# Barometric pressure sensor (BME280) or Differential pressure sensor(MPXV7002DP)

I want to measure pressure inside an open acrylic tube, airflow is provided by a DC fan. Which sensor should I use in order to measure the pressure inside the acrylic tube?

If you want to measure the absolute pressure, use an absolute pressure sensor.

The pressure relative to the surrounding atmospheric pressure is measured with a gage (also gauge) or differential pressure sensor. https://www.first-sensor.com/en/products/pressure-sensors/pressure-sensors-and-transmitters/pressure-types.html

mentablack232: I want to measure pressure inside an open acrylic tube, airflow is provided by a DC fan. Which sensor should I use in order to measure the pressure inside the acrylic tube?

Do you want your reading to forecast the weather? If so use absolute. Do you want your sensor to say something about how well the fan is working? If so you need differential.

You need to figure out what the approximate maximum pressure you will be measuring is in order to know which sensor is suitable for the given pressure range. You wouldn't want a sensor that is rated for much higher pressures than you will be measuring, but you also don't want one that can't read the upper part of your range (and possibly even be damaged by it).

inside an open acrylic tube, airflow is provided by a DC fan

If by "open" you mean that the tube opens to the atmosphere, the pressure inside the tube would be close to the atmospheric pressure.

Unfortunately, it is difficult to measure the pressure of moving fluids or gases due to the Bernoulli effect.

Thank you everyone for your answers! I’ll elaborate more on my set-up. I have a an acrylic tube and inside the tube is a ball one side has a dC fan to output air and the other side is a small cover just to not let the ball escape from the tube when it levitates. My goal is measuring the pressure from below the ball(pressure at the front of the DC fan) and the above the acrylic tube in order to relate it with the Bernoulli equation . So in this application and with regards to your answer is should I use MPXV7002DP? or like just what @jremington said

jremington: Unfortunately, it is difficult to measure the pressure of moving fluids or gases due to the Bernoulli effect.

The will be a difficult experiment to do, but it will be a great learning experience.

Buy the MPXV7002DP sensor and experiment with it. If air moves across the sensor opening, the pressure measured will probably be rather different from your expectations.