I want to turn on a led just once with a selector switch

Projects Programming
1

Good day ! I have a selector switch ( interlock ) with which I want to select the on-time of a LED which turns on when you press the start button and it turns off when the time is over or when i put the selector in off position. Where the first switch position is OFF and the following four positions are different times.

The problem is that when I select OFF should sound a warning buzzer for 1 second (to indicate that the time was interrupted ) likewise should sound for 1 second when the time is over (to indicate that the cycle ended ). But I tried to do with the Function "first time" but the led only turns on just it once , I tried with a delay but it repeats while the selector is in OFF. I implemented my code with switch statement function as follows :

const int min = 0;     
const int max = 1023; 
const int led=13;
const int start=10;
int ledState = LOW;                  
long OnTime = 5000;                     
unsigned long previousMillis = 0; 
int buzzer=3;
 
void setup() {
  pinMode (buzzer, OUTPUT);
  pinMode (led, OUTPUT);

  Serial.begin(9600); }
void loop() {
 
int sensorReading = analogRead(A0);
int range = map(sensorReading, min, max, 0, 7);
unsigned long currentMillis = millis();
switch (range) {
    
case 0:   //Potentiometer turned between 0-25%
   ledState=LOW;
//Here the led should turns on just once and only for a second

   Serial.println("OFF");
    break;
 
 
case 1:    //Potentiometer turned upto 26-50% 
  if((ledState == HIGH) && (currentMillis - previousMillis >= OnTime))  {
    ledState = LOW;  // Turn it off
    previousMillis = currentMillis;  
    digitalWrite(led, ledState); 
  }
  else if ((ledState == LOW) && digitalRead(start)== HIGH)
  {
    ledState = HIGH;  
    previousMillis = currentMillis;   
    digitalWrite(led, ledState);	 
  }
   Serial.println("TIEMPO 1");
   break;
 
case 2:     //Potentiometer turned upto 51-75%
   if((ledState == HIGH) && (currentMillis - previousMillis >= (OnTime + 2000)))  {
    ledState = LOW;  // Turn it off
    previousMillis = currentMillis;  
    digitalWrite(led, ledState);  
  }
  else if ((ledState == LOW) && digitalRead(start)== HIGH)
  {
    ledState = HIGH;  
    previousMillis = currentMillis;   
    digitalWrite(led, ledState);	 
  }
 Serial.println("TIEMPO 2");
 break;
 
case 3:   //Potentiometer turned upto 76-100%
  if((ledState == HIGH) && (currentMillis - previousMillis >= (OnTime + 4000)))
  {
    ledState = LOW;  
    previousMillis = currentMillis;  
    digitalWrite(led, ledState);  
  }
  else if ((ledState == LOW) && digitalRead(start)== HIGH)
  {
    ledState = HIGH;  
    previousMillis = currentMillis;  
    digitalWrite(led, ledState);	  
  }
    Serial.println("TIEMPO 3");
    break;
   
case 4:   //Potentiometer turned upto 76-100%
   if((ledState == HIGH) && (currentMillis - previousMillis >= (OnTime + 6000)))
  {
    ledState = LOW;  
    previousMillis = currentMillis;  
    digitalWrite(led, ledState);  
  }
  else if ((ledState == LOW) && digitalRead(start)== HIGH)
  {
    ledState = HIGH;  
    previousMillis = currentMillis;  
    digitalWrite(led, ledState);	  
  }
  Serial.println("TIEMPO 4");
   break;
   
   case 5:   //Potentiometer turned upto 76-100%
   if((ledState == HIGH) && (currentMillis - previousMillis >= (OnTime + 6000)))
  {
    ledState = LOW;  
    previousMillis = currentMillis;  
    digitalWrite(led, ledState);  
  }
  else if ((ledState == LOW) && digitalRead(start)== HIGH)
  {
    ledState = HIGH;  
    previousMillis = currentMillis;  
    digitalWrite(led, ledState);	  
  }
  Serial.println("TIEMPO 4");
   break;
   
