Potnetiometers and analog inputs

Other Hardware Sensors
1

Good morning.

I connected a B10K, 0° to 270° potentiometer to an arduino pro mini, one end of the potentiometer to Vcc (5V) and the other to the ground, the middle terminal to pin A0. When I read the data on pin A0 through a serial monitor, it was not linear at all.
From 0° to 210° it was reading less than 10, up to 250° was less than 100 and suddenly, in the last 20° it goes from 100 to almost 1000, id didn't reach 1023.
Could someone please help me to understand what's going on?
Is it expected? I mean, if I use these data to control a power source it will be linear?

Here is the code:

int Ppot = A0;
int Vpot;
int Pbas = 10;

void setup() {
pinMode(Pbas, OUTPUT);
pinMode(Ppot, OUTPUT);
Serial.begin(9600);

}

void loop() {
Vpot = analogRead(Ppot);
//Vpot = map(Vpot,0,900,0,254);
Serial.println(Vpot);
}

Thank you all, stay health

2

Why have you set your input pin Ppot to OUTPUT mode?

Steve

3

OMG
The only answer is, I'm 60 years old, did that late at night and didn't review all the sketch
Thank you very much

4

I suspect your pot is an "audio pot", they are logarithmic not linear.
If you swap the plus side with the minus side of the pot, not the wiper, I suspect you will see the opposite effect that you have now.

5

potentiometer is linear, what was wrong is the line on code where I declare the analog input as an output, I erased that line and works perfectly

Thank you anyway

6

Thanks for posting the finding. When I read the symptom I jump to a conclusion without fully reading all the information. Hopefully I learned from this too.

7

LaserSteve:
Thanks for posting the finding. When I read the symptom I jump to a conclusion without fully reading all the information. Hopefully I learned from this too.

Log pots are generally type A (Audio taper) so B types as in B10K are (almost) always linear.

Steve

8

Thanks everyone, the most important lesson I learned is to always review the code with clear mind and that there are good people here to help.

Thank you again.