#15108 - 05/12/05 10:48 AM
Re: Cottage Security Ideas - no power.
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Chris Anderson
addict
Registered: 01/08/04
Posts: 500
Loc: Michigan
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John,
How about a couple of big dogs? 
Chris
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#15109 - 05/12/05 12:35 PM
Re: Cottage Security Ideas - no power.
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John Warner
old hand
Registered: 01/09/03
Posts: 809
Loc: Port Perry, Ontario, Canada
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And the Ocelot/SECU could drop dog food from the ceiling all winter long ala "Back to the Future"? 
Seriously though folks - has anyone run an Ocelot on battery power for an extended period? What does an Ocelot and SECU actually draw when "idleing"? Any creative ideas on low-power sensing? On powering the Ocelot up and down as required?
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#15110 - 05/12/05 05:22 PM
Re: Cottage Security Ideas - no power.
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Mike McDonald
newbie
Registered: 09/24/04
Posts: 22
Loc: New Orleans, LA
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Based on the conditions you describe, I think a bigger problem than powering up and down will be finding batteries that will work in those conditions. Batteries are notoriously poor performers in cold weather.
Exactly how far are you from cellular access? There are relatively inexpensive cellular repeaters that can be used with an external antenna that might offer a communications link if you can solve the battery problem.
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#15111 - 05/12/05 05:33 PM
Re: Cottage Security Ideas - no power.
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Chris Anderson
addict
Registered: 01/08/04
Posts: 500
Loc: Michigan
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John,
You can obviously measure the current draw using a DVOM. I was wondering if you had a couple of big, deep cycle marine batteries wired together if that would work and last all winter. I can tell you from the auto industry that the stuff we keep "awake" while the vehicle is shut down (radio station memory etc) draws maybe 40 mA. This will kill an automotive battery in a few weeks, especially if it's cold. So even the deep cycle option may not last all winter.
If a magnetic contact activates the system, it could be shut off using a relay, but what would turn it back on? Maybe this is a one event system. Once someone prys the door open and steals your stuff, that's it. I keep thinking there needs to be some way to notify you, but there are no phones. Maybe some booby traps or something, but of course you would get sued! Or perhaps just make it the hardest to break into and the thieves will move on to easier prey. I wonder if there are generators that work on a timer that could keep your batteries charged up?
Anyway, my thoughts for now. It presents an interesting challenge.
Chris
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#15112 - 05/12/05 06:36 PM
Re: Cottage Security Ideas - no power.
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Guy Lavoie
Beyond All Hope
Registered: 12/21/02
Posts: 6002
Loc: Montreal, QC, Canada
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Like the others have already said, your biggest challenge is power. There is just no way that any kind of battery will hold a charge over such a long period in such cold weather. An Ocelot draws about 250 mA at 12 volts and a SECU16 maybe 200 mA. Lets just say about 0.5 amps at 12 volts, or about 6 watts. That's 144 watt hours per day. Say that you wnat it to work standalone from Nov 1st to Feb 28th, that's 4 month, or about 120 days. 144 watts times 120 days = 17280 watt hours! That's a lot of power! Just for comparison: with a regular 7 amp hour 12v alarm system battery, you get 84 watt hours, so you would need the equivalent of over 200 such batteries...assuming they could hold their charge all this time!
Some type of solar charging system would definitely be needed. Suppose that you want to batteries to hold 3 days of charge (432 watt hours) that would need about 36 amp hours of charge, or about 5 of those alarm system batteries. If the shortest winter days only give you about 6 hours of good usable daylight for charging, that means your charging system would need to provide 144 watts of power just to replenish a day's use in the 6 available hours. That's 24 watts per hour, or about 2 amps of current at 12 volts. It would be somewhat expensive to get such a device but they are avaialable. Canadian Tire has a 30 watt solar charger at $400 (!), cat # 11-1585-6. And I'd be afraid that this charger would be the next target of a theft...
I think the best solution is simply to leave nothing valuable at the cottage over the winter.
_________________________
"If you don't know what you're doing, do it neatly..."
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#15113 - 05/12/05 07:19 PM
Re: Cottage Security Ideas - no power.
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John Warner
old hand
Registered: 01/09/03
Posts: 809
Loc: Port Perry, Ontario, Canada
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I came across this is while surfing for solutions. It was designed for Wildlife cameras but the controller/PIR is available seperately.
Their Universal V3 will run on 4 AA batteries for over 2 years. It will power on and operate the shutter of a digital camera. The camera batteries should also last all winter if the camera is only on when the PIR gets a detect, especially if I use lithium batteries.
To be safe, I could also use a 6V lantern battery in place of the 4 AA's that run the board. Lead-acid is prone to freezing so not a good option unless I went for a solar cell.
Camera Controller.
If I went the Ocelot/SECU route, it sounds as if
Chris's conclusion about it being a "one time event" would probably be the case.
I also looked at battery-operated stand alone PIR's that sound a siren when tripped. They are fairly inexpensive and, if the siren could be replaced by a small relay, might be enough to power on the Ocelot/SECU?
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#15115 - 05/12/05 11:06 PM
Re: Cottage Security Ideas - no power.
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Stephen
newbie
Registered: 01/01/05
Posts: 24
Loc: Spain
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If its a one time operation, meaning that a magnetic reed switch or simialr switches the system on. Then how long would it take for the system to boot up and become fully operational, as you could miss the actual incident, that triggered the sytem, if it takes more than a few seconds.
Is it windy where the cottages are. A small wind powered generator, similar to those found on yachts might be a better bet. Though this could still seize up during the really cold periods.
Another idea, get a small 12v diesel or gasoline powered generator, with electric start. Wire this up so the Ocelot can turn it on. And say once a week it charges the batteries. Next problem is the fuel tank. Don't know how long 1 tank of fuel would last. Or maybe a combination of generator and solar panel. So when the Solar panel is covered with snow the generator kicks in. Mind you this is all starting to sound expensive.
Good luck
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