Timer, Sleep mode and low consumption

Hello guys, I'm from Uruguay and I'm developing a project with Arduino. It's my first time with it, so I've some questions to post here. :)

  1. I need to do an action every 60 min with Arduino. The problem here is that I need to be care of the low consumption. I've been looking for timers, sleep modes, also the watch dog mode, but I don't know if it is possible to combine low consumption with an action every 60 min.

  2. In some forums I read that Arduino can crash sometimes, is this possible?

Can you help me with this questions? Thanks!

  1. Yes, read here. http://www.gammon.com.au/forum/?id=11497

  2. Will only crash if your sketch does not hande unexpected inputs.

Thanks for the answer! So, If I use sleep mode, I'll couldn't use a timer?

Depends on which sleep mode - some leave timers on, others don't. Many use the watchdog timer to create an interrupt (every 8 seconds?) and then go from there.

ecastellano: Thanks for the answer! So, If I use sleep mode, I'll couldn't use a timer?

You don't say which Arduino you have. On an Uno or something similar with an ATmega328P, Timer2 can wake the MCU from certain, but not all, sleep modes. The Watchdog Timer can wake the MCU from any sleep mode. A third option is an external wake-up source like a real-time clock. Timer2 will only be as accurate as the Arduino's system clock, the Watchdog will be worse, and will tend to run slow. If the 60 minutes needs to be fairly accurate, I'd use an RTC.

Be careful which board you choose. Arduino boards have other circuitry that continues to draw power even when the MCU sleeps, so are not good choices for low-power projects.

i found this useful link too http://donalmorrissey.blogspot.com.au/2010/04/putting-arduino-diecimila-to-sleep-part.html its a 5 part blog about sleep timers. it explains everything.