Date:         Sun, 28 Dec 2003 10:58:06 -0600
Reply-To:     Larry Alofs <lalofs@RCN.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Larry Alofs <lalofs@RCN.COM>
Subject:      cameras for viewing front heater fan
Content-Type: text/plain; charset=us-ascii; format=flowed

If you want to try lubricating your Vanagon's front heater fan without
removing the dash, etc. you need a reasonably small video camera.  I'll
describe what I used and another option.  For either, you will need a
monitor or TV that accepts standard NTSC video, typically thru an RCA
type jack.

The camera I used came from Allelectronics.com (item VC-360). Click on
"cameras" to see various offerings.  It's a bare board pin-hole type,
1.2 inches square for $49.  I wanted something small and cheap.  They
now have a few other cameras that may also be suitable and less trouble.
   The advantage of the "pinhole" type is that it is already focused
reasonably well at all distances.  With this camera I had to put it in a
small plastic box for protection and find a suitable power supply and
connector.  Having done that, it worked well and the resolution was
sufficient.  Since it does not have any built-in light source, I used a
tail lite bulb dangled into the air intake and manipulating it as well
as the camera and the lubricating probe was rather challenging.
   About the time I was doing all this, I found that Harbor Freight had
a small camera for $30.  I ordered one to see how well it would work,
since the price was so low.  At Harborfreight.com it is item 47546.  In
catalog 744-k it is item 47546-1rzh also at $30.  In some catalogs it is
priced at $40 instead of $30.  The advantages of this camera besides the
price are: built-in IR LED illumination, power supply included, small
weatherproof case, 80 ft of cable!.  The disadvantage of this camera is
that it uses a conventional lens which seems to be focused at infinity
and therefore produces a rather blurry image when trying to view a fan
at a distance of 6" or a foot.  After I received this camera, I pulled
off my van's grill, etc. again and stuck it in there just to see how
well it would work.  The built-in illumination was bright enough and
very convenient, but when I bought it close to the fan the image was
blurry enough that it would have been difficult to use if I hadn't
already been familiar with what I expected to see.
   I got this camera out again and played with it again today.  I found
that by holding a small cheap plastic magnifying glass against the front
of the camera, it would give sharp images of things at a distance of 6
to 12 inches.  I tried a few different lenses and it seems that
something with a focal length of 2" to 3 1/2 " would work with 2 1/2 to
3 " best.  To check the focal length of a converging lens: in a dimly
lit room let light from a window or other light source that is at least
30 ft away come thru the lens and hit a plain white surface a few inches
from the lens.  Adjust the distance between the lens and the "screen"
until you see a clear image of the window frame, etc.  The distance
between the lens and the image is approximately the focal length.
(I admit it, I'm a physics teacher.)
   Anyway, knowing what I know now, I would get the Harbor Freight
camera and tape a small magnifying glass on the front of it, but YMMV.

Have fun,
Larry A.