How to display pressure with 1 increments

mOskit · December 1, 2014, 5:57pm

Hi guys.
I managed to make my own simple program without asking questions but… i get to the stage where i cannot figure out how write this program to display PSI pressure withou xxx.00
Simply saying i only want my display to show->0 1 2 3 instead 0.008 or 1.28 or 4.99 psi.
i have a sensor that is designED for 150psi. 0.5v=0psi 4,5v=150psi.
overaul reason is that i need to display 5 sensors on 16x2 display.

Code below

/*
5 ANALOG PRESSURE SENSORS

*/

// include the library code:
#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);
int sensorValue = 1;
int sensorValue2 = 2;
int val = 0;

void setup() {

Serial.begin(9600);

// LCD type
lcd.begin(16, 2);
// Print a message to the LCD.
lcd.setCursor(4, 0);
lcd.print(“PRESSURE”);
lcd.setCursor(5, 1);
lcd.print(“SENSOR”);
delay(5000);
lcd.clear();
lcd.print(“P1 P2 P5”);
lcd.setCursor(0, 1);
lcd.print("P3 P4 | ");

}
void loop() {
int raw;
float voltage;
float pressure; //pressure in psi

// read the input pin

raw = analogRead(A1);

// Calculate the input voltage
// Using the full input range of 5V.
voltage = (float) raw / 1023.0 * 5.0;

// The pressure is with a linear scale.
// 0.5 V = 0 psi
// 4.5 V = 150 psi
// That is 37.5 psi per voltage.
// At 0.5V the pressure is 0 psi
pressure = 0 + (voltage * 37.5);
lcd.setCursor(2,0);
lcd.print(pressure);
}

jboyton · December 1, 2014, 6:21pm

The syntax for what you want is there.

system · December 1, 2014, 6:34pm

Same way you'd round any number - add a half, and truncate.

mOskit · December 1, 2014, 7:07pm

ok, i`ve read your suggestions and… so far my readout stuck on “1” on p1 and “0” on p3 no matter which way i turn the post (simulating sensor) those values wont change.
i guess i do something wrong

/*
5 ANALOG PRESSURE SENSORS

*/

// include the library code:
#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);
int sensorValue = 1;
int sensorValue2 = 2;
int val = 0;

void setup() {

Serial.begin(9600);

// set up the LCD’s number of columns and rows:
lcd.begin(16, 2);
// Print a message to the LCD.
lcd.setCursor(4, 0);
lcd.print(“PRESSURE”);
lcd.setCursor(5, 1);
lcd.print(“SENSOR”);
delay(500);
lcd.clear();
lcd.print(“P1 P2 P5”);
lcd.setCursor(0, 1);
lcd.print("P3 P4 | ");

}
void loop() {
int raw;
float voltage;
float pressure; //pressure in psi

// read the input pin

raw = analogRead(A1);

// Calculate the input voltage
// Using the full input range of 5V.
voltage = (float) raw / 1023.0 * 5.0;

// The pressure is with a linear scale.
// 0.5 V = 0 psi
// 4.5 V = 150 psi
// That is 37.5 psi per voltage.
// At 0.5V the pressure is 0 psi
pressure = 0 + (voltage * 37.5);
lcd.setCursor(2,0);
lcd.print(0.123456,0);
delay(500);
raw = analogRead(A2);
voltage = (float) raw / 1023* 5.0;
pressure = 0+ (voltage * 37.5);
lcd.setCursor(2,1);
lcd.print(0.123456,0) ;
}

jboyton · December 1, 2014, 7:11pm

Very humorous.

johnwasser · December 1, 2014, 7:24pm

pressure = (((float)analogRead(A0) / 1023.0 * 5.0) - 0.5) * 37.5; 
lcd.setCursor(2,0);
lcd.print(pressure+0.5, 0);  // Print pressure rounded up to the next full PSI with no decimal places

// OR
lcd.print((int)(pressure+0.5));  // Print pressure rounded up to the next full PSI as an integer

jboyton · December 1, 2014, 7:43pm

print(pressure,0) will round so it's not necessary to add 0.5.

mOskit · December 1, 2014, 7:58pm

does work, indeed, but values below 100psi are displayed with xx0 which gives false readoud. i know that this is lets say 40psi but display show 400... once its 990 count stars from 100 and ends on 188

system · December 1, 2014, 8:01pm

but values below 100psi are displayed with xx0 which gives false readoud.