   case 6:   //Potentiometer turned upto 76-100%
   if((ledState == HIGH) && (currentMillis - previousMillis >= (OnTime + 6000)))
  {
    ledState = LOW;  
    previousMillis = currentMillis;  
    digitalWrite(led, ledState);  
  }
  else if ((ledState == LOW) && digitalRead(start)== HIGH)
  {
    ledState = HIGH;  
    previousMillis = currentMillis;  
    digitalWrite(led, ledState);	  
  }
  Serial.println("TIEMPO 4");
   break;
   
   case 7:   //Potentiometer turned upto 76-100%
   if((ledState == HIGH) && (currentMillis - previousMillis >= (OnTime + 6000)))
  {
    ledState = LOW;  
    previousMillis = currentMillis;  
    digitalWrite(led, ledState);  
  }
  else if ((ledState == LOW) && digitalRead(start)== HIGH)
  {
    ledState = HIGH;  
    previousMillis = currentMillis;  
    digitalWrite(led, ledState);	  
  }
  Serial.println("TIEMPO 4");
   break;
  }
   digitalWrite(led, ledState); 
   delay(100);        
 }

I appreciate your help!

2

Maybe something along these lines:

 int buzzer_on_time = 0;
 void handle_buzzer()
 {
   if( buzzer_on_time > 0 )
   {
    // Sound buzzer here ... 
   }
   buzzer_on_time -= millis();
 }

Call handle_buzzer() at the bottom of your loop(), then whenever you want to sound the buzzer, just set buzzer_on_time to however long you want it on for.

3

It sounds to me like you want two possible actions to happen when the case is 0. Either the process starts (which you already have) or the process terminates - which needs extra code to test the state of the process - whether it is already running or is currently stopped.

...R

4

Tammytam i tried something like this, but it runs just once. I need buzzer sounds 1 second each led turns off. But i think i did it wrong, i have some questions i used correctly the void handle_buzzer()? And the if condition is inside my case 0? I´m a begginer in this. :confused: Thank´s!

const int min = 0;     
const int max = 1023; 
const int led=13;
const int start=10;
int ledState = LOW; 
int buzzerState=LOW;
long OnTime = 5000;                     
unsigned long previousMillis = 0; 
int buzzer=3;
int buzzer_on_time = 0;    //NEW LINE
 
void setup() {
  void handle_buzzer();   //NEW LINE
  pinMode (buzzer, OUTPUT);
  pinMode (led, OUTPUT);
  Serial.begin(9600); 
  }
void loop() {
 
int sensorReading = analogRead(A0);
int range = map(sensorReading, min, max, 0, 7);
unsigned long currentMillis = millis();
switch (range) {
  
case 0:  
   ledState=LOW;   //Here the led should turns on just once and only for a second

   Serial.println("OFF");
    break;
5

No thats not quite right. Also, it won't jsut work on its own without detecting a change in range. This is what your after. (Havent checked the code, I've just placed the new parts in the correct places:

const int min = 0;     
const int max = 1023; 
const int led=13;
const int start=10;
int ledState = LOW;                  
long OnTime = 5000;                     
unsigned long previousMillis = 0; 
int buzzer=3;
int buzzer_on_time = 0;
int last_range = -1;

void handle_buzzer()
{
 if( buzzer_on_time > 0 )
 {
 // Sound buzzer here ... 
 }
 buzzer_on_time -= millis();
}

void setup() 
{
 pinMode (buzzer, OUTPUT);
 pinMode (led, OUTPUT);
 Serial.begin(9600); 
}

void loop() 
{
 int sensorReading = analogRead(A0);
 int range = map(sensorReading, min, max, 0, 7);
 unsigned long currentMillis = millis();
 switch (range) 
 {
 case 0:   //Potentiometer turned between 0-25%
 ledState=LOW;
 //Here the led should turns on just once and only for a second
 Serial.println("OFF");

 if( last_range != range )
 buzzer_on_time = 1000;

 break;

