Sleep mode on the arduino for how long?

Projects Programming
1

Hello i was looking to build my own remote for my lighting and i found a transmitter and receiver sketch so it can run on a coin cell battery. Everything works and sketch is below. But i was wondering one thing. How long does it really take to the arduino to sleep and wake up when a button is pushed?

#include <IRremote.h>
#include "LowPower.h"
IRsend irsend;
const int button1 = 4; //Turn Light On
const int button2 = 5; //Mode
const int button3 = 6; //Turn Light Off
int timer;

void wakeUp(){
 timer = 0;
}

void setup() {
  pinMode(button1, INPUT);
  pinMode(button2, INPUT);
  pinMode(button3, INPUT);
  timer = 0;
}

void loop() {
  attachInterrupt(0,wakeUp, HIGH);
  while (timer < 3000){
  if (digitalRead(button1) == HIGH){
  timer = 0;  
  delay(50);
  irsend.sendNEC(0x34895725, 32);} //Turn Light On

  if (digitalRead(button2) == HIGH){
  timer = 0;
  delay(50);
  irsend.sendNEC(0x56874159, 32);} // Light pattern Mode

  if (digitalRead(button3) == HIGH){
  timer = 0;
  delay(50);
  irsend.sendNEC(0x15467823, 32);} //Turn light Off
  
   delay(1);
   timer = timer + 1;
}
  LowPower.powerDown(SLEEP_FOREVER, ADC_OFF, BOD_OFF);}

What i mean sense the wake up is 0ms how long does it really take to wake up then go back to sleep.

2

Wakeup from the deepest sleep modes requires that the crystal oscillator restart, which takes about 65ms.

3

Hello Westfw thank you. So waking up the arduino board is pretty quick then. I'm using a pro mini board for this project.

4

Yep. If you consider 65ms "quick." And that's the "deep sleep" mode; the modes that leave the clock running wake up within a relatively small number of clock cycles (well under 1ms.)

5

westfw:
Yep. If you consider 65ms "quick." And that's the "deep sleep" mode; the modes that leave the clock running wake up within a relatively small number of clock cycles (well under 1ms.)

I believe that this is wrong. The 16 MHz Arduinos have their clock source fuse bits set to "Crystal Oscillator, slowly rising power". The datasheet has a table that says "Start-up Time from Power-down and Power-save", and the value given is 16K CK. 16,000 clock cycles is 1 ms. The 65 ms figure you are getting is part of the "Additional Delay from Reset" figure. Waking up from sleep is not a reset, so that time is irrelevant.

There is no sleep mode called "deep sleep", you probably mean Power-down.

josephchrzempiec:
Hello Westfw thank you. So waking up the arduino board is pretty quick then. I'm using a pro mini board for this project.

Which one? There's 4 variants:

Arduino Pro or Pro Mini (5V, 16 MHz) w/ ATmega328
Arduino Pro or Pro Mini (3.3V, 8 MHz) w/ ATmega328
Arduino Pro or Pro Mini (5V, 16 MHz) w/ ATmega168
Arduino Pro or Pro Mini (3.3V, 8 MHz) w/ ATmega168

3 of the 4 have the same clock source fuse settings, only the 8MHz ATmega168 is different. It'll actually have a quicker wakeup time.

The 8MHz ATmega328 variant will take double the amount of time I quoted above, 2 ms.