OK. I read through the links you sent on millis. The reference link is for using millis as a "how long has something been running" way, no?
The tutorial seems more comprehensive and it says it makes for more flexible code. Please forgive my ignorance, but, I am trying to understand how to apply it in my instance. I have found out how to post my sketch and hope it helps.
/*
* Turn 4 LEDs split into 2 sets on and off with special characters
* sent over the serial connection with only 1 LED of each set
* allowed on at a time.
* If the 2nd LED is commanded on, the first will be turned off
* prior.
*/
int led1 = 13; // led is hooked up to this pin
int led2 = 12; // led is hooked up to this pin
int led3 = 11; // led is hooked up to this pin
int led4 = 10; // led is hooked up to this pin
char LED1 = '1'; // ascii LED 1 on
char OFF12 = 'o'; // ascii leds 1&2 off
char LED2 = '2'; // ascii LED 2 on
char LED3 = '3'; // ascii LED 3 on
char OFF34 = 'f'; // ascii leds 3&4 off
char LED4 = '4'; // ascii LED 4 on
char ON13 = '5'; // ascii LED 1&3 on
char AllOFF = 'a'; // ascii ledsAll off
char ON24 = '6'; // ascii LED 2&4 on
int ledState1;
int ledState2;
int ledState3;
int ledState4;
char nextChar;
void setup()
{
Serial.begin(9600);
pinMode(led1, OUTPUT);
digitalWrite(led1, LOW);
ledState1 = LOW;
pinMode(led2, OUTPUT);
digitalWrite(led2, LOW);
ledState2 = LOW;
pinMode(led3, OUTPUT);
digitalWrite(led3, LOW);
ledState3 = LOW;
pinMode(led4, OUTPUT);
digitalWrite(led4, LOW);
ledState4 = LOW;
}
void loop()
{
if (Serial.available())
{
nextChar = Serial.read(); // read just one character
if (nextChar == LED1) // check for '1'
{
ledState1 = HIGH;
ledState2 = LOW;
Serial.println("LED 1 On");
}
else if (nextChar == LED2) // check for '2'
{
ledState1 = LOW;
ledState2 = HIGH;
Serial.println("LED 2 On");
}
else if (nextChar == OFF12) // check for 'o'
{
ledState1 = LOW;
ledState2 = LOW;
Serial.println("1/2 Off");
}
else if (nextChar == LED3) // check for '3'
{
ledState3 = HIGH;
ledState4 = LOW;
Serial.println("LED 3 On");
}
else if (nextChar ==LED4) // check for '4'
{
ledState3 = LOW;
ledState4 = HIGH;
Serial.println("LED 4 On");
}
else if (nextChar == OFF34) // check for 'f'
{
ledState3 = LOW;
ledState4 = LOW;
Serial.println("3/4 Off");
}
else if (nextChar == ON13) // check for '5'
{
ledState1 = HIGH;
ledState2 = LOW;
ledState3 = HIGH;
ledState4 = LOW;
Serial.println("LED 1/3 On");
}
else if (nextChar == ON24) // check for '6'
{
ledState1 = LOW;
ledState2 = HIGH;
ledState3 = LOW;
ledState4 = HIGH;
Serial.println("LED 2/4 On");
}
else if (nextChar == AllOFF) // check for 'a'
{
ledState1 = LOW;
ledState2 = LOW;
ledState3 = LOW;
ledState4 = LOW;
Serial.println("All LED Off");
}
digitalWrite(led1, ledState1);
digitalWrite(led2, ledState2);
digitalWrite(led3, ledState3);
digitalWrite(led4, ledState4);
}
}