frequently used for that.
Leo…

If you have a tube between the rooms you can detect the flow of air form the higher pressure to the lower pressure .
Use two heated thermistor beads close to one another , heat will be transferred from one to the other by the air flow and you can detect this by the voltage required to maintain a constant resistance .
You can also use a lightweight hinged flap to detect the flow
Honeywell might do some sensors too.

hammy:
Honeywell might do some sensors too.

Yeah the HSC from honeywell is amazing! I did some tests with it in the wind tunnel and after filtering the data it was less than 1 pascal away from the expensive 10000 dollar sensors.

hammy:
If you have a tube between the rooms

If OP has rooms plural, that's something we're inferring from the phrase "deferential [sic] pressure" in the subject line.

leandra_reis:
If OP has rooms plural, that’s something we’re inferring from the phrase “deferential [sic] pressure” in the subject line.

I think it’s pointless to make assumptions. The title and question are very misleading. This is something that the OP need to define properly.

dyso:
The title is very confusing...

Differential pressure, as you can see in the name, is the difference in pressure on two separate spots. It can be calculated as:

Total Pressure = differential pressure + static pressure.

For example, it is commonly used in aviation to measure the airspeed due to the change in altitude the static reference pressure will increase.

How do you wan't to do this?
However, I think you mean this:
https://www.adafruit.com/product/2651

Well, i want keep the pressure for a specific room 1 static bar. I want to know if that possible by using Arduino or not and what the type of that sensor?

To measure the ambient pressure, the link I provided should work fine. How you will increase or decrease the pressure of the room is up to you.

hamzatay:
Well, i want keep the pressure for a specific room 1 static bar.

1 bar absolute pressure, or 1 bar higher than atmospheric?
Both can be measured with an Arduino (sensor depends on your actual needs - such as differential or absolute pressure, precision, reaction speed), which then in turn can send a signal to the air pump to add or remove air from the room to get to the correct pressure.

leandra_reis:
My daughter did a project at work using a Sensirion sdp800 over i2c with the Wire library. It's a few years ago, and she can't recall if she had to roll her own code at the register level or if she found another library to care of that.

Do you a type that handle 1 bar?

hamzatay:
Do you a type that handle 1 bar?

Why don't you look at their website....

Wawa:
Pitot tube sensors (used for air speed) might be sensitive enough for that.
I think the MPX7002DP is frequently used for that.
Leo…

It can handle 2kpa only i want 100kpa at least.

There is a whole range of MPX sensors... and of course there are others out there as well. Do your homework!

hamzatay:
It can handle 2kpa only i want 100kpa at least.

So confusing. I think you messed up big time by not being precise. A differential pressure measures the difference between 2 different pressures. That is why it is used to measure air speed. Again:

P_tot = P_diff + P_static

It is basically the difference between the total pressure that you measure at one point to the reference pressure at the other point. So where is your other point??? Be precise. Research what pressure you want to measure instead of writing, "I want to measure 1 bar". Look at reply #13, answer this question that wvmarle asked. If you can't then tell us about your experiment maybe? I don't believe you will benefit at all with a DP that measures 1 bar differential pressure.

1 Bar = 100kPa = 100'000 N/m² = 0.1N/mm²

Normal atmospheric pressure is right about 1 bar or about 101.235 kPa. In my side of things about 14.5 psia. Now what you seem to want is to bring the pressure in a room about 100 kPa so the differential pressure inside the room is 101 kPa above atmosphere which the atmosphere constantly changes a little day to day. Differential pressure is merely the difference between two pressure levels. You want a positive pressure in a room which is typically done to prevent air infiltration and rooms like this normally use an airlock between inside and outside. Normally to prevent dust and foreign particles from entering a room, such as a type of "clean room".

You can look at the SCX or MPX series of sensors which as mentioned come in a wide variety of ranges. If what you are looking to do is maintain a positive pressure inside a room verse outside atmospheric pressure the number you want of 100 kPa is pretty high. Normally we used 3" to 6" of water which is about 0.746 kPa.

Anyway you can look to the SCX Series from Honeywell. Good differential sensors have temperature compensation so you decide how accurate you want or need. A Google of SCX Pressure Sensor Arduino should get you some projects and code examples. How do you plan to produce the positive pressure? You need to start with calculating the air volume in the room.

Anyway you want a delta pressure gauge with two ports for inside and outside giving you the delta pressure. All you want after that is a basic process control. That what you have in mind?

Ron