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-   -   Unique project - mobile CCTV system (http://www.diychatroom.com/f18/unique-project-mobile-cctv-system-39615/)

mobilecam 03-04-2009 08:35 AM

Unique project - mobile CCTV system
 
I have a strange situation that I am trying to find a solution for. I am looking to make a mobile CCTV system for scientific research. I am looking to have only one camera attached to each mobile unit. Each unit will include a mini DVR player, a small 24 led camera, both of which will be connected to a battery. I just need to know if it is doable, and if not, what can I do to make it possible. My budget is for around $1000 per mobile unit, and I am looking to make 5-6 of them. Here are the supplies that I am going to need to purchase.

First, here is a little background on the project and what the needs are specifically. We are conducting research on a bird that nests on the ground. Therefore, we need a small camera that can be set up within 3 feet of the nest. The camera therefore, is small, with a small number of LEDs because we will be using it up close at night so donít need much illumination. Also, the wavelength of the LEDs is 940nm, so that potential predators cannot see the visible light. The cable to the camera will be at least 50ft so that we can change out the SD card without disturbing the nest. The battery and DVR will be placed inside a pelican case, to protect them from the elements.

To make things easy, all three operate at 12V.

DVR: http://www.supercircuits.com/Recorde...MDVR14-3#specs
-12v, 120mA
-Input voltage 3.7v-14.5v

Camera: http://www.pinhole-security-cameras....sible_LEDs.htm
-12v
-unknown amps

Battery: http://www.batteriesplus.com/pc-32624-73-Werker%2012V%2026AH%20AGM%20Battery%20w-%20Nut%20%20Bolt%20Terminal%20-%20WKA12-26NB.aspx
-12v 26amp

What I want to know is if these three things would be compatible, even with different amps? Someone on another project made something similar but used a 5v DVR. He used a voltage converter from the battery to the DVR but his system would shut down. He claims that it was due to the voltage of the VC being higher (2ah) than the DVR (1ah). Would this be the case with my system?

The connectors we would be using for this system are alligator clips attached to the battery that will be wired to a Y splitter and go to the DVR and camera. Also included is a male power plug and a female power jack.

Is this doable?

InPhase277 03-04-2009 08:56 AM

Obviously, this is doable. The other guy's setup failed because he likely drained his battery. And the bigger the battery, the longer the life. Maybe you could look into a trickle solar charger too.

Also, 940 nm is in the near infrared, and is sorta visible to well dark-adjusted human eyes, so won't potential predators, such as cats, be able to see it pretty good?

mobilecam 03-04-2009 09:49 AM

I am just happy that it sounds doable. I was just worried that since amps are different between them, that there might be some issues. I ask because the other researcher said his problem was due to the amps. Now I wonder if maybe there was some faulty wiring or he wasn't charging the battery often enough.

There will be some visible light from the IR but many predators cannot see red anyway, but we are just trying to be cautious, just in case some can see it. The 850nm obviously will show more red than the 940nm and there have been other research that suggests many predators cannot see the visible light in 940nm cameras.

Thanks for your response!

Billy_Bob 03-04-2009 10:48 AM

Anything can be done, the only question is how much will it cost! :)

What you can do is get a DC amp meter and measure the amperage the devices use and calculate the battery size you will need. Or just hook it up and see how long it works before the battery goes dead. Check into solar chargers too.

As to placing this outside, I've seen similar things. What I saw had lots of silicone sealing on everything to keep the rain out. And bugs can crawl into holes and mess up electronics. So be sure rain can't get in, and if vents are needed due to heat, place screen door screen over the vents so bugs can't crawl in.

mobilecam 03-04-2009 11:22 AM

I really appreciate the suggestions! I guess the only thing I dont know the amps of is the camera, but it probably is pretty low because of the low number of leds.

I will be purchasing one unit and testing it within the next week or so.

We will definitely be sealing up the pelican case, don't need any unwanted critters messing up the system. Nothing we can really do about the cables running from the camera though, I suspect I will be replacing those a couple times this summer :)

My next issue is the weatherproofing of the camera. Due to its low cost, I imagine its quality is also questionable. It is a small camera so I doubt there will be any issues making something that will fit. Gotta love a university budget system! I wish I had more money for better equipment :whistling2:

Billy_Bob 03-04-2009 11:45 AM

As to the cable, rats like to chew on some electrical cables. But they don't like shielded cable! Shielded cable has a metal wire braid around the outside. If you are using coax, then this would have the braid. If a two conductor cable, you can get shielded cable two conductor.

What might be cheaper is to use plastic PVC pipe to protect the cable. Easy to install and cut.

InPhase277 03-04-2009 12:57 PM

Quote:

Originally Posted by mobilecam (Post 240068)

My next issue is the weatherproofing of the camera. Due to its low cost, I imagine its quality is also questionable. It is a small camera so I doubt there will be any issues making something that will fit. Gotta love a university budget system! I wish I had more money for better equipment :whistling2:

No, don't spend money on better equipment. The heart of all good field science is using the cheapest stuff possible and then making it better with off-the-shelf components. You could use a piece of PVC pipe, capped at one end with a removable screw plug, that the camera fits in. Use a piece of plexi-glass glued to the other end for transparency.

You may even be able to get even cheaper indoor cameras and weatherproof them this way. Of course, you need to do a little research to make sure your clear window is also transparent to light at 940 nm. Some plastics are clear to visible light but opaque to infrared.

jogr 03-04-2009 01:49 PM

Have you checked out the sophisticated game cameras that are commercially available? Some do video, have IR lights (which you could probably change to whatever wavelength LEDs you want) and have remote downloading by phone so you don't have to approach the camera. All are already weather resistant and less than $1000.


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