I am trying to set up the low power module for an instance case, I have installed the low power library but when I am using the line

LowPower.powerDown (SlEEP_5S, ADC_OFF, BOD_OFF) ; 

It is throwing an error stating that the 'SLEEP' was not declared in the scope. Any suggestion for that ? Do I have to include a library for sleep too ?

#include "LowPower.h"
  /// DON' t worry about the setup and loop, i have defined all those.

This set of code is in

  void Loop()  
       LowPower.powerDown (SLEEP_10S, ADC_OFF, BOD_OFF) ; 
  • 1
    SlEEP_5S ... should that be SLEEP_5S ? Commented Feb 15, 2019 at 8:20
  • Sorry ! I didnt get you
    – kaushik
    Commented Feb 15, 2019 at 8:42
  • you can't see the difference between SlEEP and SLEEP? Commented Feb 15, 2019 at 8:47
  • nope i tried that, doesn't work.
    – kaushik
    Commented Feb 15, 2019 at 9:05
  • 1
    Void instead of void? An else without an if? Your program will have many more problems right now. Note that the language is case sensitive. Commented Feb 15, 2019 at 9:49

1 Answer 1


There is no 5 or 10 second sleep. You can't just arbitrarily choose how long to sleep for. The watchdog timer only has specific periods (defined by dividing the clock by a set amount) that it can sleep for:

enum period_t

To sleep for 5 seconds you would need to sleep first for 4 seconds, then wake up, and then sleep for a further 1 second after that. For 10 seconds sleep for 8 seconds followed by 2 seconds.

Note that they aren't exact values, however, since the watchdog oscillator is very crude and varies wildly in frequency with both temperature and power supply voltage.

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