Solar powered night camera

Discussion in 'The Projects Forum' started by madlan, Nov 30, 2011.

  1. madlan

    Thread Starter New Member

    Nov 30, 2011
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    Hi all,

    I was wondering if you could give me some advice on a simple project I'm starting?
    Basically I've been tasked by the Mrs to setup a web cam with night vision so she can view her chickens in their coop at night.

    Here's the camera: http://www.ebay.co.uk/itm/Wireless-WIFI-IP-Camera-IR-11-LED-Night-Vision-Webcam-/140638723025

    It runs off 5v so should be fairly easy to power.

    I'm guessing I need a solar panel and a 6v battery.
    The battery needs to charge during the day and power the camera during the night. (I guess the cameras power supply will be controlled via an LDR?)


    Any pointers on parts I need would be very helpful!
     
  2. wayneh

    Expert

    Sep 9, 2010
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    I'd be tempted to just use an old automotive battery, one with some life left in it but maybe not suitable as we enter the winter months. Plenty of juice for cheap.

    Anyway, it would be useful to understand how this thing actually works. I mean, turning on the LEDs is what takes a lot of power. I wonder if it sits there dark until you ask it for an image? Or is the idea to leave it on continuously?

    If it's the latter, and it's truly drawing 1-2A, that means it's drawing 5-10 watts. Overnight that could add up to 60-120 watt-hours. That means your solar panel will be large and costly, since it needs to capture maybe twice that much during the 8 or so hours that it sees the sun, which won't be every day. Capturing 240 watt-hours in 8 hours means your panel needs to deliver an honest 30 watts. Again, large and costly.

    If the camera can sit there "idling" except for a few minutes of occasional use during the night, that changes things.
     
  3. madlan

    Thread Starter New Member

    Nov 30, 2011
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    Hi, thanks for the reply.

    The specs state 3w. It doesn't need to be on all night, just a few hours after dusk (maybe best running it on a timer instead?). I'll order the camera so I can check it's functions. It may well have a power saving mode, I'm guessing the IR LED's will be manually activated though the web interface.
     
  4. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    The ad says it has a motion sensor, so the LED's are probably off until motion is detected, and therefore current drain would be low. If that is not the cast, a fairly simple circuit with an IR sensor could be built to power the whole thing down when the girls are still. A timer is possible, but would not allow monitoring in response to movement (an intruder, for example.)
     
  5. wayneh

    Expert

    Sep 9, 2010
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    Motion detectors draw a fair current also. Not nearly as much as the IR LEDs and probably not as much as the wi-fi radio either. Just powering a motion detector all night will require a decent solar panel. But, I just saw solar powered landscape lights somewhere that include a motion detector. That could be a cheap starting point, with some of the design challenges already solved.
     
  6. madlan

    Thread Starter New Member

    Nov 30, 2011
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    If the camera is drawing a fairly low current when the motion sensor mode is enabled do you think a panel and battery would suffice?
    I’m also planning on making an automatic door opener for dusk\dawn – this would be 12V so I’m thinking a large 12V battery with a decent panel could power both?
     
  7. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    You could use a 12V battery as long as you add a 5V regulator to it. Large capacity batteries and chargers are getting cheap if you re-purpose a cordless drill or such.

    They you could task the Mrs to get the battery from the coup in the morn to charge it, and replace it in the afternoon. Or if the charger needs overnight (or she only makes 1 trip a day) just get 2 batteries, charge one while using the other.
     
  8. madlan

    Thread Starter New Member

    Nov 30, 2011
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    Last edited: Dec 1, 2011
  9. wayneh

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    Sep 9, 2010
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    One thing you might want to look for is a panel and battery combination that won't require a charge controller. Basically this means a battery big enough that the panel cannot overcharge it. A lead acid battery (nicads, also) can tolerate a constant reverse (charging) current as long as that current is below some threshold. Somebody here probably knows the details.

