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TELECAM CCTV CAMERA SYSTEM

 

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WHAT OUR EXPERTS SAY...

Over the past five years advances in video camera technology have had a tremendous impact on the security and surveillance industry, that have been felt far beyond its traditional bounds. One development in particular -- the sub-miniature ‘board’ camera -- has created several new and thriving niche markets for covert and concealed cameras, and is helping to ‘domesticate’ CCTV.

 

Tiny, low-cost board cameras, where the CCD imaging chip, control electronics and usually a ‘pin-hole’ lens are integrated together onto one postage-stamp sized circuit board, are now being produced in vast numbers in the Far East. They’re simple to use, requiring only a low-voltage DC supply, and a connection to the composite video input of any video monitor or TV. Suggestions that that cameras can be purchased in bulk, direct from the manufacturers, for less than £30 each, are probably not far from the truth!

 

One thing is clear though, they’re responsible for changing public perceptions, that CCTV is a complex and expensive technology, used more or less exclusively by commercial, industrial and governmental organisations. Now low-cost door observation systems, some packaged for home installation, are being sold in DIY ‘sheds’, through mail order advertisements, and even featured on the QVC satellite home shopping channel. Whilst some installers and security specialists may regard these products as a threat to their business, others see them as an exciting  new opportunity, helping them to reach the much broader, and so far, largely un-tapped consumer market.

 

Most of the systems that have appeared so far follow a fairly predictable pattern. They’re being pitched at security-conscious householders, enabling them to see who is at their front door, on their living-room televisions. The cameras included in these packages come in a variety of guises, styled to look like miniature surveillance cameras, or hidden away, inside PIR detectors, door-bell boxes, porch lights or anonymous-looking black-plastic domes.

 

The Viewmate Telecam System, (rrp £129.99) which is the subject of this month’s Bench Test,  is slightly different. Billed somewhat inaccurately as the worlds ‘smallest’ video camera (Matshushita might have something to say about that...), it is nevertheless remarkably compact, so small and inconspicuous in fact, that virtually no attempt has been made to disguise it, or make it look like a security camera. The housing is a purely functional encapsulation, protecting the electronics and optics from mechanical shock and the weather. The rest of the system has a familiar ring to it, though. The 15 metre cable, that carries both power plus video and audio signals -- to and from the camera -- connects to a small black box interface module. This contains an RF modulator, and power supply regulator.

 

The Viewmate box, which is a little thicker than a pack of 20 cigarettes, has four sockets. Two of them are standard co-axial connectors, for the aerial lead bypass to the TV. There’s a 6-pin mini DIN socket for the camera lead, and a DC power socket, for the plug-in mains adaptor module.

 

Normally the interface unit connects between the aerial downlead and the TV (and VCR, if one is included in the aerial chain). The output on our sample was factory set to UHF channel 36. This will almost certainly require re-adjustment as that clashes with the default channel on a lot of VCRs and some satellite tuners, which in turn can cause problems in areas where there are Channel 5 broadcasts. The RF output is variable, between channels 29 to 39; the adjusting screw can be accessed through a hole in the casing. The modulator (an ALPS module, similar to those used on VCRs and satellite receivers etc.), also has a simple two-bar tuning pattern generator. This is enabled from a small switch, in a recess next to the camera socket.

 

The camera module is incredibly small, measuring approximately 25 x 25 x 18mm, with the lens barrel adding a further 15mm to the depth. To put that into perspective, the profile just a little larger than a fifty-pence piece, it will fit snugly inside a matchbox! The housing is completely sealed, the only opening is for the electret microphone, on the underside of the module. There are no controls (accessible from the outside), other than a simple twist-focus adjustment. Te focusing range is from just a few millimetres in front of the lens, to infinity.

 

The lens is a 5-element, wide-angle type, giving a 45 degree angle of view. The image sensor is an IR responsive VLSI CMOS type, producing a monochrome image with a claimed low-light sensitivity of 1 lux. Gain control and electronic shuttering are both fully automatic.

