1. Design requirements and goals
The MQ-5 sensor is used to realize the detection of natural gas, the data is collected, after A/D conversion, and then processed by the single-chip microcomputer, and the processed data is analyzed, whether it is greater than or equal to a certain preset value (that is, alarm Limit), if it is greater than, it will automatically start the alarm circuit to sound the alarm and the fan, otherwise it is normal.
Specific realization functions:
1. MQ-5 detects gas concentration in real time. The concentration is divided into 3 levels of low, medium and high, and indicated by green light, yellow light and red light respectively. When the concentration reaches the corresponding level, the corresponding light is on and the indicator light indicates safety status.
2. When the concentration reaches a high level, the buzzer will alarm and the fan will start to evacuate the gas.
3. When the concentration reaches the mid-range, the relay is turned off.
2. Design ideas and plans
This design consists of STC89C52 single-chip microcomputer + MQ-5 sensor module circuit + 3 LED indicator circuits + buzzer alarm circuit + PCF8591AD module + fan control circuit + relay control circuit + power supply circuit. The design block diagram is shown in the figure.
3. Hardware circuit diagram
All materials include programs (notes), AD schematic diagrams, protues simulation, reference papers, program explanations, simulation explanations, simulation videos, schematic explanations, introductions to the use of materials, etc., the most comprehensive network! ! ( Https://www.cirmall.com/circuit/18387 )
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