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Product Review
The “Wachit” Smart Video Motion
Detector turns an ordinary VCR/
DVD-R into a security event
recorder. A built-in learning
infrared remote is used to control
the recorder. After a simple setup procedure, all you need to do
is hook up the video cable and
position the supplied infrared
emitter in front of the recorder to
begin recording events.
“Wachit” – it turns a
By MURRAY DOWNES*
VCR into a security recorder
E
VERYONE IS FAMILIAR with the
passive infrared and microwave
sensors that are used to activate door
openers, security lights and alarm
systems. Less known is the existence
of devices that use image processing
to detect motion and trigger alarms,
recording and other actions. These are
generally referred to as Video Motion
Detection (VMD) sensors.
Whereas a PIR or microwave sensor
has a limited range, VMD sensors can
function over very long distances and
wide areas because they work from
a video camera image that could be
viewing anything from 3m to 5km
away.
Farco Technologies Limited manufacture high-end video motion detection systems that are used in red light
cameras and traffic signal controllers.
They also produce a range of low-cost
*Murray Downes is the Sales & Marketing
Manager for Farco Technologies, Ltd.
46 Silicon Chip
VMD devices that utilise high-speed
image processing technology.
The “Wachit” is a small, sturdilyhoused unit that’s connected between
a video camera and a recording device.
It comes equipped with relay outputs
and can directly control a recording
device via its inbuilt infrared remote
learning capabilities.
Farco also offer the VMD-19 module for those that wish to use VMD
technology in their own products. The
module consists of a small printed circuit board with the same footprint as
a standard 18-pin 0.6-inch wide IC. It
can be directly connected to a composite video source to detect the motion of
objects within the video signal. From
the outset, Farco designed the VMD-19
for easy integration in security cameras, VCR designs, video switchers,
quad processors, multiplexers, etc.
VCR surveillance
When integrated with a VCR, the
VMD-19 transforms it into an intel-
ligent motion-detecting surveillance
device. When motion is detected
within the video signal, the VCR automatically starts recording the scene.
Once the motion ceases, the VCR stops
recording. This avoids hours of recording of non-eventful static images.
With video motion detection, there
is no need for the additional cost
The VM-19 module consists of a
small PC board carrying a single
IC and a number of tiny surfacemounted components. The
complete assembly is the same
size as a standard 18-pin 0.6-inch
wide IC.
siliconchip.com.au
and complexity of external triggering devices. False alarms that can be
triggered by camera noise are largely
eliminated in the VMD-19.
This technology creates an ongoing
role for those VCRs that have been
made redundant by DVD players.
By incorporating Farco’s low-cost IC
into their circuit designs, electronics enthusiasts now have the means
to develop state-of-the-art security/
surveillance systems.
The VMD-19 is not just limited to
controlling video recorders and can
also be put to work in a multitude of
trigger and/or indicator applications.
Here are just a few possibilities:
• video loss detection
• security light switching
• alarm system enabling/disabling
• gate and door monitoring
• lighting control in storage and utility areas, stairwells, works of art, car
parks, freight holding areas, etc.
As well as the obvious home security applications, the VMD-19 has
also been used to trigger recording and
remote alarms for monitoring wild life
(eg, nesting sites).
For more information, contact
Murray Downes on +64 3 374 5534
siliconchip.com.au
Fig.1: this simple circuit demonstrates the capabilities of the VM-19.
The composite video signal is fed directly into pin 18. Sensitivity is
determined by the logic states of pins 12 & 13, here connected to a 2-way
DIP switch. When motion is detected in the video source, pin 14 goes
high, illuminating the LED. In an application circuit, this pin would be
used to control external recording and/or alarm equipment.
or email sales<at>farco.co.nz. You can
also write to Farco Technologies Ltd,
200 Armagh Street, Christchurch, NZ.
Product datasheets and online sales
are available from their website at
SC
www.farco.co.nz
September 2006 47
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