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Need advice re night vision for 2.4GHz CMOS wireless colour camera

Discussion in 'Electronic Basics' started by Jason S, Feb 17, 2006.

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  1. Jason S

    Jason S Guest

    Not sure if anyone can answer this, but I recently bought a *2.4GHz Mini
    Wireless Pinhole CMOS Colour Cemera* (Jaycar CAT QC-3580). Works great,
    only I later realised I needed a IR spotlight so that it will work at night
    as well. By the way, I can't send the camera back now because it is against
    their "Strict 7-day Return Policy" =(.
    Anyway, so I went and bought that - an IR spotlight! Jaycar CAT QC-3650.
    It says it has an effective range of 5 metres. Tested it in the dark, and
    found it only works well within 1 metre!!! You can see the IR LED's glow
    slightly red which is normal I suppose, but the thing is totally useless.
    Mind you, it has *18* IR LED's! What do you think? Do you think I need a
    much more powerful one? If you're thinking "Yes", I don't understand,
    because some cameras I've seen have less than 12 of these built around the
    camera lens, and this one has 18. I haven't really come across many of
    these standalone IR spotlights around, but if there are different/more
    powerful ones around, please let me know.

    Thanks in advance

    Jason.
     
  2. Phil Allison

    Phil Allison Guest

    "Jason S"

    ** You should direct you query to Jaycar - they sold the damn things.

    A brief scan on the catalogue reveals that for good IR performance a CCD
    camera is needed - preferably a B&W one.

    There is a *clear warning* that the AA-0290 IR spotlight is *not* useful
    with CMOS colour cameras - so very likely also is the one you bought.




    ........ Phil
     
  3. Pooh Bear

    Pooh Bear Guest

    There is no way that an IR spotlight can be given an 'effective range' since it
    depends on the *camera sensitivity*.

    I'd say that was pretty obvious.

    It seems that Jaycar are ( though over-simplistic descriptions ) falsely
    representing their products. Despite the no-retunrs policy I'd think you have a
    case under consumer law that the goods were misrepresented. Take it up with
    Jaycar first and see if you can sort it out.

    Colour cameras aren't as good for night use as B&W btw.

    Graham
     
  4. Jason S

    Jason S Guest

    Good point. May consider a B&W CCD for better night-vision instead then, as
    Phil Allison has already suggested. Thanks for your input.
     
  5. Rich Grise

    Rich Grise Guest

    I think you should take the IR filter off the front of your camera lens.

    Good Luck!
    Rich
     

  6. A colour camera will have three sensors optimized to respond to red,
    green, and blue light - I'd expect it to be pretty much blind to IR.

    I don't think you've got any grounds for complaint.



    --
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    peterbb4 (at) interchange.ubc.ca
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  7. Phil Allison

    Phil Allison Guest

    "Peter Bennett"

    ** Only one chip is used in all but the most expensive cameras.

    This trick used to get colour.

    http://en.wikipedia.org/wiki/Bayer_filter





    .......... Phil
     
  8. Don Bruder

    Don Bruder Guest

    For consumer-level gear, that tech went out quite a while ago in
    technology terms. Single-sensor chips that do color have been the norm
    for years. To the best of my knowing, the only current cameras using the
    three-sensor method are *WAY* out of reach of "Joe Consumer". Their main
    users are folks like Lucas and Spielberg - People who have the budget to
    spend amounts that have 5 or more figures to the left of the decimal
    point on a camera. If the Jaycar unit he's got is similar to the
    "XCam-2" units I've got (I'd expect they're so close to identical that
    the differences don't matter) then it's DEFINITELY a single-sensor unit.
    Not likely - Most (if not all) consumer-grade sensors are more sensitve
    to IR than anything else, and the IR sensitivity, combined with IR
    focussing slightly differently than visible light, results in a "fogged"
    image, so some camera makers drop in an IR-cut filter between aperture
    and sensor. But that isn't quite the same thing as the sensor being
    blind to IR.
    If his camera is the type with an IR filter, that's probably true - It's
    *DESIGNED* to not shoot IR worth diddly. If it's one of the unusual ones
    that doesn't, he's got a garbage illuminator and a perfectly legit gripe.

    Jason -
    You may very well need to take your camera apart and remove the IR
    filter - Often a clear disk or sheet mounted somewhere between the
    aperture and the sensor, which will be easy to remove, but could be a
    coating on either the lens or the sensor itself, in which case, unless
    you can figure out a solvent that will take it off without destroying
    the underlying surface (lots of luck with that...) there's not much you
    can do but put the camera back together and live with it as-is.

