I'd like to make an Arduino play a (2sec).wav file once when it is powered on (via push button) and another when it is switched off i.e. when the push button is pushed there is a 2sec delay and the .wav file plays, then the arduino turns off. What would the best way be to implement this? So far I've come up with:
void loop()
{
//play .wav file
while(1){}
}
or:
void setup(){
//play .wav file
}
void loop(){
//empty
}
An Arduino doesn't understand the concept of "powering off". It is either on (running) or off (not able to do anything).
Your first task must be to design a system whereby the Arduino can control its own power so the Arduino can then go "I have been asked by this external stimulus to switch off. Therefore I will play this sound and then perform whatever actions are required to remove power from myself."
Only when you have worked out how you can get the Arduino to control its own power and still have the ability to manually turn the power on can you begin to think about adding things that happen "when it powers off".
Neither way addresses your second requirement. I would do something like:
void setup()
{
pinMode (OFF_BUTTON, INPUT_PULLUP);
//play .wav file
}
void loop()
{
if (digitalRead (OFF_BUTTON) == LOW) // depending on how it is wired
{
delay (2000); // 2 second delay
// play .wav file
// power self off somehow
}
}
