hi every body

I have an arduino project as assignment

If we do your assignment, will we get the credits ?

I'm guessing that this isn't the first time your class has touched either Arduino or microcontrollers, since you don't throw people into a bottomless pool.

There are plenty of tutorials on the web and on these pages.

My suggestion is you do a design based on the information you have (ie the tach and the 0-10v), LCD 16x2 display.

Don't attempt to design the solution/code yet just the blocks required.

You obviously need to translate the 0-10v to 0-5v (or 0-3v3 for some versions) so that's another block.

10v divided by 2mV is 5000 so you already have the maximum number to display.

Once you have all the blocks and the basic design you can then either write the code, or search for code that suits.

Douglas has pointed you to the LCD and there are plenty of others for measuring analogue voltages..

If you get stuck with parts of your code, then feel free to ask for advice, there are lots who can offer advice, but won't do it for you.

Mark

Now

I have 5 block

1) the generator

2) signal conditioning  , i will use 2 resistance each 1k , and take the measurment from el middle

3) tach sensor

4) arduino

5) LCD

I want a help in writing the code , i should take the output and mul by2  , and divide it .002

sarah

sarah

Your step 2 will give you a voltage between 0 and 5 on the middle pin, which is within range of the Arduino.

The tachometer is currently giving 2mV / Rev, and if you divide it by 2 (2x1k resistors as a voltage divider) then its 1mV / Rev, so you don't need to divide then multiply.

Have you actually tried the example Douglas pointed you to?

It has all the connections and as a bonus is already measuring an analog voltage.

I suggest you do the example, get that working then look at modifying it to suit your task.

I always find it useful to understand what I'm trying to achieve before trying to write the code.

That way you can see where you need to go/modify or change.

I'm not sure you have that yet.

Mark

#include <LiquidCrystal.h>
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
int y=0;
int x=0;

void setup()
{
  lcd.begin(16, 2);
pinMode(y,INPUT);
}
void loop()
{
  x=analogRead(y);
  lcd.print("sarah");
lcd.setCursor(0, 1);
x=x/.01;
lcd.print(x);
delay (100);
lcd.clear(); }

  I did it

but i don't understand ur note "

The tachometer is currently giving 2mV / Rev, and if you divide it by 2 (2x1k resistors as a voltage divider) then its 1mV / Rev, so you don't need to divide then multiply.

"

i know that i have to return the last value of the voltage , u mean i just shall mul  by 2 ?

sarah

It seems you have done part of it.

Have you measured the analog voltage that was in the tutorial....?

I know your setup is different to the tutorial as the pin numbers for the lcd are swapped...which is fine.

If you understand the Analog and how it works, you will understand that you get a number between 0 (0volts) and 1023 (5volts).

Arduino - AnalogRead

In your assignment the tachometer gives 0-10v which represents .002 V per Revolution.

When its divided by 2 (with the resistor divider) it now gives 0 - 5v and .001V per Revolution.

You can simulate your tachometer by connecting the top of the resistor divider to the 5v..

You will get half the 5v (2.5v) which equals 2500rpm.

By using a second divider (another 2 resistors) you would get 1250 rpm.

mark

sarah

It seems you have done part of it.

Have you measured the analog voltage that was in the tutorial....?

I know your setup is different to the tutorial as the pin numbers for the lcd are swapped...which is fine.

If you understand the Analog and how it works, you will understand that you get a number between 0 (0volts) and 1023 (5volts).

Arduino - AnalogRead

In your assignment the tachometer gives 0-10v which represents .002 V per Revolution.

When its divided by 2 (with the resistor divider) it now gives 0 - 5v and .001V per Revolution.

You can simulate your tachometer by connecting the top of the resistor divider to the 5v..

You will get half the 5v (2.5v) which equals 2500rpm.

By using a second divider (another 2 resistors) you would get 1250 rpm.

mark

honestly

i can't understand what do u mean  :/

about the the Analog and how it works

if there's any mistakes just tell me , i will try to repair and fix it

thanks a lot 4 ur following my teacher

Full scale output from the tach is 10V = 5000rpm. If you divide this voltage by 2 with resistors now you have 5 V still at 5000 rpm. This 5 V at the A/D is read as 1023 (which is just full scale on the 10 bit A/D). To convert the 1023 reading to 5000 rpm you need to multiply by 4.89. So for this tach, all A/D readings should be multiplied by 4.89 if you use a divide by 2 voltage divider.

now i got it

thank u very much

i found the map function is very useful

#include <LiquidCrystal.h>
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
int y=0;
int x=0;

void setup()
{
  lcd.begin(16, 2);
pinMode(y,INPUT);
}
void loop()
{
  x=analogRead(y);
x = map(x, 0, 1023, 0, 5);
x = x*2 ;

 
  lcd.print("sarah");
lcd.setCursor(0, 1);
x=x/.01 ;
lcd.print(x);
delay (100);
lcd.clear(); }