Introduction of smoke detector

Smoke alarm is an instrument that can detect the concentration of smoke in the environment and has alarm function. The most basic components of the instrument should include: smoke signal acquisition circuit, analog-to-digital conversion circuit and single chip microcomputer control circuit. The smoke signal acquisition circuit generally consists of a smoke sensor and an analog amplifier circuit; Convert smoke signals into analog electrical signals. The analog-to-digital conversion circuit converts the analog signal sent by the smoke detection circuit into a digital signal that can be recognized by the single chip microcomputer and then sends it to the single chip microcomputer. Single chip microcomputer filters the digital signal and analyzes the processed data. Whether it is greater than or equal to a preset value (that is, the alarm limit), if it is greater than, the alarm circuit is started to give an alarm sound, otherwise it is in a normal state. In order to facilitate detection and monitoring, so that instrument testers and users can intuitively observe the concentration value of combustible smoke in the environment, the concentration value can be sent to the display screen. It is easy to adjust the alarm limit, and buttons can be added. In order to make the alarm device more perfect, we can add light flashing alarm on the basis of sound alarm. The changing light signal can attract users' attention and make up for the limitations of sound alarm in noisy environment.

The smoke sensor is a gas sensor, which is a gas/electricity converter. It converts the content (concentration) of combustible gas in the air into voltage or current signal, and the analog signal is converted into digital signal through A/D conversion circuit, and then sent to single chip microcomputer, which then completes data processing, concentration processing and alarm control. As the signal acquisition part of smoke detection alarm, sensor is one of the core components of the instrument. It can be seen that the choice of sensor is very important. The outstanding advantages of semiconductor smoke sensor are high sensitivity, fast response, good anti-interference, convenient use, low price, no probe delay and low maintenance cost.