 case 1:    //Potentiometer turned upto 26-50% 
 if((ledState == HIGH) && (currentMillis - previousMillis >= OnTime))  
 {
 ledState = LOW;  // Turn it off
 previousMillis = currentMillis;  
 digitalWrite(led, ledState); 
 }
 else if ((ledState == LOW) && digitalRead(start)== HIGH)
 {
 ledState = HIGH;  
 previousMillis = currentMillis;   
 digitalWrite(led, ledState); 
 }
 Serial.println("TIEMPO 1");
 break;

 case 2:     //Potentiometer turned upto 51-75%
 if((ledState == HIGH) && (currentMillis - previousMillis >= (OnTime + 2000)))  
 {
 ledState = LOW;  // Turn it off
 previousMillis = currentMillis;  
 digitalWrite(led, ledState);  
 }
 else if ((ledState == LOW) && digitalRead(start)== HIGH)
 {
 ledState = HIGH;  
 previousMillis = currentMillis;   
 digitalWrite(led, ledState); 
 }
 Serial.println("TIEMPO 2");
 break;
 
 case 3:   //Potentiometer turned upto 76-100%
 if((ledState == HIGH) && (currentMillis - previousMillis >= (OnTime + 4000)))
 {
 ledState = LOW;  
 previousMillis = currentMillis;  
 digitalWrite(led, ledState);  
 }
 else if ((ledState == LOW) && digitalRead(start)== HIGH)
 {
 ledState = HIGH;  
 previousMillis = currentMillis;  
 digitalWrite(led, ledState);  
 }
 Serial.println("TIEMPO 3");
 break;
   
 case 4:   //Potentiometer turned upto 76-100%
 if((ledState == HIGH) && (currentMillis - previousMillis >= (OnTime + 6000)))
 {
 ledState = LOW;  
 previousMillis = currentMillis;  
 digitalWrite(led, ledState);  
 }
 else if ((ledState == LOW) && digitalRead(start)== HIGH)
 {
 ledState = HIGH;  
 previousMillis = currentMillis;  
 digitalWrite(led, ledState);  
 }
 Serial.println("TIEMPO 4");
 break;
   
 case 5:   //Potentiometer turned upto 76-100%
 if((ledState == HIGH) && (currentMillis - previousMillis >= (OnTime + 6000)))
 {
 ledState = LOW;  
 previousMillis = currentMillis;  
 digitalWrite(led, ledState);  
 }
 else if ((ledState == LOW) && digitalRead(start)== HIGH)
 {
 ledState = HIGH;  
 previousMillis = currentMillis;  
 digitalWrite(led, ledState);  
 }
 Serial.println("TIEMPO 4");
 break;
   
 case 6:   //Potentiometer turned upto 76-100%
 if((ledState == HIGH) && (currentMillis - previousMillis >= (OnTime + 6000)))
 {
 ledState = LOW;  
 previousMillis = currentMillis;  
 digitalWrite(led, ledState);  
 }
 else if ((ledState == LOW) && digitalRead(start)== HIGH)
 {
 ledState = HIGH;  
 previousMillis = currentMillis;  
 digitalWrite(led, ledState);  
 }
 Serial.println("TIEMPO 4");
 break;
   
 case 7:   //Potentiometer turned upto 76-100%
 if((ledState == HIGH) && (currentMillis - previousMillis >= (OnTime + 6000)))
 {
 ledState = LOW;  
 previousMillis = currentMillis;  
 digitalWrite(led, ledState);  
 }
 else if ((ledState == LOW) && digitalRead(start)== HIGH)
 {
 ledState = HIGH;  
 previousMillis = currentMillis;  
 digitalWrite(led, ledState);  
 }
 Serial.println("TIEMPO 4");
 break;
 }

 last_range = range;

 digitalWrite(led, ledState); 
 delay(100);        
}
6

Thank's Tammytam i see it good! I'll try the code at a time. I notice you the results.

Robin2, Its ok Robin i want two conditions:

Condition 1: I have diferents time on for a led in each case. I turn on led with a start boton and time on starts, when time is over the led is turned down and here should sound my buzzer for 1 minute and then it turn down just once. But obviously it needs be repeated every my led output is turned on.

