C++/C Arduino Stopwatch code check - arduino

Question

I'm making a stopwatch with an arduino with a vibration motor and a simple button as the interface.
I'm coming to a hold with this project as it just won't work, i've been testing it on my uno with no success so far, I was wondering if someone could give me a quick little run-down and see if they can spot any big issues that i've overlooked.
No errors in code, I think it might be a logical error on my behalf or possibly even an error with my board, but I doubt that!
void setup() {
Serial.begin(9600);
}
int lengthOf(int i)
{
if (i < 0){i = -i;}
if (i < 10){ return 1;}
if (i < 100){ return 2;}
if (i < 1000){ return 3;}
if (i < 10000){ return 4;}
if (i < 100000){ return 5;}
if (i < 1000000){ return 6;}
if (i < 10000000){ return 7;}
if (i < 100000000){ return 8;}
if (i < 1000000000){ return 9;}
return 10;
}
void loop() {
int ButtonSwitch = 4;
pinMode(4, INPUT);
int motor = 5;
int timerA = 0; int timed;
bool checker = false; //checker acts to see if the current state is timing/counting
bool shown; //Shown acts as a check to show if the time has already been shown
if (analogRead(ButtonSwitch) == HIGH && checker == false)//When the button is pressed and the state is false then
{
checker = true;//sets checker to true, meaning the timing should begin
shown = false;//sets the shown variable to false so as to
timerA = 0;//reset timer to a 0 value
}
while (checker == true)//while the timer is active then do the following
{
timerA++;//Increment the timer
if (digitalRead(ButtonSwitch) == HIGH)
{
checker = false;
break;
}
delay(1000);//No needfor the simpleTimer library as I don't need to run any code inbetween each second
}
//Sets the timed to the real value of
timed = lengthOf(timerA);//Grabs the length of timerA (1223 would be 4)
int recTime[timed - 1]; //creates an array of the same length as the timer
//append int to chars and by extent an array
char str[timed];
sprintf(str, "%d", timerA);
int numbers;
for (int i = 0; i < timed; i++)
{
recTime[i] = str[i] - '0';//This grabs STR which is an empty array of the length of the time then sets recTime to be the same
}
while ((analogRead(ButtonSwitch) == LOW) && (checker == false) && (shown == false))//Loop checks that the button is not pressed, the checker is false, and that the time has not been shown,
{
for (int i = 0; i < timed; i++)//
{
for (int o = 0; o < recTime[i]; o++)
{
digitalWrite(motor, HIGH);//Motor set to vibrate
delay(500);//1/2 second delay
digitalWrite(motor, LOW);//motor off
delay(300);//3/10 second delay
}
delay(3000);//3 second delay
}
shown = true;
}
}
If there's any more info I can provide then let me know,
any help is greatly appreciated!

Answer 1

I've read through your code and have a few suggestions. First, let's be consistent and use a digitalRead instead of the analogRead near the top and bottom of the loop routine. Let's move all of your variable declarations before the setup routine. (you will still need to initialize timerA, checker and shown at the top of loop) Also, you only need to set the pinMode for the button once, so we'll move that line to the setup routine and, while we're at it, let's use the variable ButtonSwitch in the pinMode command. e.g.
int ButtonSwitch = 4;
int motor = 5;
int timerA = 0;
int timed;
bool checker = false;
bool shown;
void setup() {
Serial.begin(9600);
pinMode(ButtonSwitch, INPUT);
}
But I think the real problem could be with the logical flow of the program. Assume the loop starts, checker is false and the button is not pressed. When you press the button, checker gets set to true. Immediately after that, within a few clocks ticks, the next block is entered (because checker is true) and it sets checker to false and exits the block if the button is still being pressed. The chances of you releasing the button between the first block and the second is pretty much zero. So your program just keeps setting timerA to 0, then incrementing it by 1 and moving on. The delay(1000) is never reached and timerA never gets above 1, the recTime array will always be defined as recTime[0] and the str array will always be defined as str[1].
In the second block, the while loop, I think you want to change
if (digitalRead(ButtonSwitch) == HIGH) to if (digitalRead(ButtonSwitch) == LOW).
I think if you rectify these issues, you'll be a long way towards getting git working!

Answer 2

In C, when timed is the number of chars needed to write the decimal digits of a number, then you should allocate one more for the terminating '\0'.
char str[timed+1];
Then, I'm wondering what you're doing with the recTime values. Indeed, whenever for a value of 123, str would contain "123", i.e. ['1','2','3'], then retTime would contain [1,2,3].