9-Intelligent fire alarm system based on 51 single chip microcomputer

Specific implementation functions

The system consists of 51 single-chip microcomputer + MQ-2 smoke sensor + ADC0832 analog-to-digital conversion chip + DS18B20 temperature sensor + digital tube display + button module + sound and light alarm module.

Specific functions:

1. Real-time monitoring and display of temperature and smoke concentration;

2. The smoke alarm value and temperature alarm value can be set through three buttons;

3. It can realize manual emergency alarm and manual alarm cancellation functions;

4. When the temperature exceeds the threshold, the buzzer sounds and the yellow light flashes; when the smoke exceeds the threshold, the buzzer sounds and the red light flashes;

5. Measuring range: Smoke concentration: 0-9 levels; Temperature range: 0-99 degrees.

design background

The development of intelligent fire alarm systems is changing rapidly. The development of new technologies has further expanded the application areas of fire alarm systems and provided effective means for some environments where alarm systems are not competent. my country's fire alarm has developed from nothing to something, and from something to the current intelligent. The fire alarm system has taken a faster pace in the direction of early detection, multi-sensor composite detection, and miniaturization and intelligence of detectors.

With the innovation of technology, single-chip microcomputers have been deeply applied to various fields of industrial and agricultural production and people's daily life applications. Therefore, various types of single-chip microcomputers have been developed according to the needs of society. Single-chip microcomputers are device-level computer systems. In fact, they are microcontrollers or microprocessors. Because of its complete functions, small size and low cost, it can be applied to any electronic system. Similarly, it is also widely used in the field of alarm technology, making the functions of various alarm devices more perfect and the reliability greatly improved to meet the needs of social development.

hardware design

The principle of the intelligent fire alarm system is that when the smoke concentration or temperature reaches the set value, the smoke sensor and temperature sensor sense the signal, which is processed by ADC0832 for analog-to-digital conversion and then processed by the microcontroller, and the speaker sounds an alarm. The system is divided into control circuit, detection circuit, display and alarm circuit.

software design

First, start executing the initialization subroutine. The initialization functions include setting the input and output status of the I/O port, register initialization, interrupt function, etc. Set the initial timing value to 50ms, and use IAP to write to EEPROM as the value interval. Then, set timer 0 and select mode 1. In mode 1, the working registers TH1 and TL1 of the timer are all 16 bits involved in the operation. Next, set the interrupt enable position of timer 0 to 1, turn on timer 0, turn off the buzzer, turn on the green light, and set the initial alarm value.

Schematic

The schematic diagram of this system was designed using Altium Designer19, as shown in the figure.

program

This design uses KEIL5 software to implement program design, as shown in the figure.

Simulation Implementation

This design uses protues8.7 software to implement simulation design, as shown in the figure.