begginer - more than one analog sensor

hi

i am a begginer i dont know much of electrical stuff. i am connecting two analog sensors to the arduino. One is a pressure sensor and the second a potenciometer, they are both from an old icube.

i noticed that when i raise the potenciomenter (analog pin 5) the pressure sensor (analog pin 2) reports values ranging 0 to ~0.16 increasing together as the potenciometer goes up. It is like some kind of residual noise comming from pin 5 that goes into pin 0.

the power cables of both sensors go together to 5v inlet of the arduino and the ground cables go to ground pin, each of the data cable goes to its separate analog pin.

I am using arduino from Pure Data using latest Firmata, so i am just filtering out any value smaller than 0.16 comming from analog pin 0.

is there anything I am doing wrong? or is this normal?

what if i wanted to have more analog sensors (say 4) and also few digital ones (say 3)? is there a basic tutorial of how to deal with complex settings like this?

thanks!

-- edit --- so in fact when the potenciometer reports 1 the pressure sensor reports values jumping randomly between 0.1 and 0.2

the pressure sensor reports values jumping randomly between 0.1 and 0.2

You are showing a floating point result. What is the range and mapping you are using. The analog input for a 0-5vdc signal is 0-1023 counts, an int variable. To better understand how much variation .1 to .2 is we need to see how you scale this value and what the actual analog voltage range you are using.

Lefty

Can you say how you are wiring these potentiometers and pressure sensors? Do you know the value of the potentiometer, it could be that it is too high and thus allowing charge leakage to occur between the inputs. The analogue inputs are recommended to be driven by a 10K or lower impedance source.

mmm... i am not sure i understand. I get values ranging 0 to 1 from both sensors, being 0 no input and 1 full input in the sensor. Does this answer your question? sorry if i did not get it...

when i run only one sensor they work fine. this only happens when both are connected and only with the pressure sensor. I mean the potenciometer does not get any weird data fluctuation when i press the pressure sensor.

mmm... i am not sure i understand. I get values ranging 0 to 1 from both sensors, being 0 no input and 1 full input in the sensor. Does this answer your question? sorry if i did not get it...

No, and I guess you would have to post your Arduino code for us to figure out how you are scaling the analog input value. Also without knowing what voltage range your sensors are sending to the Arduino analog input pin we would still have an incomplete picture of the scaling/resolution question.

Lefty