Understanding the resolution of a pressure sensor (MPX5010DP)

Hi,

i have a MPX5010DP data sheetwhich has a resolution of 450mV / kPa. I also use an Arduni Uno or Mega.

I have now seen example calculations on various sites, but do not quite understand them.

I would now like to know what are the smallest values per step that the sensor can output.

So for example the sensor manages to output values in 1Pa steps?

An example calculation and explanation would be optimal.

Greetings
Tommy

Its an analog sensor, it doesn't have a resolution. It has accuracy, sensitivity,
hysteresis/repeatability, tempco, noise, long-term drift. 450mV/kPa is the sensitivity.

Resolution applies when you digitize a signal, so with Arduinos this is going to be a
property of the ADC involved.

The datasheet doesn't give noise or hysteresis information, but usually silicon MEMS pressure sensors are fairly well behaved - the choice of ADC (and voltage reference) are probably limiting factors (although note the absolute accuracy is poor for this device - calibration required)

I'm sorry. I meant the sensitivity. It was a mistranslation.

Yeah I'm using the Arduino and want to get a digital output. So the ADC also has impact on the result.

And then it's still the same question. What is the smalles value per step that the sensor (or the Arduino at the end) can output?

The sensor has a typical output range of 0.2volt to 4,7volt on a 5volt supply.
Or, better said, 4% to 94% of it's supply voltage.

Resolution is therefore 94% - 4% = 90% of the A/D used (10-bit for an Uno).
Or 1024*0.9= ~922 steps of the pressure span of the sensor.
Or 10kPa/922 = ~10.8Pa per A/D step.
More than 10x worse then your 1Pa expectation.
Leo..

1 Like

Crossposting in German section: https://forum.arduino.cc/t/verstandnisproblem-auflosung-bei-drucksensor-mpx5010dp/866836

Internal amplifier and accuracy already explained: https://forum.arduino.cc/t/selection-of-pressure-sensors-for-wind-tunnel/860921. That topic was also crossposted in the German section: https://forum.arduino.cc/t/luftdrucksensor-auswahl-windkanal/860916.

This is the answer I was searching for! Thank you!