I have been experimenting with cheap, small cameras that could be used to capture lots of footage over a long period of time.
Results from the 30 second timelapse setting: 2.05gb and 6734 files – 2 days 8 hours or 3377 minutes. I also did it on a 5 second timelapse: 12.0gb and 39,621 files – 2 days 1 hour or 2972 minutes (I’ve not turned this one into a video)
The difference in battery life (or lack thereof) between the two tests is quite interesting. If I understand correctly, the camera will effectively draw from the external battery (10,000mah) before using the internal which I believe is only 250mah. Despite the one test writing 6x more data than the other, this has only reduced the total life by 7 hours, roughly a third. Therefore I think the external battery is constantly outputting, even at a low level while it is plugged in. Either that or it is the camera standby mode.
All in all the equipment used cost about £50 and could be reused in various other ways. The weather was okay here, I have tried out a few quick boxes and weatherproof enclosures that would do the job. I would love to add a solar panel to it, this would probably require building things from scratch, although there are off-the shelf external batteries that come with panels. It still doesn’t solve the charge controlling issue but it would definitely extend the lifespan. I think for most purposes, say at a one or two day event, something like this could be quite easily set up and ‘forgotten about’. This video was put together at Latitude festival over the course of several days, has been useful for monitoring how many visitors came through, which exhibits they spent time at, whether we had a busy pitch or not and so on.
As the internal battery is “saved” for last, it is quite easy to swap out batteries without interfering too much with the process. I would estimate you would get at least an hour of time in between the external battery running out and the internal running out too. Even if the camera was in a remote spot, you might be able to get away with swapping the external battery out every 48 hours.
There are some extremely clever algorithms for automatically crowd counting from stills/video out there, but at a basic level you could just take a small sample of frames combined with a measurement of the area covered and figure out some basic crowd density figures by hand.
This could be really useful for free events, parades and processions where there is no central box office and no single entry point to the site or venue. Even then, trying to count crowds with clickers could be open to error.
For more check out the following: Chuck Lohr’s 808 pages : http://www.chucklohr.com/808/index.shtml Brinno timelapse cameras : http://www.brinno.com/ Cam-do equipment for GoPros : http://cam-do.com/GoProTimeController.html