Design of gas alarm based on microcontroller

Based on the above requirements of this design, according to the functional requirements, a download circuit, display circuit, LED control circuit, timing circuit, alarm circuit must be designed. Each circuit of the main control circuit has its own function. By resetting the button "KEY1", the circuit enters the ready state. Then the sensor starts to warm up for about 20 seconds. The preset initial value is 60, and then detects the surrounding concentration in real time. If the detected concentration is normal, the alarm circuit will not work and enter the sleep state, and the screen will display normal. If the smoke concentration in the home exceeds the preset value, the alarm circuit will alarm, and the LED will continue to flash, and the alarm will be displayed on the screen! . Residents are reminded to be careful. The concentration value can also be adjusted manually, plus or minus. When the maximum threshold is set, the alarm circuit can also alarm and needs to be closed manually.