Intelligent Home Security System

Votes: 1
Views: 4591

Knock, knock, knock! As a homeowner, I get visits from home security companies. As a father and a husband, I want to do everything within my power to ensure the safety of my family. However, current commercially available home security systems are rather cost-ineffective and just very passive electronics. Service normally requires a multi-year contract with costly monthly payments, and even then may not provide any protection in the case of an intruder (more on this below). Utilizing inexpensive hardware and advances in pattern recognition software algorithms, I propose a family of intelligent home security systems as follows.

The simplest device is an intelligent appliance timer that automatically learns the daily routines of the owner. It has a relay to switch power, microphone to measure sound level, photodiode to measure light level, real time clock with backup batteries, and microcontroller with flash memory. Analog circuitry will register when appliances like lamps or TVs are turned on and off. The microcontroller timestamps those events and records them in memory. When switched to “Away” mode it activates the appliances according to the history of recorded events. What’s novel about this device is: (i) it requires no programming from the user, and (ii) it mimics very realistically the activities of an occupied home.

Taking the idea one step further, one can make an intelligent home security robot. With almost the same hardware as above but more sophisticated software, we have the next generation security device. It can take the form of a wall décor, paperweight, or plug-in night light to be discreet. Inside will be a microphone, photodiode, infrared sensor, siren alarm, wired and wireless telephone dialer, real time clock, memory, and DSP (digital signal processor). The device will learn to recognize the family members’ voices, light and sound/noise levels, infrared (indicator of warm bodies), analyze the data, and react appropriately. If you are at home at 6pm and a robber posing as a salesperson forced his way into your home and demand your money, the robot would recognize the strange noise and voice and elevated sound levels and notify the police (current systems would provide no protection in case of an intruder when you are home and the system is disarmed). Similarly, it will react to infrared activities at 2am, sounds of glass breakage, door opening, gun shots and many other distress sounds via sound recognition software and not requiring a sensor at every door or window.

The manufacturing of the device will be inexpensive. It requires no special hardware or expensive sensors. There will be a one-time software development cost to program the DSP with pattern recognition and control software. With bulk volume production this cost is also reasonable.

The market potential is great for this type of devices. Tens of millions of homeowners will have a more cost-effective and even safer solution to home security; one that brilliantly integrates common electronic hardware with well studied software algorithms to achieve the greatest benefits in providing security for individual families.


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  • Name:
    Thientu Ho
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    Multisim, ModelSim, MATLAB
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    Oracle/Agile PLM
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    hobby electronics, reading, tennis, soccer
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  • Thientu is inspired by:
    The joy of designing innovative electronic circuits, the pride of making reliable technology products, and my personal aspiration to excellence in electronic design.
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    PCB, sensors, electronics
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