So print a couple of spaces after every value, or get clever with some simple comparisons.

Please remember to use code tags when posting code.

mOskit · December 1, 2014, 8:03pm

Ill try to do my best to suite this forum. Im totally new here

mOskit · December 1, 2014, 8:13pm

AWOL:
So print a couple of spaces after every value, or get clever with some simple comparisons.

Please remember to use code tags when posting code.

Do you mean i should use “<-10”,">-10",">0",">=10" formulas??
Can you please post some example… not necessary related to the post.
Sorry for lack of technical language.

mOskit · December 2, 2014, 8:35pm

Hi.
So i`ve figured out how to print without unnecessary characters.
Can you please give me some advice on how to choose where particular range is displayed.
E.G.
0-9 column 3
10-99 column 3-4
100-150 column 2-3-4

Code:

//Sensor #1

raw = analogRead(A1);
voltage = (float) raw / 1023.0 * 5.0;
pressure = (((float)analogRead(A1) / 1023.0 * 5.0) - 0.5) * 37.5;

if (pressure>-100)
{
lcd.setCursor(4,0);
lcd.write(254);
lcd.setCursor(2,0);
lcd.print(pressure,0);
}
if (pressure<-100)
{
lcd.setCursor(4,0);
lcd.write(254);
lcd.setCursor(3,0);
lcd.print(pressure,0);
}

if (pressure <-10);
{
lcd.setCursor(3,0);
lcd.write(254);
lcd.setCursor(2,0);
lcd.print(pressure,0);
}

if (pressure <0);
{
lcd.setCursor(4,0);
lcd.write(254);
lcd.setCursor(2,0);
lcd.print(pressure,0);
}

i appreciate any help.

system · December 2, 2014, 8:39pm

   if (pressure <-10);

Lose the semicolons; you’ve never seen example code looking like that.

mOskit · December 2, 2014, 8:47pm

Ups did not noticed that at all.
Thanks

mOskit · December 2, 2014, 8:52pm

AWOL did you noticed that without semicolon value 0-9 is displayed with additional 0 and with semicolon without?

system · December 2, 2014, 8:54pm

I didn't run the code or look too closely at it; I just saw semicolons where semicolons don't belong.

system · December 2, 2014, 11:01pm

Why
does
your
code
indent
every
line
in
a
block?

mOskit · December 3, 2014, 8:00pm

PaulS, thankyou for pointing that but u don`t thinks this is what i asked.
Any one??

system · December 3, 2014, 8:02pm

Anyone what?

mOskit · December 3, 2014, 8:13pm

mOskit:
Hi.
So i`ve figured out how to print without unnecessary characters.
Can you please give me some advice on how to choose where particular range is displayed.
E.G.
0-9 column 3
10-99 column 3-4
100-150 column 2-3-4

Code:

//Sensor #1

raw = analogRead(A1);
voltage = (float) raw / 1023.0 * 5.0;
pressure = (((float)analogRead(A1) / 1023.0 * 5.0) - 0.5) * 37.5;

if (pressure>-100)
{
lcd.setCursor(4,0);
lcd.write(254);
lcd.setCursor(2,0);
lcd.print(pressure,0);
}
if (pressure<-100)
{
lcd.setCursor(4,0);
lcd.write(254);
lcd.setCursor(3,0);
lcd.print(pressure,0);
}

if (pressure <-10);
{
lcd.setCursor(3,0);
lcd.write(254);
lcd.setCursor(2,0);
lcd.print(pressure,0);
}

if (pressure <0);
{
lcd.setCursor(4,0);
lcd.write(254);
lcd.setCursor(2,0);
lcd.print(pressure,0);
}

i appreciate any help.