Hello. I am trying to make a UV curing box for my 3d prints. I can display the time for curing on a 16x2. I can start the countdown and display it on the LCD again but countdown stops after 1 second. What am I doing wrong?
#include <TinyWireM.h>
#include <LiquidCrystal_I2C.h>
#define GPIO_ADDR 0x3f
LiquidCrystal_I2C lcd(GPIO_ADDR,16,2);
const int relay = 5;
const int buttonPin = 4; // the number of the pushbutton pin
const int pot = 3;
const int buzz = 2;
const int ledPin = 1; // the number of the LED pin
int buttonState = 0;
int sensorValue = 0;
int timer = 0;
void setup() {
pinMode(ledPin, OUTPUT);
pinMode(relay, OUTPUT);
pinMode(buzz, OUTPUT);
pinMode(buttonPin, INPUT);
pinMode(pot, INPUT);
TinyWireM.begin();
lcd.init();
lcd.backlight();
}
void loop() {
buttonState = digitalRead(buttonPin);
if (buttonState == HIGH) {
buttonPress();
} else {
mainScreen();
}
delay(20);
}
void buttonPress(){
buttonState == LOW;
int sec = 59;
while(timer > -1){
digitalWrite(ledPin, HIGH);
digitalWrite(relay, HIGH);
lcd.clear();
lcd.setCursor (0,0);
lcd.print("Time left:");
lcd.setCursor (0,1);
lcd.print("Press to cancel");
lcd.setCursor (12,0);
lcd.print(timer - 1);
lcd.setCursor (13,0);
lcd.print(":");
lcd.setCursor (14,0);
lcd.print(sec);
sec = sec - 1;
if(sec < 1){
timer = timer - 1;
sec = 59;
}
delay(1000);
if (buttonState == HIGH){
break;
}
}
digitalWrite(ledPin, LOW);
digitalWrite(relay, LOW);
digitalWrite(buzz, HIGH);
delay(300);
digitalWrite(buzz, LOW);
delay(300);
digitalWrite(buzz, HIGH);
delay(300);
digitalWrite(buzz, LOW);
delay(300);
digitalWrite(buzz, HIGH);
delay(1000);
digitalWrite(buzz, LOW);
mainScreen();
}
void mainScreen(){
sensorValue = analogRead(pot)/100;
timer = sensorValue;
lcd.clear();
lcd.setCursor (0,0);
lcd.print("UV Exposure Time:");
lcd.setCursor (0,1);
lcd.print(sensorValue);
lcd.setCursor (3,1);
lcd.print("minute(s)");
}
I cannot say this is perfect approach but what I am trying to do is to create a countdown on the lcd and keep the uv leds on meanwhile. While the countdown continues, user can interrupt the countdown by pressing the same button that starts the countdown.
I checked the blink without delay example and what I understood is keeping an eye on the time constantly and do something on the set interval. I liked it but I am not sure how should I implement this to my example and why it is necessary.
"Break" usage is to kill the countdown while loop. Is this a wrong way to use?
The while loop I created is in the void loop section. My intention was to keep the arduino in the loop I created until the timer is set to zero. But I guess main loop prevents the loop I created to keep the timer on so the loop I created runs only 1 time although it should run as many time as the second version of the potentiometer value.
One possible reason is because your code needs to keep checking the button during the countdown, in case it is pressed again. It can't do that during delay(1000), so any button press could easily be missed, unless you held the button down for at least a second, so that it is held down at the point between delay(1000)s when it gets checked. But you can check the button more frequently, like 10 or 100 times per second, while still using delay(). You could use delay(10) and have a third variable to count the hundredths of seconds, as well as the variables to count seconds and minutes that you have now.
But if you try that, you will immediately get another problem: You won't be able to press the button to start the timer for a short enough time to prevent it stopping again 10ms later. You need to check out the "state change" example sketch to see how that handles detecting button presses.
Wow, that worked perfectly. I tried to comprehend the code completely but I failed:( Feeling so stupid now.
I made this, this complicated because I wanted to use 1 button I think. I am writing down all the process and trying to understand the logic.
Btw, the seconds part does not fit the screen so I changed it to lcd.setCursor (11, 0); instead of lcd.setCursor (12, 0);. And lcd.print("minute(s)"); part refreshes itself so fast that it is hard to read it but it is alright. I have bigger problems now:)
Change your exposure time to be more like the countdown. Do not clear the display and constantly redraw it. rather, just update the value and maybe use MM:SS.
