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

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.

 

"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

 

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

 

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

 

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

Good Luck!
Rich

 

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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"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

 

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.

 

----- 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.

 

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

 

"Jason SO"

** So what ??

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




........... Phil

 

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"

 

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

 

Thanks for the very detailed response Don - appreciate it.

Jason.

 

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

 

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.