How to change my incriment value from 1 to a decimal place

Hi all

Ive got a state change detection sketch going on with my arduino uno. It works well and counts each time I close the contacts, and prints it in the serial.

But I now want it to count in 0.2 incriments, but I am stumped on how to do this, is there any way I can define the increment value to something different from 1??

thanks

Hello,

Use a float instead of an int.

Or, use an int, add 2, and divide by 10 only when needed, because it’s more efficient to use int rather than floats.

Without posting your sketch all I can say is:

`````` x += 0.2
``````

Post the code that you are using.

What you want sounds easy. A float variable, let's call it floatVariable then, at it's most explicit

``````floatVariable = floatVariable + 0.2;
``````
``````float myval;

void loop() {
if (...) {
myval += 0.2;
}
}
``````

/* State change detection (edge detection)

Often, you don't need to know the state of a digital input all the time, but you just need to know when the input changes from one state to another. For example, you want to know when a button goes from OFF to ON. This is called state change detection, or edge detection.

This example shows how to detect when a button or button changes from off to on and on to off.

The circuit: * pushbutton attached to pin 2 from +5V * 10K resistor attached to pin 2 from ground * LED attached from pin 13 to ground (or use the built-in LED on most Arduino boards)

created 27 Sep 2005 modified 30 Aug 2011 by Tom Igoe

This example code is in the public domain.

http://arduino.cc/en/Tutorial/ButtonStateChange

*/

// this constant won't change: const int buttonPin = 4; // the pin that the pushbutton is attached to const int ledPin = 13; // the pin that the LED is attached to

// Variables will change: int buttonPushCounter = 0; // counter for the number of button presses int buttonState = 0; // current state of the button int lastButtonState = 0; // previous state of the button

void setup() { // initialize the button pin as a input: pinMode(buttonPin, INPUT); // initialize the LED as an output: pinMode(ledPin, OUTPUT); // initialize serial communication: Serial.begin(9600); }

void loop() { // read the pushbutton input pin: buttonState = digitalRead(buttonPin);

// compare the buttonState to its previous state if (buttonState != lastButtonState) { // if the state has changed, increment the counter if (buttonState == HIGH) { // if the current state is HIGH then the button // wend from off to on: buttonPushCounter++; Serial.print("Rainfall: "); Serial.print(buttonPushCounter); Serial.println("mm"); } else { // if the current state is LOW then the button // wend from on to off: } // Delay a little bit to avoid bouncing delay(50); } // save the current state as the last state, //for next time through the loop lastButtonState = buttonState;

// turns on the LED every four button pushes by // checking the modulo of the button push counter. // the modulo function gives you the remainder of // the division of two numbers: if (buttonPushCounter % 4 == 0) { digitalWrite(ledPin, HIGH); } else { digitalWrite(ledPin, LOW); }

}

``````      buttonPushCounter++;
``````

to

``````      buttonPushCounter += 0.2;
``````

For the sake of sanity I suggest that you change the name of the variable too !

It is not a good idea to use a float as an index in a for loop because of rounding errors. It is possible to add 1.8 and 0.2 and get a number greater than or less than 2.0!

It is much better to do as suggested in post #1 and use an int index and divide when you need the float value.

great I'll give both of them a try. Thanks a lot!

Why do you want 0.2 ?

What are you trying to count?

Make your integer variable ten times bigger then increment by 2