Condition 2: I have the case 0, where the led time on can be interrupted and the led output is turned down when this case is true. Also i need my buzzer turn on for a second and then it should down (it to notice that led was turned down). It needs repeat each i starts the led on.

Do you have any option? Thanks!

7

ArmandoAmaros:
Robin2, Its ok Robin i want two conditions:

Perhaps I am misunderstanding things - what is not clear to me is what triggers the conditions.

I was guessing from your code that when the potentiometer is at Zero everything is off and case 0 is triggered. Then you turn it and case 1 is triggered (or case 2 etc). And when it goes back to Zero (case 0) it should make some noises and switch off.

From your Original Post

case 0:   //Potentiometer turned between 0-25%
   ledState=LOW;
//Here the led should turns on just once and only for a second

When I wrote my previous paragraph it occurred to me that you are using case0 to start things and there needs to be a case before that to represent the Zero position when things should be switched off.

I hope that makes sense...

Let me set out the way I would do the steps

Step0 - pot at Zero position - all off.
if Step0 is reached while the system is working make a noise and switch off / reset counter / whatever
Step1 - pot at first position
start things happening
Step3 - pot at second position
do more things

...R

8

Excuse me Robin2 and Tammytan, i´ve been working in my project and i found a way to make my objetive. This code is probably very extensive but it´s working good, only not sound my buzzer when i move the selector to my off position. I´m working in this and i have the idea, as you tell me with a previous state comparision, i´m going to try it and if you have an idea to optimize my code is wellcome.
Thank´s!!

const int min = 0;     
const int max = 1023; 
const int reac=7;
const int start=4;
int reacState = LOW;                  
long OnTime = 120000;                     
unsigned long previousMillis = 0; 
int buzzer=9;
int lamp=12;
int vent=3;

void setup()  {
 pinMode (buzzer, OUTPUT);
 pinMode (reac, OUTPUT);
 pinMode (lamp, OUTPUT);
 pinMode (vent, OUTPUT);
 Serial.begin(9600); 
}
void loop() 
{  
 if(reacState== HIGH)  {
 digitalWrite(vent, HIGH); }
 else {
 digitalWrite(vent, LOW); }
 digitalWrite(lamp, HIGH); 
 int sensorReading = analogRead(A0);
 int range = map(sensorReading, min, max, 0, 7);
 unsigned long currentMillis = millis();
 
switch (range) {
case 0:
 reacState=LOW;
 Serial.println("OFF");
 if(digitalRead(start) == HIGH)  
 {    for (int x = 0; x < 3; x++) {
      digitalWrite(buzzer, HIGH);
      digitalWrite(vent, HIGH);
      delay(100);
      digitalWrite(buzzer, LOW);
      digitalWrite(vent, LOW);
      delay(100);  }}
 break;

case 1:    
 if((reacState == HIGH) && (currentMillis - previousMillis >= OnTime)) {
   for (int x = 0; x < 1; x++) {
      digitalWrite(buzzer, HIGH);
      delay(2000);
      digitalWrite(buzzer, LOW);
  }
 reacState = LOW;  
 previousMillis = currentMillis;  
 digitalWrite(reac, reacState); 
 }
 else if ((reacState == LOW) && digitalRead(start)== HIGH)
 {
 reacState = HIGH;  
 previousMillis = currentMillis;   
 digitalWrite(reac, reacState); 
 }
 Serial.println("TIEMPO 1");
 break;

 case 2:     
 if((reacState == HIGH) && (currentMillis - previousMillis >= (OnTime + 180000)))  
 {
   for (int x = 0; x < 1; x++) {
      digitalWrite(buzzer, HIGH);
      delay(2000);
      digitalWrite(buzzer, LOW);
  }
 reacState = LOW; 
 previousMillis = currentMillis;  
 digitalWrite(reac, reacState);  
 }
 else if ((reacState == LOW) && digitalRead(start)== HIGH)
 {
 reacState = HIGH;  
 previousMillis = currentMillis;   
 digitalWrite(reac, reacState); 
 }
 Serial.println("TIEMPO 2");
 break;  
....etc.