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I have an arduino uno with two sensors. Voltage and current sensors. I need to get the average value of voltage and current each time the data is received. But i don't know how to add up the current and previous values and divide it to how many values that it has received.

Can someone help me, please? I need it for my project

This is the code i have made

void setup(){
Serial.begin(9600);
}
void loop(){
    int n=5;
    float sum=0;
    float ave=0;
    for(int x=0;x<n;x++){
        float volt=analogRead(A0);
        float voltage = map(volt,0,1023,0,2500);
        voltage/=100;
        Serial.print("Voltage: ");
        Serial.print(voltage,2);
       sum=sum+voltage;
       }
ave=sum/n;
Serial.print("Average: ");
Serial.print(average,2);
delay(3000);
}

But this only takes the average of 5 datas. I want to get the average of all data received.

Improve this question
6
  • 1
    Cheat: github.com/MajenkoLibraries/Average
    – Majenko
    Dec 11, 2019 at 16:23
  • it's actually communicative: (1/3 + 2/3 + 3/3) == (1+2+3)/3
    – dandavis
    Dec 11, 2019 at 18:38
  • @Majenko does your library offer cumulative average, running average, exponential average, or any/all of those?
    – Duncan C
    Dec 11, 2019 at 20:16
  • 1
    To the OP, do you want a cumulative average? As mentioned in the comments on DataFiddler's answer, with a very large number of samples the average will change so slowly that it will be hard to detect a change. (e.g. After a million samples have been averaged, if the input value suddenly change to 0, it will take 100,000 new samples, all at 0, for the average value to change by 10%)
    – Duncan C
    Dec 11, 2019 at 20:24
  • You might want to use an exponential value or other rolling average instead.
    – Duncan C
    Dec 11, 2019 at 20:24

1 Answer 1

Reset to default
3 
void setup(){
Serial.begin(9600);
}
void loop(){
    static unsigned long count=0;
    static float sum=0;
    float ave=0;
    int volt=analogRead(A0);
    float voltage = map(volt,0,1023,0,2500) / 100.0;
    Serial.print("Voltage: ");
    Serial.print(voltage,2);
    sum=sum+voltage;
    count++;
    ave=sum/count;
    Serial.print("  Average: ");
    Serial.println(ave,2);
    delay(3000);
}

This runs quite a while. The average is restarted only with a Reset of your arduino.

Alternatively, you might want to learn about a moving average (aka low pass filter)

Improve this answer
7
  • You println an unknown variable average. You declared ave. You should also mention that with this method the algorithm can only run some time until float overflows. A saver way would be A(1) = x(1); A(n+1) = A(n) * (n/(n+1)) + x(n+1)/(n+1). "A(n) = avarage in the n-th iteration; x(n) the n-th sensor value."
    – Peter Paul Kiefer
    Dec 11, 2019 at 17:27
  • ave fixed. It will overflow after 400 years of uninterrupted operation, thanks to delay(3000);
    – DataFiddler
    Dec 11, 2019 at 18:11
  • This code receives equal value or output for voltage and average of it. Maybe it doesn't count the previous datas it received
    – Rica Jacutina
    Dec 11, 2019 at 18:14
  • Did you observe the static keyword of sum? Eventually you add more Serial.println to check sum and count as well for debugging?
    – DataFiddler
    Dec 11, 2019 at 18:20
  • Oh. I got it! Thank you so much. I just put a wrong variable on the serialprint for average. 😂
    – Rica Jacutina
    Dec 11, 2019 at 18:26

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