A LED blink program by David Mellis ( https://www.arduino.cc/en/Tutorial/BlinkWithoutDelay shows the LED's blinking ON and OFF in equal time spacings (duty cycle).
However I need to use this idea in a situation where the ON/OFF cycles are not equal.
More exactly: I have a program where a message 1 has to be displayed during interval1, then message 2 has to be displayed during interval2.
Moreover, the usage of this display cycle is dependent of a number of conditions being met.
If the conditions are no longer met, the display of message1 and message2 has to stop and the program has to carry on.
However, as soon as the conditions are valid again, then the display cycle of message1 and message2 has to resume flawlessly.
My idea was to use the fact that the millis() setup by David Mellis goes through the statements in the loop twice: once at the start and once at the end of the timing. So I had to figure a way to get these statements ran through twice, and only then go to the statements relevant for timing interval2.
For that I use an intermediate variable: flag1 for interval1 and flag2 for interval2. Something like a bistable multivibrator for those knowledgeable in electronics, with the exception that it takes two triggers instead of one to change state.
Please have a critical look at my code; any comments will be greatly appreciated:
// Draft program to run millis()( instead of delay()
// Purpose is to alternate two texts on a LCD line but with different cycles: message1 display a time interval1,
// messag2 displays a time interval2
// The execution of this program is dependent on a set of conditions: temp1Value>T1 && temp2Value <= T2 || temp2Value>T1 && temp2Value<=T2 && OC=false
//
// The idea is that the execution of the millis()-delayfunction happens the first time the function is called and only when the time-interval has lapsed
// will the millis()-delayfunction be run again.
// Therefor variables must be set to allow interval1 section to be ran a first time and then a second time and only then it is allowed to go to the
// interval2 section. Both interval sections may only run exclusively.
// The purpose must also be that whenever the inital condition is not valid anymore and so the statements are not run anymore,
// that whenever the condition is met again at a later time, the millis()(-dealyfunction can be ran again without error.
const long interval1 = 250; // display time 1 in milliseconds
const long interval2 = 350; // display time 2 in milliseconds
unsigned long previousMillis1 = 0; // display timer 1
unsigned long previousMillis2 = 0; // display timer 2
boolean message1 = true;
boolean message2 = false;
boolean flag1 = false;
boolean flag2 = false;
void setup() {
// put your setup code here, to run once:
}
void loop() {
// put your main code here, to run repeatedly:
unsigned long currentMillis1 = millis();
unsigned long currentMillis2 = millis();
//..lots of previous programming lines not relevant to this post..
if (temp1Value > T1 && temp1Value <= T2 || temp2Value > T1 && temp2Value <= T2 && OC == false) // warning high temp darlington or heatsink
{
warning = true;
digitalWrite(LED_BUILTIN, HIGH);
if ((currentMillis1 - previousMillis1 >= interval1) && (message1 = true) || (flag1 = true))
{
previousMillis1 = currentMillis1;
lcd.setCursor (0, 1);
lcd.print("HIGH TEMP WARN!!");
// do whatever else needs to be done during interval1
if (message1 = true) {message1 = false;}
else {message2 = true;
flag1 = false; flag2 = true;}
}
if ((currentMillis2 - previousMillis2 >= interval2) && (message2 = true) || (flag2 = true))
{
previousMillis2 = currentMillis2;
lcd.setCursor (0, 1); // go to start of 2nd line
lcd.print("I=");
lcd.print(outcurr);
lcd.print("A");
lcd.print(" T2=");
lcd.print(outtemp1);
lcd.print("C");
// do whatever else needs to be done during interval2
if (message2 = true) {message2 = false;}
else {message1 = true;
flag2 = false; flag1 = true;}
}
}
// ...lots of subsequent programming lines not relevant to this post..
}
