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Wireless video intercom system



Market outlook

	The mainstream of development of intelligent building has flourished 
around the world and has become the twenty-first Century building industry. 
In recent years, with the popularization of computer and
The development of information industry, people's living environment of continuous
 improvement, will also "intelligent" the introduction of the construction of 
residential district and the family. Intelligent Community
And intelligent residence in twentieth Century 80 time metaphase originated in the
 America, and got a rapid development in America. Following the American, Japan,
 Europe, Southeast Asia And other countries and regions also got rapid development.
 In our country, the intelligent community and intelligent residential development 
in recent years together, and the speed of development is veryFast. Intelligent 
community and residential is along with the rapid development
 of modern science and technology, especially computer technology, communication 
technology, network technology, information technology
Technology, automation control technology, office automation technology 
popularization and application and development of the. Intelligent community 
and residential is various and information in the family
The communication equipment, household appliances and home security device is 
connected to a family intelligent system for centralized or ISO through family bus 
technologyTransaction monitoring, control and management of the family's harmony and 
coordination, and maintain the family facilities and environment of device. 
The construction of intelligent community and intelligent residential

The main purpose is to improve the quality of living of people, with a wide range
 of information and safe, comfortable, convenient, energy-saving, health, 
entertainment and living environment for the people.





Wireless visible talkback doorbell system is a new generation of electronic security systems, security device of modern garden, villa, villas ideal. Family

In room, see the image, voice intercom through the screen, remote understanding outside, accurately judge the visitor's identity, decide whether or not to open the door.

To be the support of family, personal and property safety.


 He could provide the kind of help for your life?


Video intercom: guests are coming, pressed the doorbell, the free intercom calls clear voice, as before;

Outdoor surveillance: the door has a strange sound, touch, is very clear, safe and secure;

Remote unlock: family home late; outside cold weather; do not want in bed together; do not want to get up in front of the computer; touch, come to be seen, automatically unlock;

Photo archive: the owner was not at home, a visitor. Just come to tap the doorbell, will automatically take pictures stored, the owner came back after freedom query. Miss any important meeting;

Tamper alarm: If someone sabotage door machine, indoor unit and outdoor unit will alarm.



Working principle


Working principle diagram of the visual intercom doorbell indoor extension as shown in figure 1. Schematic diagram and the diagram similar outdoor extension. The figure on the MCU AT89C2051 as the system control core, with call detection module, hang up detection module, video display and control module, unlocking and audio signal input / control module, an audio signal input amplifier module, the audio output signal preamplifier module and keys.



图1  Working principle diagram of indoor extension


When the doorbell rang the doorbell switch signal of visitors came to call the master, AT89C2051 P1.7 feet through the call detection module detects the doorbell call signal, the P1.4 pin output open the video display control signal to the video display and control module; the P1.6 output allows a call control signal to the audio control module, at the same time the 30s timing. If the owner is not at home or by identifying the display CRT display visitors decided not to meet, then 30s AT89C2051 through P1.4 and P1.6 pins are respectively output close video display signal and call barring signal; if the owner decided to receiving visitors, is off hook. AT89C2051 through the P1.5 pin has been detected off hook, terminates the 30s timing. The owner of the voice audio signal through the preamplifier module after amplification by CN, pin 4 of the AIO line to the door outdoor machine for visitors obedient, voice audio input signal and the visitor through the amplifying module from the AIO line to remove the amplified and sent Headset sound, complete the conversation action. The master asked visitors by phone and observe the expression from the display, further ascertain the visitor's identity and intention, to ascertain the host after press the unlock button "UNLOCK", AT89C2051 the unlocking signal P1.6 output via the AIO line to the gate of an outdoor machine, an electric control anti-theft door lock of the electromagnet, the door was opened. The guests at the door, burglarproof door by door closers role closed again. Master hook, AT89C2051 through the P1.5 pin has been detected by P1.4 and P1.6 hook, feet are respectively output close video display signal and call barring signal recovery, the bell state. In addition, the owner can also by active monitoring key "MORNITOR", to open the display to show visitors or view the case outside the door.

The system is a wireless conditions, use of microcontroller programming, duplex talkback technology, a camera and a wireless visual intercom intelligent system for video display technology and design. The system adopts the hybrid technology, the digital voice, video simulation, is a future full digital wireless visual intercom doorbell system transition. Video signal simulation for wireless transmission; audio signal and control signal to the wireless digital transmission, so its working principle is to separately from the analog and digital channels to explain.

The first is the analog transmission. This road is the video signal transmission, one-way transmission. In the outdoor, video signal through the acquisition and processing of the camera, to the video input RF module, RF module is transmitted in the interior, the RF receiving module of the video analog signal receiving, then receiving module from the RF video output is sent to the display screen, display the image.

The other way is the way digital transmission. Signal which is a digital transmission of audio signal and the control signal, are bidirectional transmission. In the interior, analog voice signal processing chip voice is converted into digital signal and control operation through the microcontroller is converted into a corresponding control signal (surveillance, hang up and unlocking signal), after processing and packaging, and then spread to the wireless digital transmission module, transmitted by the antenna module. In the outdoor, another wireless digital transmission module receives the digital signal, and then unpack and processing, and then the audio signal and the control signal to the speech chip and a single chip microcomputer, the audio signal after the voice chip is transmitted to the loudspeaker, control signal through the single chip to control the coordination of the various parts processing. Another direction (from outdoor to indoor) audio signal and control signal (call sign) is in a similar way to send and receive.