Delay is not working for applied filter on serial analog data sample

[vikas0845]

int pot = A0;
int value;
float v[4]={0.0};

void setup() {
// put your setup code here, to run once:
Serial.begin(9600);
pinMode(pot,INPUT);

}

void loop() {
// put your main code here, to run repeatedly:

value = analogRead(pot);
float x = float(value)*5/1024;

v[0] = v[1];
v[1] = v[2];
v[2] = v[3];
v[3] = v[4];
v[4] = (5.410813636231793788e-1 * x)
+ (-0.49297369305844135345 * v[0])
+ (0.10136107908629476970 * v[1])
+ (0.59665868765467522383 * v[2])
+ (0.45077979658470224145 * v[3]);

float D = v[4]-v[3];
delay(100);
Serial.println(x);
Serial.print(" ");
Serial.print(v[4]);
Serial.print(" ");
Serial.println(D);
}

// I used this code to filter the signal but after adding delay it is not doing serial plotting or serial monitoring. Please give your valuable suggestions.

[UKHeliBob]

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[red_car]

@vikas0845

float v[4]={0.0};

@vikas0845

v[4] = (5.410813636231793788e-1 * x)

• (-0.49297369305844135345 * v[0])
• (0.10136107908629476970 * v[1])
• (0.59665868765467522383 * v[2])
• (0.45077979658470224145 * v[3]);

@vikas0845

float D = v[4]-v[3];

You have defined an array with 4 values. The indices of those values is 0,1,2, and 3.

v[4] is out of range.

The program is crashing and constantly restarting. Put some more print statements in setup to see this.

[red_car]

Also.. floats have about 6-7 digits of precision.

@vikas0845

-0.49297369305844135345

You're dreaming using values like this.

[vikas0845]

Now, I have corrected it and wrote: float v[3] = {0.0};

[UKHeliBob]

Now you have an array that can hold only 3 values with index values 0, 1 and 2

How are you accessing the array ?

[red_car]

@vikas0845

I have corrected it and wrote: float v[3]

So you've defined an even smaller array ???

[vikas0845]

I think by v[3] = {0.0} will initialize v[0], v[1], v[2], v[3] as zero.

[UKHeliBob]

Then you are wrong. It will allocate space to 3 array elements numbered 0, 1 and 2 and initialise them to zero

[octopirate]

@vikas0845

I think..

Better to read the man page

[paulpaulson]

or take a view here to get some ideas:

FIR filter - Arduino Reference

[red_car]

@vikas0845

I think by v[3]

The point is this array holds 3 (THREE) values.

In your code you are trying to access 5 (FIVE) values.

Computer will say NO to this.

[UKHeliBob]

@red_car

Computer will say NO to this.

If only it did !