Go Down

Topic: SD Logger fast dormancy (Read 514 times) previous topic - next topic

AndrewJM

Very very new to Arduino, so any help is appreciated. In essence what I'm trying to do is use a SDLogger (this one: http://www.seeedstudio.com/depot/sdlogger-open-hardware-data-logger-p-723.html) to log readings from an accelerometer. For power saving reasons I'm using set_sleep_mode(SLEEP_MODE_PWR_DOWN) to put the arduino to sleep for 4 seconds between readings. The problem is that these seconds are effectively lost when it comes to logging (the time stamps show the readings happening every second instead of every 4 seconds). Using the time library I'm using the adjustTime function to fix the internal clock but the watchdog timer which wakes the system up isn't sleeping for exactly 4 seconds (it's about 3.5) so what I need is a way to adjust the time in milliseconds or decimals of a second. Alternatively are there any 3V external clocks I could use that wouldn't draw too much power?
Thanks. 

pylon

The watchdog timer waits 4 second from the last wakeup (this can be different, but I haven't seen your code yet).

As for the external RTC: a DS1307 is quite cheap and doesn't use much power. A DS3231 is more accurate and additionally has a programmable alarm to wake the Arduino at specific times.

Go Up
 


Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

Arduino
via Egeo 16
Torino, 10131
Italy