THE STAR TUESDAY November 26 1996 

                  IN-TECH / 47 
By WEE CHUN CHUAN

   Businessman Jimmy Tok expected his expensive home security system to protect his property and give him peace of mind. one day, after coming home from dinner, he discovered how wrong he was.
   Apparently, some not-so- sophisticated crooks managed to beat his sophisticated home security system the old fashioned way - by using brute force.
   This prompted Tok, 26, and business partner K.Y. Cheong to come up with a better alternative: they decided to design their own home security system, complete with a PC-based controller.
   Named Sentinel Pro, the system is jointly written by the two in Pascal and assembly language, and utilise custom-made peripherals and equipment.
   Touted as "the next generation in computerised security and automation system," Sentinel Pro boasts a few unique features.
   Exactly what is Sentinel Pro? its creators describe it as a 7+1 alarm system. That's seven different monitored zones within the house, plus one smoke detector. Because it uses a PC, the system is flexible enough to allow customisation of control parameters within each zone.
   For example, the owner can program the kitchen lights to come on every night at 1am and turn off at 4am, creating the illusion that somebody is still awake. Chances are, your average weekend thief will not even attempt a break-in if they think somebody's home.
   Furthermore, Sentinel Pro allow a maximum of 16 devices to be connected and controlled in this manner, utilising a 255-channel broadcast spectrum. This translates into a lot of devices that may be controlled.
   Some people might be a little apprehensive about leaving a PC on 24 hours a day, seven days a week, all year  around. 
    However, since the software controlling Sentinel Pro is small enough to reside in the computer's memory with no need to read or write to files on the hard disk, unnecessary hardware such as the hard disk and monitor are optional.
   This reduces energy consumption as well as wear and tear on the computer system, says Tok.
  
Security with
a local twist

                                                  The Sentinel Pro at work
   Insta-Home automation
   You thought that this was only an alarm system? Well, think again. Due to the architecture of the system, Sentinel Pro also arts as a home automation device; it is possible for the home-owner to control many functions simply by  using a wireless telephone handset.
   Think about it: since anything connected to the system's special received powerpoints can be wireless controlled via the computer, it wouldn't be all that hard to make the computer receive its own instructions over the airwaves.
   In fact, Sentinel Pro is fully controllable using nothing more sophisticated than a tone phone.
   Theoretically, any phone which generates a tone(as opposed to the old pulse type) should be able to send instructions to the computer. 
   Sentinel Pro ships with a wireless tone phone, making it very easy (not to mention convenient) to, say, turn on the radio while you're erm, inconvenienced in the bathroom.
   As far as home alarms go, this one is slightly more intelligent than the average offering on the market. Some intelligence is built into the controlling program to account for natural phenomena.
   Things like the cat trying to get to its favourite haunt on your roof, vibrations caused by thunder or wind-related impact do not set off Sentinel Pro. Since the device is computer-controlled, a lot more flexibility has been built into the alarm.
   Most alarms work on the principle of interpreting signals received through sensors and administering the appropriate responses.
   For example, if an impact sensor detects something within its field of operations, it will send a very simple voltage signal to a central controller.
   Depending on the sophistication of the system, this signal might be a simple on/off type; or on more intelligent systems, its strength might be directly proportional to the strength of the disturbance (the harder the impact, the larger the voltage transmitted back to the controller).
   The central controller will then interpret the signal coming in and decide if a break-in is being attempted. Should the controller deduce that a break-in is in progress, it will then activate whatever countermeasures are available (sirens, lights, etc).
   Usually the interpretation of the signal works around certain thresholds and these parameters are "hard-wired" into the controller unit. This means that you cannot program the device to adjust to your lifestyle (not much, anyway); instead, you and your lifestyle must adjust to the device.
    With a computer, this is no longer the case - threshold parameters such as acceptable impact detection (due to that darn cat) can be programmed into Sentinel Pro's reference tables, helping it differentiate between a friendly cat and an unfriendly cat-burglar.

Configuring the Sentinel Pro is a piece of cake.
   The sensors which come together with Sentinel Pro are what you would typically find in an alarm system: sensors to detect proximity, movement, passive infrared and impact. the operating thresholds, as mentioned earlier, can all be configured through the computer.
Sentinel Pro with all the bells and whistles for home security consists of:
  • An Intel 286-based PC with a 2400 baud modem, 16-bit sound card, monitor and 1MB of RAM;
  • A PCM transmitter;
  • A tone decoder interface card;
  • An Uninterruptible Power Supply (UPS) for the computer;
  • A second-stage built-in battery backup for the computer;
  • One passive infrared sensor;
  • 10 normal magnetic reed switches;
  • 10 vibration/impact sensors;
  • Two concealed magnetic reed switches;
  • One outdoor siren;
  • One indoor siren;
  • One strobe light;
  • One PCM receiver unit; and
  • One cordless tone telephone.
   The above configuration is designed to cater to the security demands of a typical bungalow-sized house; of course, the configurations are subject to change depending on the actual house layout.
   According to Tok, the above setup will cost approximately RM4,988. Tok says the system also comes in scaled-down versions: Mini Sentinel for RM299, and Sentinel 8 at RM1,688.
   Enquiries: PC Sentry Sdn Bhd, (03) 732-1073/5.
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