How to Y axis integers only and no fractions

Projects Programming
1

Arduino Uno. IDE 2.3.4
ReadAnalogVoltage sketch with modification to get Y axis 0-5

Please may I know how to make Y axis the numbers integers only and no fractions? Right now the trace is all over the place, 4.032, 3.001 and all that. All I want is the integers (example, 0, 1, 2, 3, 4, 5 and not 1.001, 2.33 etc.)
Thank you.

I am writing modified this code

/*
  ReadAnalogVoltage
  Center pin of a potentiometer to pin A0, and the outside pins to +5V and ground.
 Dr. G
*/
// the setup routine runs once when you press reset:
void setup() {
  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);
}

// the loop routine runs over and over again forever:
void loop() {
  // read the input on analog pin 0:
  int sensorValue = analogRead(A0);
  // Convert the analog reading (which goes from 0 - 1023) to a voltage (0 - 5V):
  float voltage = sensorValue * (5.0 / 1050.0);
  // print out the value you read:
  Serial.println(voltage);
  delay(200);  // delay in between reads for stability
}
2

Your topic does not indicate a problem with IDE 2.x and hence has been moved to a more suitable location on the forum.

3 
float pi = 3.14;
int value = (int)pi)

Not tested but should print 3.

4

Try:

1 Like
5

Ardunio fractions
Ardunio fractions1063×657 52.2 KB

Thank you. The plotter reads one fractional value, i.e. 3.5, 3.7, 2.5, 2.2 etc. and not 1, 2 3, 4, 5, etc. but I can live with the single fraction. Also, I noticed the jitter I was getting previously is gone. New breadboard, new pot, new Arduino, less electrical noise (yes, our workshops yet have fluorescent bulbs) .

/*
  ReadAnalogVoltage
  Center pin of a potentiometer to pin A0, and the outside pins to +5V and ground.
 modified by yours truly Dr. G
*/
// the setup routine runs once when you press reset:
void setup() {
  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);
}

// the loop routine runs over and over again forever:
void loop() {
  // read the input on analog pin 0:
  int sensorValue = analogRead(A0);
  // Convert the analog reading (which goes from 0 - 1023) to a voltage (0 - 5V):
  float voltage = sensorValue * (5.0 / 1050.0);
  // print out the value of the potentiometer as an interger only:
Serial.println(voltage,0);
  delay(200);  // delay in between reads for stability
}
6

Thank you, and appreciate your patience with a newbie.

7 
/*
  ReadAnalogVoltage
  Center pin of a potentiometer to pin A0, and the outside pins to +5V and ground.
 modified by yours truly Dr. G
*/
// the setup routine runs once when you press reset:
void setup() {
  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);
}

// the loop routine runs over and over again forever:
void loop() {
  // read the input on analog pin 0:
  int sensorValue = analogRead(A0);
  // Convert the analog reading (which goes from 0 - 1023) to a voltage (0 - 5V):
  float voltage = sensorValue * (5.0 / 1050.0);
  // print out the value of the potentiometer as an interger only:

float pi = 3.14;
int value = (int)pi);
Serial.println(voltage,0);

  delay(200);  // delay in between reads for stability
}

C:\Users\Acer_new\Documents\Arduino\AnalogReadSerial_with_pi\AnalogReadSerial_with_pi.ino: In function 'void loop()':
C:\Users\Acer_new\Documents\Arduino\AnalogReadSerial_with_pi\AnalogReadSerial_with_pi.ino:21:20: error: expected ',' or ';' before ')' token
int value = (int)pi);
^

exit status 1

Compilation error: expected ',' or ';' before ')' token

8

Sorry, typo. That last ) should not be there

1 Like
9

That was an example how to truncate a float… not something that you would have in your code…

1 Like
10

Did you intend 1050.0, or 1024.0?

1 Like
11

look this over

Output

 anlg  729, val   3.47, num   3
 anlg  724, val   3.45, num   3
 anlg  715, val   3.40, num   3
 anlg  691, val   3.29, num   3
 anlg  672, val   3.20, num   3
 anlg  657, val   3.13, num   3
 anlg  642, val   3.06, num   3
 anlg  624, val   2.97, num   3
 anlg  606, val   2.89, num   3
 anlg  584, val   2.78, num   3
 anlg  564, val   2.69, num   3
 anlg  552, val   2.63, num   3
 anlg  529, val   2.52, num   3

 anlg  517, val   2.46, num   2
 anlg  497, val   2.37, num   2
 anlg  485, val   2.31, num   2
 anlg  463, val   2.20, num   2
 anlg  451, val   2.15, num   2
 anlg  434, val   2.07, num   2
 anlg  420, val   2.00, num   2
 anlg  394, val   1.88, num   2
 anlg  389, val   1.85, num   2
 anlg  361, val   1.72, num   2
 anlg  361, val   1.72, num   2
 anlg  331, val   1.58, num   2
 anlg  328, val   1.56, num   2

 anlg  301, val   1.43, num   1
 anlg  280, val   1.33, num   1
 anlg  271, val   1.29, num   1
 anlg  241, val   1.15, num   1
 anlg  240, val   1.14, num   1
 anlg  208, val   0.99, num   1
 anlg  200, val   0.95, num   1
 anlg  176, val   0.84, num   1
 anlg  142, val   0.68, num   1
 anlg  139, val   0.66, num   1
 anlg  106, val   0.50, num   1

 anlg   86, val   0.41, num   0
 anlg   73, val   0.35, num   0
 anlg   42, val   0.20, num   0
 anlg   42, val   0.20, num   0
 anlg   41, val   0.20, num   0
 anlg   41, val   0.20, num   0

char s [90];
char t [20];

void
loop (void)
{
    int   anlg = analogRead (A0);
    float val  = anlg * 5.0 / 1050.0;   // scale
    int   num  = val  + 0.5;            // integerize, round up

    dtostrf (val, 6, 2, t);         // sprintf doesn't support %f
    sprintf (s, " anlg %4d, val %s, num %3d", anlg, t, num);
    Serial.println (s );

    delay (1000);
}

void
setup (void)
{
    Serial.begin (9600);
}
1 Like
12

With a println(voltage,0), The jitter isn't gone. It is just discarded by the reporting process.

1 Like
13

Thanks, David. I did 1050.0 while playing with the numbers. I was measuring the actual voltage (with a DMM) and 1050.0 was the most accurate. Yes, 1024.0 is the "official" denominator. My code writing would not pass conscientious and meticulous
examination.

14

DaveXFaraday, you are good. Thank you.

15

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