I need help in making a project:
My idea is to use an Arduino Mega with a SD card and a small camera module, like OV7670 (I don't need high resolution) to build a surveillance system. I want to install it in a hut so I only have 3G internet connection. I've seen there are 3G modules but they are quite expensive. So I was wondering if I could use a GPRS shield to send pictures every hour to a Dropbox account. I've seen this is possible if done with a Arduino YUN using "temboo.com", but I need to plug a camera and I think YUN is only for WIFI, which I don't have in the hut.
I think the best way to do it would be to program the camera to take a picture every hour and store it in a SD card (mounted on a SD card module) and then separately make the GSM shield send the image to a Dropbox account. The SD card would be erased every week or so.
Would it be possible? I don't mind if it takes 10 minutes to upload the photo.
It would be good to be able to move the camera with a servo as well, from a cellphone.
IMHO I think you are setting yourself a big challenge trying to use a Arduino Mega
I'm not sure how you upload to DropBox, but I suspect it involves SSL, have you looked into whether this has been done on an Arduino, let alone via GSM.
Adding to that, the Mega doesn't really have enough to store decent quality images from the OV7670, as the camera doesn't have any internal ram (Even the FIFO version isnt true Random Access Memory, its sequential access memory)
Put above into one script command (only 4~5 lines code).
Use crontab to schedule run time.
crontab -e
0 * * * * /path_to_executable command
m h dom mon dow command
Minute Hour Day of Month Month Day of week
And your 0 * * * * then translates to "Execute command on every hour, every day, every month, and every weekday, if the minute is 0"