    18 LEDs isn't that potent of an illuminator - The ones I've seen that do
    a good job have 50 or more, and the top-of-the-line LED-based IR
    illuminators often have more than 200 LEDs.

    Try this: Point the illuminator directly at the camera from a couple
    feet away. If the image "flares out" (like what happens if you point it
    at the sun, a spotlight, or similar high-intensity light source), then
    it probably isn't the camera, but the illuminator. If it doesn't
    "flare", then either the illuminator isn't working, or the camera has an
    IR-cut filter in it. If you can see a dim red glow from the illuminator,
    then it's definitely working, and if the image doesn't flare when you
    point it at the camera, the camera is almost certainly fitted with an
    IR-cut filter.

    If you find that it "flares", you might have luck with "dialing down" an
    incandescent lamp, like a (*NOT* LED) Mag-Light or one of those "million
    candlepower" spotlights - Put a good beefy pot inline with the power
    source and adjust it so that the filament is "choked down" to a faint
    red glow. At that point, most of the output is IR, and it should do a
    relatively decent job.

    Another method I tried that seemed to work fairly well was taking one of
    those "black" CD-Rs (The plastic is black under visible light, but to
    IR, it's as transparent as window glass is to visible light - it *HAS*
    to be in order for the IR laser in the CD drive to be able to read the
    data from it) polishing the "label" side down to the black plastic (to
    remove the label, reflective and dye layers) and then fitting it to a
    Coleman "Million Candlepower" spotlight in front of the original glass
    lens. Leaving the center hole open will give you a handy way of knowing
    exactly where the beam is hitting, or you can tape a nickel over the
    hole if you're trying to do "I can see you, but you can't see me" type
    work from a fixed position.

    Caveat: Don't expect crisply focused images when shooting in IR - Due to
    the wavelength difference, IR and visible light focus in different
    places. A lens/pinhole focus system built for visible light is going to
    put the focus point either ahead of or behind (Without looking it up, I
    forget which way the focus point moves, but it does indeed move) the
    plane of the sensor when used for IR, leaving the image at least
    slightly blurred if you've set the focus using a visible light image.
     
  9. Jason S

    Jason S Guest

    ----- Original Message -----
    From: "Phil Allison" <>
    Newsgroups: sci.electronics.basics
    Sent: Friday, February 17, 2006 11:05 PM
    Subject: Re: Need advice re night vision for 2.4GHz CMOS wireless colour
    camera


    No no, I bought the QC-3650 which didn't have a warning, so I went for that
    one instead. Thanks for your input.
     
  10. Jason S

    Jason S Guest

    Thanks for the reply, but because this is a mini pinhole camera, I'm not
    sure that is possible =)
     
  11. Phil Allison

    Phil Allison Guest

    "Jason SO"

    ** So what ??

    The problem is with the damn cameras - not the IR leds, dickhead.




    ........... Phil
     
  12. K `Sleep

    K `Sleep Guest

    My Sony Camcorder has a switchable function for night vision, and has a
    built-in illuminator. The illuminator "lens" seems only big enough for 1 LED
    (its only about 10mm across) but it can illuminate a entire room that is
    about 10 x 10 ft.
    Pretty amazing that!

    Kim
    "the man with a girls name, but Frankensteins body"
     
  13. Jason S

    Jason S Guest

    Yep, and they should build them into security cameras - even tiny ones like
    mine. I wonder if you can get them...... I mean, why would you need to use
    more than 20 IR LED's to light up an object if this little illuminator
    you're describing is so tiny? I don't understand that! =S
     
  14. Jason S

    Jason S Guest


    Thanks for the very detailed response Don - appreciate it.

    Jason.
     
  15. Si Ballenger

    Si Ballenger Guest

    I've never tried one, but one of those "heat" lamp bulbs might
    have a lot of IR output.
     
  16. Don Bruder

    Don Bruder Guest

    That's definitely a good IR source, but I'm not sure if they're the
    right wavelength. My suspicion is that the wavelength is going to be too
    long to be useful as an illuminator. Another drawback to them: All of my
    applications so far have been "need to run on batteries", and I haven't
    encountered a heat lamp bulb designed to run on anything other than
    wall-socket juice.
     
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