MPX570AP ardunio

Using Arduino Programming Questions
1

Hi ,

I am new in ardunio forum.. thanks for everything..

I have a mpx5700ap sensor. ı want to mesaure system pressure by using mpx5700ap.

in device datasheet , transfer function is

Vout = VS*(0.0012858*P+0.04) ± Error
VS = 5.0 Vdc

my code is ;

int raw = analogRead(A0);
float voltage= raw0.0048828125; // 5/2^10 adc
float pressure= (((float)((float)voltage-50.04)/(5*0.0012858))); // kpa

and data sheet ;

http://www.nxp.com/assets/documents/data/en/data-sheets/MPX5700.pdf

now, mpx5700ap sensor's port is free but output kpa is 95 according to my code and output voltage 0.8 , why ?

1 atm to kpa ; 101 , but i am reading 95... where is 6 kpa ? :frowning:

thanks everyone..

2

now, mpx5700ap sensor's port is free

What does that mean? Do you now have the sensor connected to the Arduino?

If not, you can not expect any particular return value from analogRead().