    Of course a nice panel may well include a charge controller.
     
  10. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    A 45W solar panel with charge controller & 2 12V CFCs is frequently on sale from Harbor Freight @ US $ 149.99, requires 12 V storage battery.
     
  11. madlan

    Thread Starter New Member

    Nov 30, 2011
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    So you can connect the panel directly to a large enough battery? just a diode to protect the panel? Would the combination above work?

    I just need to build a timer to kill it several hours after dusk :)

    Looks good but I'm in the UK :(
     
  12. wayneh

    Expert

    Sep 9, 2010
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    Yes, that's what I meant. (The blocking diode prevents discharge. I don't think it would hurt the panel to omit it.)

    But after more thinking, I'm not so sure it will work for you to omit a charge controller. A lead acid battery can tolerate continuous charging at ~0.001C, or about 100mA for a 100AH battery. I can't find any reference saying you can get by with more than that. But you'll need a panel with quite a bit of current, maybe 500mA, to collect enough power for a few hours operation of your camera. For the battery to absorb that much current safely (when already fully charged), it would have to be ~500AH, and this might be larger than practical.
     
  13. madlan

    Thread Starter New Member

    Nov 30, 2011
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    I guess a 12v to 5v voltage regulator is going to give off quite a bit of heat, wasting energy?
    I could use a 6V motor for the door opener so that no step down is required but all decent solar panels are 12V :confused:
     
  14. madlan

    Thread Starter New Member

    Nov 30, 2011
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    I found out the actual power usage when the LED's are on\off:

    Power Consumption: 4W/6W (Infrared Off/On)
    Power Supply: DC 5V/1.5A

    I have an old car cigarette adaptor that converts 12V to 5V/1.5A - I could take this apart and use the innards.
    So the camera will be drawing about 4W on average, what size battery and panel would I need to power them all night?
    I'm guessing that's rougly 30-40 watt-hours? A 30W panel is quite cheap from eBay and a decent battery from Maplins might do the trick?

    Moving on, I think this module would fit the bill regarding controlling the time the camera is powered. It's designed for lighting but I could probably adapt it to only come on in the evening at dusk for 4 - 5 hours:

    "Assuming the user programmes in 5 hours (of artificial light after dusk) - this means that in the depths of winter the artificial lights will turn on at around 4:00pm (dusk) and stay on until around 9:00pm. The artificial lights will then turn off and stay off for 9 hours - until in this example 6:00am. The artificial lights will then turn on again, and stay on until dawn - in this example until around 7:30-8:00am. After dawn, the controller will go to sleep for four hours so that if after dawn a very large dark cloud covered the sun for a long time the controller will not think that dusk has arrived again."

    http://www.reuk.co.uk/buy-REUK-SUPER-POULTRY-LIGHTING-CONTROLLER.htm
     
    Last edited: Dec 1, 2011
  15. wayneh

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    Sep 9, 2010
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    Looks like you're on your way, but I just wanted to express concern about using an adaptor at 100% of its rating. It may well be OK and work forever, but I'd sure feel better if it was rated at least 20% higher or so, above and beyond the expected draw. Check it when the IR LEDs are on, and make sure it's not overheating. If you're mucking about in its innards, you might be able to add some heat dissipation, even just air flow. A fuse on the low side wouldn't be a bad idea either.
     
    Last edited: Dec 2, 2011
  16. madlan

    Thread Starter New Member

    Nov 30, 2011
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    What about this?

    http://www.ebay.co.uk/itm/DC-DC-Con...mponents_Supplies_ET&var=&hash=item82668da120
     
  17. wayneh

    Expert

    Sep 9, 2010
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    Can't comment on the actual unit, but the specs are more than adequate. Nice to have those protections built in.
     
  18. madlan

    Thread Starter New Member

    Nov 30, 2011
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    Cool, thanks for your help - I'll let you know how it goes!
     
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