Hello, I am quite a beginner in electronics now, I used to do some projects about 10 years ago, but I am very rusty now. I am in need for help to design a device for a research project.

I am monitoring the activity of certain insects during morning hours and wanted to use video recording in the field so that I can sample from different places in a single morning and later spend hours watching the videos and recording the activity of these insects in the "comfort" of the lab.

I was thinking on getting a usb mini dvr pinhole cameras, and connect it to a "easy" light-activated relay (like the one on this page: http://www.sentex.ca/~mec1995/circ/actrelay.htm) so that when the sunrises, the relay turns on the camera. I got this idea from a kipkay video on youtube (http://www.youtube.com/watch?v=YWjer8Fhzh0). Now, I would also like to know how easy you think it is to add a timer circuit to the relay so that after 30min-1hr recording the relay shuts off the camera and stays off for the rest of the day (not responding to light), but then everything is reset during the night so that another hour can be recorded on the next day.

The reason for the reset function is to avoid to go to the field everyday to download the videos. I have seen mini dvrs with 8GB memory, as long as the battery does not run out and assuming 30 min - 1h videos, that would be enough for checking the cameras only once every three days. Also I would like to keep everything at low voltages so that the device can work only with batteries.

Please do not spend too much time thinking about this, I just wanted to know an expert opinion on whether this kind of device is feasible and relatively "easy" to build. This is an ongoing experiment and may not have time to build complicate designs, but if you know a relatively easy way to design a circuit with this functions that would be a great help.

Thank you very much in advance.

 

Yes, it is more than feasible, and something I think you personally could achieve yourself with motivation and a bit of research. It should not be a massively difficult circuit and I think you have a good enough foundation on which to build it upon!

What if for instance, one morning at 6 o'clock, it was fairly bright? And the light level was x; and the next morning it didn't reach x light level until 7 o'clock? Just a consideration.

To simplify it and overcome that very problem, you might consider focussing on controlling the on/off with timers, rather than light; equally as achieveable.

 

Thanks eng1ne for the quick reply. The light problem you bring up is very legitimate, thanks for the observation. However, a potential problem with using the clock alone is that the insects' behaviour might be light dependent and not regulated by the insect biological clock (internal self-entraining cycle). This is actually an interesting point for my research that I did not look at deeply enough before. Thanks!

Any suggestion about literature/design that could be on target for my problem? As I said I used to do some projects years ago in high school but after that (already 10 years) I shifted to Biology and I have lost much of my basic designing abilities.

Thanks again

 

I have built a system based around an Atmel 895131 micro, that controls cameras via the USB port. This device has a convienent 8 bit port that provides wake up interrupts, of which I use for various trigger inputs. Several triggers that I've found useful are infrared, trip beam, and RTC alarms.

It may sound complicated, but is truly simple, and the best part is it's flexibility.