Solar long term project

[keesvanbemmel]

Hi there,

I'm planning a long term timelapse project with my pi which is solar powered. I've ordered a Witty Pi http://www.uugear.com/witty-pi-realtime ... pberry-pi/ to be able to gracefully shutdown/startup the pi on a schedule. I want to take a picture every 15 minutes between 5am and 10pm for more than a year and a half.

In my mind I have two options:
1. Let the pi startup at 5am and shut it down at 10pm and take a picture every 15 minutes, this consumes more power
2. Let the pi startup every 15 minutes, take a picture and gracefully shut it down. This will consume far less power but in my opinion will be more error prone due to a lot (50+) reboots/startups/shutdowns a day.

Any thoughts on which option is best? Will an SD and pi be able, if shutdown neatly, to handle that many cycles (around 30k in total) And are there any other options I'm missing?

Thanks for any help!

Regards,

Kees.

[sprinkmeier]

I'd be tempted to run 2 for redundancy, one in each mode, and keep an eye on them to see which one performs better.

How are you going to deal with clock-drift?

[keesvanbemmel]

2 will be tricky, as I have little room AND it is a remote location, monitoring them will be very difficult as well.

I was aware of the clock drift on the pi. The Witty pi of UUGear should resolve this as I don't think that one has too much clock drift. Would you happen to have any experience with clock drift on the witty pi?

[sprinkmeier]

(internet oopses have now eaten 2 of my posts.... )
rig up a test system, test the 2 options
network time servers should take care of drift, assuming you occasionally connect to harvest pics
GPS is the obvious non-networked solution.
The cool solution to drift would be an image analysis of the pics taken (dusk/dawn detection, digital sundial based on shadows, position of the sun/moon)

Hoping for third time lucky...

[Robin B]

I'm planning a similar project, albeit with a permanent power supply, but given I want each shot to be accurately time stamped I'm using the PiFace Real Time Clock "shim" which is powered by a 3v CR1220 button battery with a claimed 2-year life. Here's the user manual:- http://www.piface.org.uk/assets/piface_ ... kguide.pdf

[sprinkmeier]

... I want each shot to be accurately time stamped ... claimed 2-year life.

I would assume that "2 year life" means "2 years of life on a single battery", not "2 years of drift-free operation".
The manual doesn't mention drift, so go by the rule "if they're not bragging about it then they're not proud of it".

My PC clock drifts, only a few seconds a day last time I checked, but enough to become annoying in the long run, so I run ntp or chrony on all my PCs.

[CarnageTR]

If you take pics in automode you can use arduino attached to pi. Pi gives arduino rtc info each day. Arduino takes care of shooting process at night pi opens and takes all pics from camera and upload to remote server via from or rsync. Then closes itself.

Dslr cameras has remote control interface that works with simple shortcut. Arduino can easily handle with it independently from shutting speed and you can get exact timing.

[Mortimer]

That would be assuming he isn't intending to use a PiCam.

[keesvanbemmel]

That would be assuming he isn't intending to use a PiCam.

An I am intending to use the picam! still all input is welcome!

[RaTTuS]

use sunwait to find dawn at the location
startups and shutdowns should be fine as long as your not writing to the SDcard [apart from the images]
log to ramdisk
rsync to remote server

[tater1337]

If you take pics in automode you can use arduino attached to pi. Pi gives arduino rtc info each day. Arduino takes care of shooting process at night pi opens and takes all pics from camera and upload to remote server via from or rsync. Then closes itself.

Dslr cameras has remote control interface that works with simple shortcut. Arduino can easily handle with it independently from shutting speed and you can get exact timing.

I thoguth he was doing this somewhere remote, hence no internet or other network