Temperature dependent time control

[sebbl86]

Dear all,

I want to program my Arduino to start a fan for a defined period of time if the enviroment Temperature is higher than a defined Tempature. So far so easy. But I would not like to use a delay, as I also want the Arduino to update other incoming data and the LCD in the same time the fan is running. So I have to work with millis() (and yes, I watched blinkwithoutdelay 1000 times ) but Im still lost. Problem is, that the if funtion (if (temp1>Tsoll) kills all following attempts of time controlling. The fan should stay on even if temp1 falls below the defined value again. Need help.
Best regards and Thanks.

[Idahowalker]

Please follow the advice given in the link below when posting code, in particular the section entitled 'Posting code and common code problems'

Use code tags (the </> icon above the compose window) to make it easier to read and copy for examination

How to get the best out of this forum

See also FAQ - Arduino Forum for general rules on forum behavior and etiquette. Hello, Welcome to the Arduino Forum. This guide explains how to get the best out of this forum. Please read and follow the instructions below. Being new here you might think this is having rules for the sake of rules, but that is not the case. If you don’t follow the guidelines all that happens is there is a long exchange of posts while we try to get you to tell us what we need in order to help you, which is frus…

Use the IDE autoformat tool (ctrl-t or Tools, Auto format) before posting code in code tags.

Include the entire error message. It is easy to do. There is a button (lower right of the IDE window) called "copy error message". Copy the error and paste into a post in code tags. Paraphrasing the error message leaves out important information.

Post a schematic.

Post an image of your project.

Which Micro Controller are you using?

Is this simulator code?

Please describe the problem better then you just did.

Info about multi things

Demonstration code for several things at the same time

NOTE for newcomers. The demo is entirely contained in this Post and Reply #1. There is no need to read further unless you are interested. ...added 25Sep2014 There have been a few occasions recently where newcomers seemed to have difficulty applying the "blink without delay" and "state" concepts to a sketch that is intended to manage a number of concurrent actions. Its very time consuming to respond with suitable code examples - particularly as every case is a little different. I have prepared…

[johnwasser]

@sebbl86

Problem is, that the if funtion (if (temp1>Tsoll) kills all following attempts of time controlling.

Move the timing out of the 'if'. Before you check the temperature, check if the fan is on and, if it is, check if it has been on for the required amount of time.

[gcjr]

@sebbl86

I watched blinkwithoutdelay 1000 times ) but Im still lost. Problem is, that the if funtion (if (temp1>Tsoll) kills all following attempts of time controlling. The fan should stay on even if temp1 falls below the defined value again.

consider

const byte PinInp = A0;
const byte PinLed = LED_BUILTIN;

const int  Thresh = 500;

enum { Off = HIGH, On = LOW };

unsigned long msecPeriod = 2000;
unsigned long msecLst;
unsigned long msec;

byte pinState;
bool run;

// -----------------------------------------------------------------------------
void
loop (void)
{
    msec = millis ();

    if (run && (msec - msecLst) >= msecPeriod)  {
        run = false;
        digitalWrite (PinLed, Off);
    }

    int val = analogRead (PinInp);
    if (Thresh <= val)  {
        run = true;
        msecLst = msec;
        digitalWrite (PinLed, On);
    }

    Serial.println (val);
}

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

    pinMode (PinInp, INPUT_PULLUP);
    pinState = analogRead (PinInp);

    pinMode (PinLed, OUTPUT);
    digitalWrite (PinLed, Off);
}

[sebbl86]

Thank you so much. that´s it! directly proofed it with lowering Thresh to 200 to test it with a simple poti. Nice!