How to delay code execution after boot sequence?

Projects Programming
1

I want my Uno R3 to wait 2 seconds between booting up and executing the following code, but I can't find a coding example for a delay placed outside a loop.

int controlPin = 3;
void setup()
{
  Serial.begin(9600);
  TCCR2A = 0x23;
  TCCR2B = 0x09;  // select clock
  OCR2A = 79;  // aiming for 25kHz
  pinMode(controlPin, OUTPUT);  // enable the PWM output (you now have a PWM signal on digital pin 3)
  OCR2B = 15;  // set the PWM duty cycle to 19%
}

void loop()
{
  OCR2B = 62;
  delay(5000);
  OCR2B = 120;
  delay(5000);
}

I'm a total newbie so I probably missed something simple, but any help will be appreciated.

2

Will delaying at the start of the setup function not do?
Do you want to delay even before main() is called? If so, why?

3

fire-flare:
I want my Uno R3 to wait 2 seconds between booting up and executing the following code, but I can't find a coding example for a delay placed outside a loop.

Why? You want it to wait before it boots?

4

How about:

void setup()
{
  delay (2000);
...
5

pYro_65:
Will delaying at the start of the setup function not do?
Do you want to delay even before main() is called? If so, why?

The code creates a 19% control signal for PWM computer fans, without the signal the fans spin at 100%
Large fans, like the ones I intend to use, need a 1-2 second period of full power to build the inertia needed for continuous rotation; Otherwise it's like starting a car with a low battery and the engine never fully turns over.

I'm using a small fan to test the code which can turn over at a 1% duty cycle, and it shows that my arduino is sending the 19% signal the instant power is applied.

6

Sorry, I'm not seeing any change with that added.

7

I'm seeing an over 3 second delay from when reset is released:

934×247 25 KB

However then it immediately goes to 80% duty cycle so you better look at your timer parameters:

929×220 27.2 KB

8

Wow, I was way off.

I found that the arduino wasn't receiving power at all due to a bad connection on my shield. The fan slowed down when the ground lines made contact.

Now the board's LED lights up and I was able to tweak the code to get the effect I need. (Last time I blindly copy/paste code without looking it over)

I also brainstormed a way to to keep the signal going: Make the loop last longer than my computer's average uptime. :smiley:

int controlPin = 3;
void setup()
{
  Serial.begin(9600);
  TCCR2A = 0x23;
  TCCR2B = 0x09;  // select clock
  OCR2A = 79;  // aiming for 25kHz
  pinMode(controlPin, OUTPUT);  // enable the PWM output (you now have a PWM signal on digital pin 3)
}

void loop()
{
  OCR2B = 79; // set duty cycle for 100%
  delay(1300); // wait 1.3 seconds
  OCR2B = 14; // set duty cycle for 17.5%
  delay(604800000); // wait a week
}