 

There are two mounting options, based on a simple bracket, held in place by two screws; this comes with  interchangeable straight or right-angle ball fittings, that clip into a moulded socket on the back of the camera. They’re a good tight fit, allowing the camera to be easily positioned.  However, this fitting method is far from secure, and the camera easily detaches from its mount, with just a slight tug. Fortunately, being small and unobtrusive, the camera is easily hidden and can be discretely positioned above eye-level, where it will almost certainly remain unnoticed by most casual observers.

 

INSTALLATION

Despite the fact that Telecam has been designed for DIY installation, the instruction leaflet glosses over the practicalities of fitting the mounting bracket and camera to wood or brickwork, drilling holes through brickwork or masonry, running and securing cables. Clearly some expertise is required, a useful cue for installers, to offer their expert services, to customers put off fitting the system themselves.  There’s helpful diagrams, showing how the system connects together. It also mentions the fact that the cable can be extended, to up to 50 metres, though the suggestion that ‘a four-core screened cable with mini DIN connectors’ is required, will mean little to most end-users; a pin-out diagram for the connector would have been useful. There’s a fair amount of information, about how to tune in the TV, some helpful hints and tips, for aligning the camera, and a troubleshooting guide, but with such a simple system, and the almost complete lack of user adjustments , it doesn’t stray much beyond the plainly obvious checks, that it is switched on, and everything is plugged in.

 

PERFORMANCE

Comparisons with other types of video camera are difficult as this system uses RF modulation, rather than a straightforward composite video feed to the monitor, so the image can be viewed on a normal living-room television. However, using our standard test procedures, the camera managed to resolve a little over 350 lines, using the RF connection, which is about par for the course. However, noise levels were rather high, giving the image a fairly grainy appearance, that no amount of re-tuning of the modulator or TV could resolve. This is almost certainly due to the modulator, as the off-camera signal is reasonably clean. If our sample is typical increasing the length of the cable much beyond the 15 metres supplied would almost certainly lead to a rapid deterioration in image quality.

 

The dynamic range is average, the exposure system, optics and gamma correction appear to have been  optimised for low-light conditions. Low-light sensitivity is fair and it will produce a useable image with a normal porch light. The lens produces some barrelling at the edges of the image, though this is a reasonable trade-off, given the wide angle of view.

 

Audio from the built-in microphone is crisp, and picks up incidental sounds within a metre or so of the camera, with no difficulty. The output level appears to be on the low side, though, and on our sample the TV volume control has to be set somewhat higher than normal broadcast channel levels.

 

A slight intermittency on our test camera resulted in the image and sound being lost. This was eventually traced back to the camera, and twisting the cable slightly, where it enters the camera housing, restored the signal. Since both picture and sound disappeared together it’s likely the fault lay with the DC supply connection.

 

OVERALL ASSESSMENT

It’s difficult not to be impressed by the small size of the camera, it’s performance less so, and we suspect the picture could and indeed should be a lot cleaner. Noise levels on our sample were bordering on the unacceptable. However, assuming that the noise and intermittency problems are confined to our sample, it’s possible to see that the system can work very well indeed. We’re a little sceptical about its DIY credentials, though that could be resolved with better instructions, and maybe a few little extras, even something as simple as a pack of cable clips would help. The connecting cable could do with being a little longer, 20 metres would be a good starting point. However, in the end it’s the tiny camera and attractive price that sets this system apart form the crowd; it should help spread the word and bring the benefits of CCTV to a much wider domestic market.

 

PRODUCT ASSESSMENT

Design and design features              ****

Circuitry and components                  **

Ease of installation and wiring    ***   

Range and variety of functions            **     

Accompanying instructions                   **                                

Technical advice and backup            ***     

Value for money                         ****                           

 

 

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Ó R.Maybury 1997 1202

 


 

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