Scientific Notation like 1.2*10²

Projects Programming
1

Hello,

I want to calculate Pressure.
As for example:
p=x* y=xy
and as an answer it hast to be displayed on LCD in Scientific Notation like :
1.2*10²
how do I program something like this?

--Gizi

2

While p is less than 1.0 multiply by 10 and decrement the display exponent. While p is higher/same 10.0 divide by 10 and increment the exponent.

3

Do your LCD is able to display superscript font need to print it?

4

The dtostre() function can format the number in scientific notion, but it will be in the form x.xexx you can edit that to replace 'e' with '*', and place the exponent as a superscript if needed, but a simple LCD display generally does not supports superscripts.

5

no idea. Can you tell me how to find out?

6

thx, will try it tomorrow

7

what about 1.2 10^2

consider
Output:

func: 98765.43, p 4, sc 9.88, dec 9, frac 876, 9.876 *10^4
9.876 *10^4

Code:

char buf [80];

char *
func (
    double f,
    int    nDigits, 
    char  *buf)
{
    Serial.print (__func__);
    Serial.print (": ");
    Serial.print (f);

    int   p    = log (f)/log(10);
    float sc   = f / pow(10, p);
    int   dec  = sc;
    int   frac = (sc - dec) * pow(10, nDigits);

    Serial.print (", p ");
    Serial.print (p);

    Serial.print (", sc ");
    Serial.print (sc);

    Serial.print (", dec ");
    Serial.print (dec);

    Serial.print (", frac ");
    Serial.print (frac);

    char fmt [20];
    sprintf (fmt, "%%d.%%0%dd *10^%%d", nDigits);

    sprintf (buf, fmt, dec, frac, p);

    Serial.print (", ");
    Serial.print (buf);

    Serial.println ();

    return buf;
}


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

    double f = 98765.4321;

    Serial.println (func (f, 3, buf));

}

void
loop (void)
{
}
8

xx.xxExx for example 1.00E-06 is a common convention, what is wrong with it?

9

Problem is not every1 understands it, sad but true

10

with programming languages only.

11

Looks gr8, so basicly "f" should be the answer to the formula?
f= x * y;
and it would be then displayed on the display like

12

Worked like a charm!
Thx

13

and calculators

14

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