Fish tank oxygenation timer circuit

Nowadays, many people like to keep fish in their homes. I think the following things may be useful. I wanted to make this thing when I saw something similar when I was playing at a friend's house. My friend's fish tank doesn't have many fish, so he doesn't need to turn on the oxygenator continuously, and he is too lazy to turn the oxygenator on and off every day, so he bought something similar to this. He wanted another one, so I made one for him. Circuit principle: The circuit is simple and mainly controlled by the microcontroller AT89C2051. The 220-volt AC power supply in the circuit is stepped down by the transformer, full-bridge rectified, filtered by C5 and C6, stabilized by the three-terminal voltage regulator 7805 and filtered by C7 and C8, to provide a stable 5-volt power supply to the microcontroller. LED2 is used to indicate circuit power status. LED1 is used to indicate whether the oxygenator is working. When the oxygenator is working, LED1 lights up. S1 is used for circuit reset. When the microcontroller crashes due to interference, you can press S1 to reset. S2 is used to set the time to turn on the oxygenator, the settable time is 1"29 minutes, S3 is used to set the interval time when the oxygenator does not work, the settable time is 1"5 hours, S4 is used to display all set time.