Koepel:
Is that a software low pass filter ? Such a filter works better with 'float' variables, because then no bits will get lost.I suggest to start with the average of a number of samples with analogRead(). For example the average of 10 or 100 analogRead().
Is that an Arduino Nano ? The sensor is ratiometric, that means you have to power it with the 5V pin of the Arduino board. Can you confirm that you have that ? Can you measure the voltage of the 5V pin of the Arduino ?
Are those two 6V pumps for blood pressure meters ? You have them in series to a 12V power supply ? A DC motor does not have a steady current, that means they influence each other when used in series. I don't like that.
When the pump is running, the vibration from the pump travels through the air inside the tubes to the pressure sensor.
Will the tube be longer for the final project ? The longer the tubes, the less air vibration. You could even add a damper chamber.What kind of hardware filter do you use ?
I think that a hardware filter or damper chamber is not needed. Noisy measurements can be eliminated with the average of a number of samples and pump vibrations can be filtered with a moving average. Depending on the number of samples per second and on the window of the moving average, that can be faster than a software low pass filter.
Yes I am using a nano and yes they are blood pump mini air pumps in parallel running on 9 volts. The pressure sensor is getting 5 volts from the nano. The hardware filter is a 3.3k resistor and a 1uf capacitor.