Potentiometer problem on Arduino

[derekronquillo]

Hi, i'm having a problem with Potentiometer on Arduino. my problem is the Potentiometer values is running continuously which is why my arduino is running slow. what i meant is on "running continuously" is that it reads the value of the potentiometer continuously and it's not stopping. it is supposed to be like: when i move the potentiometer then i should get the value and if i didn't touched or moved the potentiometer it should not print any values on the serial monitor. i'm using a slide potentiometer, Thanks in advance!

[groundFungus]

Please post the test code.

Please read the forum guidelines to see how to properly post code and some information on making a good post.

Use the IDE autoformat tool (ctrl-t or Tools, Auto format) before posting code in a code block.

Please post a schematic. Written descriptions are always more ambiguous than a drawing. Hand drawn, photographed and posted is fine. Include all pin names/numbers, components, their part numbers and/or values and power supplies.

[madmark2150]

You need to only print when the value changes. Retain the last value and only update when different, then save new value for next pass.

[derekronquillo]

yeah, how should i do that?
could you give me a code?

[madmark2150]

What you got so far? Please post using the < code > button!

[derekronquillo]

int sensorValue = 0;

void setup()
{
  pinMode(A0, INPUT);
  Serial.begin(9600);
}

void loop()
{
  // read the input on analog pin 0:
  sensorValue = analogRead(A0);
  // print out the value you read:
  Serial.println(sensorValue);
  delay(10); // Delay a little bit to improve simulation performance
}

[derekronquillo]

@derekronquillo

int sensorValue = 0;
int oldSensorValue = 0;

void setup()
{
  Serial.begin(9600);
}

void loop()
{
  // read the input on analog pin 0:
  sensorValue = analogRead(A0);
   //   Compare to the last value read. 
  if(sensorValue != oldSensorValue){
       // print out the value you read:
       Serial.println(sensorValue);
       oldSensorValue = sensorValue;  // Save the value for comparison
       delay(10); // Delay a little bit to improve simulation performance
}

Dude, Thank you so much for your help. i've been having this issue for a couple of years now haha Thank you so much!!!

[madmark2150]

int sensorValue = 0;
int oldSensorValue = 0;  // last reading

void setup()
{
 // pinMode(A0, INPUT); // not needed as A0 defauts to input
  Serial.begin(115200); // set ide to match!
}

void loop()
{
  // read the input on analog pin 0:
  sensorValue = analogRead(A0);
if (oldSensorValue != sensorValue)
{
  // print out the value you read:
  Serial.println(sensorValue);
oldSensorValue = sensorValue;
}
// no longer needed  delay(10); // Delay a little bit to improve simulation performance
}

[alto777]

@derekronquillo

i've been having this issue for a couple of years

You can also cut it down more, if you need, by only printing if it is enough different, you choose how much is enough:

if (abs(oldSensorValue - sensorValue) > 20) {

"if the new value is more than 20 units away from the old value…"

It's a common pattern and uses the abs() function. Absolute value like from maths class.

Fancier yet: print the new value if it is different enough. Print no matter what every 700 milliseconds (or however often).

Just an idea.

a7

[jim-p]

@derekronquillo Don't forget to mark you topic as solved

[Wawa]

What are you doing with that value.
If it's used to write to a PWM pin (0-255), then use this code.
It has hysteresis, so it doesn't jump.
Leo..

int rawValue, oldValue;
byte potValue;

void setup() {
  Serial.begin(115200);
}

void loop() {
  rawValue = analogRead(A0); // read
  if (abs(rawValue - oldValue) >= 4) { // hysteresis
    oldValue = rawValue; // remember the change
    potValue = oldValue >> 2; // 10-bit to 8-bit
    Serial.println(potValue); // print changes
  }
}