Timer problem

Projects Programming
1

Hello, I want to stop relay after 30 seconds, but I couldnt make it, I dont want to use delay(); function because other functions of my code must work. I tried something below, but not working,

unsigned long oldtime=0;
unsigned long newtime;

void relaymode()
 {
   relaymod = '1';
   digitalWrite(relay, LOW);
   Serial.println("relay opened");
   
   newtime = millis(); 
   if(relaymod == '1'){  
     if(newtime-oldtime > 30000){      
        digitalWrite(relay, HIGH);
        Serial.println("relay closed");          
     }
   relaymod = '0';
   oldtime = newtime;
     
   }
 }
2

(1) I do not see a setup() function.
(2) I do not see a loop() function.
(3) I do not see a declaration for the variable relaymod.
(4) I cannot see how function relaymode() is called.
(5) Isn't relaymod always set to '1' when the if statement is executed?
(6) If relaymode() is called more than once every 30 seconds (probably, but I cannot be sure) then newtime-oldtime will always be less than 30000.

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3

my sketch is so big and complicated, I cannot share it here. I need a code only will stop when work after 30 seconds. I have a relay, I want only stop my relay after 30 seconds later from open. if you have a solution you can write it here please, if you have not, stop writing any fool things..

4

I was going to give an example until I saw:
"stop writing any fool things"

Good luck.

.

5

LarryD I didnt say something to you and all people in this forum, But somebody in this forum what they want to make I didnt understand. They only write foolish things, rebuke and inversion.

6

Aleyna:
my sketch is so big and complicated, I cannot share it here.

And there's your first problem. You have written a big, complicated sketch when you don't know how to turn a relay on for 30 seconds without delay().

Your function always opens the relay every time it is called. Pull out the first bit - the bit that opens the relay - into its own function. You call that when the relay needs to become open, and you call the other function every loop() to check if it's time to close it again.

7

'relaymod' is always '1' and that keeps reset your 'oldtime' with 'newtime'.

check this code. I didn't executed it.

unsigned long oldtime=0;
unsigned long newtime;
int relayButton=5;
int relayModule=4;

void setup() {
  pinMode(relayModule, OUTPUT);
  pinMode(relayButton, INPUT);
}

void loop() {
  if(digitalRead(relayButton)==HIGH){
    digitalWrite(relayModule, HIGH);
    Serial.println("relay opened");
  }
  relaymode();
}

void relaymode(){
   char relaymod = '1';
   newtime = millis(); 
   if(relaymod == '1'){
      if(newtime-oldtime > 30000){
        digitalWrite(relayModule, LOW);
        Serial.println("relay closed");
        relaymod = '0';
        oldtime = newtime;
     }
  }
}
8

thanks all of you, I will try and response from here :slight_smile: