The manufacture of smoke alarm needs liquid crystal display, temperature display and single chip microcomputer control.

The smoke alarm can be made by MSP430F4 13 single chip microcomputer. This single-chip microcomputer comes with LCD driver module, which has low power consumption and can drive up to 96 segments. Some ports have the functions of interruption and voltage comparison capture, which is especially suitable for making ultra-low power testing instruments. Someone once made an electronic watch with this series of single-chip computers. Using coins and copper sheets as electrodes and inserting them into fruits, it can work, while using ordinary No.7 battery for power supply, it can work continuously for more than 5 years.

The temperature display part can be 18B20. The internal temperature value is corrected by laser before leaving the factory, and the measurement result can be accurate to 0.5 degrees.