On Wed, 21 Jun 2017 00:11:12 -0400, Frank Krygowski
wrote:

On 6/20/2017 10:49 PM, Jeff Liebermann wrote:
On Tue, 20 Jun 2017 11:27:27 -0400, Frank Krygowski
wrote:

Motion-activated lights indoors would make that surveillance camera a
lot more useful!

Not really. The problem with aiming a motion activated surveillance
camera through a window is that everyone that passes by sets off the
motion detector.

What I had in mind was a motion detector controlling a light, not
(necessarily) controlling the camera.

Ummm... if the shop is dark, how is the camera going to see the
burglar so that the motion detector will work? Either the camera runs
on infrared, which produces some rather low resolution b&w pictures,
or it runs on something else, like window breakage detector, RF
doppler detector, or perhaps a trip wire.

Most cameras and DVR's have a nifty feature. In low light, the
cameras switch from color to b&w, where they are more sensitive. The
motion detector actually works better in b&w. If motion is detected,
it turns on the light and everything is now in color. Just one
problem. It takes about 5 seconds to switch from b&w to color. Longer
to go the other direction, but that's not important here. What
happens is during that 5 seconds, the DVR sees a washed out image
caused by too much light and a sensitive b&w camera mode. When the
color finally comes on, it takes a while for the auto-aperture and
auto-focus to kick in. My guess(tm) is loose another 2 seconds. Seven
seconds is a long time for catching a smash and grab burglar.

The idea is to illuminate the
face of someone coming into the shop. Recording that illuminated image
is a separate issue.

I setup one store with a cheap conventional digital camera and a
strobe. The camera was in machine gun mode taking about 1 frame per
second. The strobe did a much better job of catching a photo of the
burglar, but also was great for temporarily blinding the burglar. In
two out of 4 attempted smash and grab burglaries, the thief was so
startled that he ran away empty handed. This would have been an ideal
scheme, except there's a problem. False triggering of the motion
detector just wastes some bytes on an SD card or hard disk in the DVR.
No problem there. However, if the flash goes off during business
hours, or zaps a passerby through the storefront window, it's a
problem. The big worry is that some passerby will do a slip and fall
act, claiming that they were flash blinded by the camera system.

Full disclosu I don't normally do security camera systems. One of
my friends works for a security company that offers camera
installation and monitoring. He was clueless about cameras, so he
asked my help, resulting in the clueless helping the clueless. We
proceeded to repeat all the basic mistakes, until we found someone
with many years of experience, who offered to educate us in trade for
me fixing his computer nightmare and a few goodies. We both learned
quite a bit and discovered that many of the cheap DVR's don't work
very well. For example, one such device can feed video back to a
computer via the internet. Nice feature, but if while you're watching
the store, the recorded video turns to low resolution crap due to
insufficient CPU horsepower. All of the smartphone apps I tried have
bugs or are useless. One took so long to boot up, that if there were
a power glitch, the burglary would be over before the DVR started
recording. I got to play with some rather high priced DVR's and soon
discovered the difference between cheap junk from eBay and overpriced
quality equipment. I put an end to my security camera sideline about
2 years ago, when I ran into medical issues that made running cables a
bit of a risk.

4:40AM and I can't sleep. My time share cat and the resident mouse
have made some kind of non-aggression pact. The mouse gnaws on
something in the wall, while the cat does nothing.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558