There are many versions of these cameras available so make sure you
know what you are ordering if you don't want to be disappointed. The
three units I had a chance to play with were pretty basic. More
expensive versions have features that I would certainly recommend. These
cameras had inexpensive CMOS sensors which are ok if there is adequate
lighting. Lighting was ok in rooms with a large window during the
daytime and in my very well lit workshop, but at night lighting in most
of my house was insufficient to provide a usable picture. Other than for
very specific uses, I would only consider cameras with CCD sensors which
are more sensitive. Another big consideration is adequate automatic
light control (ALC) to handle bright outdoor daytime lighting
conditions. Many of these inexpensive cameras appear to only be designed
to accommodate room lighting levels but this is seldom mentioned in
advertisements. Only one of these three cameras was usable in full
outdoor lighting.
The receivers required frequent fine tuning, especially after first
being turned on. The cameras had very simple transmitters with no
frequency control and drifted with temperature and battery voltage. And
the receivers had no automatic frequency control so they also drifted
due to, in addition to other things, a variable tuning voltage derived
from the temperature dependent 5 volt regulator. Better receivers
are available that have automatic frequency control. Best would be units
using FM modulation so look for cameras with receivers that feature,
usually four, 2.4 GHz switch selectable channels. I have limited
experience with everything available, but this should at least get you a
FM unit. Whether units have automatic frequency control or are crystal
controlled is next to impossible to determine without ordering and
actually examining them. Radio Shack used to sell 4 channel Wavecom 2.4
GHz FM Video Sender units that were known to have a crystal controlled
PLL circuit. However Radio Shack now sells it's own brand of identical
looking video sender with only a simple free running voltage controlled
oscillator with channel selection done by simply selecting different
resistors in a voltage divider circuit. X10.com used to also sell
Wavecom Video Sender units and the advantages of 2.4 GHz FM video
transmission. But now I see nothing about Wavecom or FM on their web
site which provides no useful information about the units they sell
other than they operate on 2.4 GHz. I was asked recently for my comments
on X10 equipment, but until someone leaves me some X10 cameras and
receivers for a few days to work with, what X10.com now provides is
anyone's guess. I did see one of their cameras advertised as having a
CMOS sensor and suspect that they all are probably less expensive CMOS
cameras.
As for the units pictured here, I did find one easily corrected
problem. I didn't lie when I said that the B&W and Color camera
receivers are the same, but they were not the same when I
first received them. The B&W cameras receiver was labelled 9 volt
and worked fine but the color cameras receiver was labelled 12 volt and
generated hum bars in the picture when operated from it's wall-wart.
Upon first inspection, the receivers appeared identical but looking
closer, the 12 volt receiver had a 20 Ω resistor, rather than a
diode, in series with the DC input and a 0.51 Ω resistor connected
to the 5 volt regulator input. The 0.51 Ω resistor provides 'fuse'
protection and the 20 Ω resistor reduces the regulator's input
voltage and therefore the amount of heat generated by the regulator.
However, 20 Ω is too large a value, especially for a resistor not
required. The resistor does nothing to reduce total receiver power
dissipation and the regulator has no problem dissipating heat without
the resistor.
