2 timers arduino [ 2x millis() ] - c

Question

I'm having a problem with this code. I know what the problem is, but I can't find a good solution.
I have two functions using millis() - clock() and time().
The function clock() returns date and time and the function time() returns the time that another action is ON.
The problem is that I'm not able to store the time that the time() function is counting. When I call the function 2 times the time starts on 0:00.
I know it's because I'm overwriting the variable every time I call the loop, but I can't find a good solution for it. It seems stupid, but I have this problem for a while.
PS: I would like to have the time information every loop.
Expected results:
Start
2s: press 1 - clock = 2s, time = 0s.
5s: press 2 - clock = 5s, time = 3s.
15s: press 1 - clock = 15s, time = 3s.
20s: press 2 - clock = 20s, time = 8s.
My code:
void clock() {
// ... function that returns date and time;
// ... using millis();
}
void time(){
if (first == 0){
sec_aux = 0;
min_aux = 0;
UtlTime = millis();
first = -1;
}
if(millis() - UtlTime < 0){
UtlTime = millis();
}
else{
sec_aux = int((millis() - UtlTime) / 1000);
}
if(sec_aux > 59){
sec_aux = 0;
min_aux++;
UtlTime = millis();
}
sec = sec_aux;
min = min_aux;
Serial.println("TIME");
Serial.print(min); Serial.print(":"); Serial.println(sec);
}
void loop() {
if (Serial.available()) {
inChar = Serial.read();
}
switch(inChar){
case '1':
time();
clock();
break;
case '2':
clock();
first = 0;
break;
default:
clock();
}
}

Answer 1

Ok, if I understood correctly you want a function that
1) you call once and it resets the counter
2) you call successively and tells you how much time passed
3) you can reset sometimes
If so, you have to ask yourself "how can I reset the timer?". IMHO the best solution is using a flag passed to the function.
And... avoid using the millis function twice ;)
And, BTW, I think you want to perform an action just once when you receive the serial data, so move the switch inside the test...
Here is a sample:
void time(bool reset){
unsigned long currMillis = millis();
if (reset){
sec_aux = 0;
min_aux = 0;
UtlTime = currMillis;
}
while ((currMillis - UtlTime) > 1000)
{
UtlTime += 1000;
sec_aux++;
}
while(sec_aux > 59){
sec_aux -= 60;
min_aux++;
}
// Why do you duplicate the data?
sec = sec_aux;
min = min_aux;
Serial.println("TIME");
Serial.print(min); Serial.print(":"); Serial.println(sec);
}
void loop() {
if (Serial.available()) {
inChar = Serial.read();
switch(inChar){
case '1':
// Show time measure
time(false);
clock();
break;
case '2':
clock();
// Start time measure
time(true);
break;
default:
clock();
}
}
}
EDIT:
Ok, then you want a "stoppable" stopwatch. What I suggest you is to detach the update from the serial interface, so you always have updated values. Or at least that's the way my head works :P
I modified some things. You should
init lastMillis to millis() in the setup
init timeIsRunning to the proper value
call resetTime() inside the setup
Here is the code:
void resetTime()
{
msec = 0;
sec = 0;
min = 0;
}
void updateTime()
{
unsigned long currStep = millis() - lastMillis;
lastMillis += currStep;
if (timeIsRunning)
{
msec += currStep;
while (msec > 1000)
{
msec -= 1000;
sec++;
}
while(sec > 59){
sec -= 60;
min++;
}
}
}
void printTime()
{
Serial.println("TIME");
Serial.print(min); Serial.print(":"); Serial.println(sec);
}
void loop()
{
updateTime();
if (Serial.available())
{
inChar = Serial.read();
switch(inChar)
{
case '1':
// Show time measure
timeIsRunning = false;
printTime();
clock();
break;
case '2':
clock();
// Start time measure
timeIsRunning = true;
break;
default:
clock();
}
}
}