Telephones and mobile phones are one of the most commonly used communication tools in modern life. If we can combine the use of telephone network and electronic technology, wireless communication, computer technology and other technologies, we can easily go out and go out. Master the situation at home. Therefore, if a convenient and practical home automation and anti-theft security system can be established, it can provide a way to easily manage the home environment, achieve anti-theft security and save energy.
This study uses the public telephone network to connect to a single chip (EM78P451P) via a multi-frequency receiving IC (KT3170), connect it to the monitoring sensor of the home appliance and door and window through a single-chip drive external circuit, and then use the EEPROM (93C66) memory to set the phone and The mobile phone number is transmitted via the telephone network to achieve a two-way monitoring system for controlling home appliances and anti-theft security.
1 System Planning and Design Figure 1 shows the hardware architecture of the telephone network used in home appliance control and anti-theft monitoring system. It mainly uses a single-chip microcontroller as the central processing module, and cooperates with the public telephone network system to realize the functions of home appliance load control and anti-theft monitoring.
1.1 Hardware Structure Most of the functions of the appliance control and anti-theft monitoring system are completed in the central processing module. The central processing module is actually a microprocessor, and the functions of the system are designed in assembly language.
The 4×4 keyboard is used as an input channel for home appliance control and anti-theft monitoring system, such as setting or browsing of phone numbers or mobile phone numbers. LCD display for displaying the set phone number or mobile phone number. Twenty groups of telephone numbers to be notified can be stored using the EEP-ROM (93C66). The telephone automatic dialing hardware architecture is shown in Figure 2.
The signal situation of the telephone line is as follows:
1 When the telephone line is in the waiting state, the voltage across it is 45 V to 55 V.
2 When ringing, the signal is a sine wave with a voltage of 100 V, 20 Hz.
3 When picking up the phone, the voltage across it is 5 V.
4 After the phone is connected, when the button on the phone is pressed, each button will generate a DTMF signal, which is transmitted on the phone online to achieve the purpose of home appliance control, and the keystroke number corresponds to the signal output frequency value.
Before dialing, the central processing module must detect if the telephone line is occupied. If no one is used, a high level signal is transmitted, and the controller is controlled to be ON by the level control switch (ie, the telephone is turned on, that is, the telephone tube is picked up). When the data is being transmitted and someone picks up the phone, the central processing module will detect that the line is occupied. At this time, the transmitted data will be interfered. The central processing module waits for 10 seconds and then dials again. When the phone rings, the central processing module will transmit a high-potential signal. After the level-controlled converter, the level-controlled converter turns ON and starts to receive 16 data and automatically hangs up the phone. The hardware architecture process is as follows: Figure 3 shows.
The voice system can pre-record the load action situation. When the controlled load (door, window, safe...) sensor senses, the CPU will go to the EEPROM set phone number or mobile phone number and dial out through the public telephone network. When the controlled phone or mobile phone is connected, the mobile phone can display the home phone number and the number of rings, and you can know that there is a situation in the home, or you can connect with the home phone. Then you can start the voice module of the system to know the details of the home. The hardware architecture flow is shown in Figure 4.
1.2 Software Module This system is equipped with telephone network to plan home appliance control and anti-theft monitoring system. This system includes four items: telephone receiving data, telephone automatic dialing, keyboard setting data (telephone or mobile phone number), and voice system.
The central processing module uses the scanning method to determine whether to accept the interrupt and the interrupt priority. The hardware architecture flow chart is shown in FIG. 5.
(1) When receiving data by telephone, the data is first set to receive a total of 16 data. When the phone rings, after 0.5 seconds, the central processing module will automatically connect the phone, receive 16 data, and judge whether it is The confirmation code has been set. If not, the central processing module will not process the signal and automatically hang up the call. If yes, the code will be activated according to the command, such as all load shutdown commands, setting the lamp action command, setting the power. Five kinds of controls, such as rice cooker operation command, setting electric fan operation command, and setting air conditioner operation command.
(2) The phone automatically dials the system. Before the phone is automatically dialed, it must first determine whether the phone is busy. If it is busy, the CPU will wait for a period of time. If it is idle, it will immediately connect the phone and automatically set it up. The phone number is dialed out, and then the data is transmitted. After 20 seconds of ringing, the phone is automatically cut off, and then it is judged whether all the set phone numbers are dialed.
(3) Keyboard scanning mode The microprocessor scans the keyboard and judges whether it is pressed to the B or C button. When the B button is pressed, it indicates “set the phone or mobile numberâ€, when the C button is pressed. It means "Browse the set phone number or mobile number".
1Set the phone or mobile number method:
Press the "B" key on the keyboard first. You can enter a phone number (8 yards) or a mobile phone (10 yards). Confirm that the phone or mobile number is correct. Press the “B†button again to enter the phone or mobile number into the 93C66 memory, and the data will not disappear due to power failure.
2 Browse the set phone or mobile number:
Press the “C†key on the keyboard to display the data on the LCD. The front part has the serial number (NO: XX) and then the phone number or mobile number. Press the “C†button again to confirm the next phone number or mobile number.
(4) Voice system When the voice system is activated, the CPU will read the load action data of the voice IC through the public telephone network and judge whether it is more than 20 seconds. If it exceeds 20 seconds, the phone will be cut off automatically.
2 Conclusion This system has developed the basic equipment based on telephone network remote control appliance and anti-theft monitoring system, including load controlled unit and telephone, mobile phone and other equipment. The actual test shows that the receiving and action of the controlled load can operate normally, achieve the expected effect, and have high use value.
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