Gas sensors are devices that convert information such as gas composition and concentration into information that can be used by personnel, instruments, computers, etc. Gas sensors include: Semiconductor gas sensors, electrochemical gas sensors, catalytic combustion gas sensors, thermal conductivity gas sensors, infrared gas sensors, etc.

Gas sensors are commonly used detection instruments and have certain applications in many fields such as coal mining, petroleum, chemical industry, electronics, and metallurgy. Therefore, there are certain selection skills when choosing a gas sensor, so that the most suitable gas sensor can be selected. Today, the editor of Luftmy will introduce the selection techniques of gas sensors in detail, hoping to help everyone.

I. Selection of Sensitivity

Generally, within the linear range of the sensor, it is desirable for the sensor's sensitivity to be as high as possible. This is because only when the sensitivity is high will the output signal value corresponding to the change in the measured quantity be relatively large, which is beneficial for signal processing. However, it should be noted that if the sensitivity is high, external noise unrelated to the measured quantity is also easily mixed in and will be amplified by the amplification system, affecting measurement accuracy. Therefore, the sensor itself is required to have a high signal-to-noise ratio to minimize interference signals introduced from the outside. Sensor sensitivity is directional. When the measured quantity is a single vector and has high requirements for directionality, a sensor with low sensitivity in other directions should be selected; if the measured quantity is a multi-dimensional vector, the cross-sensitivity of the sensor should be as small as possible.

II. Based on Measurement Object and Environment

Determine the type of sensor based on the measurement object and environment. To carry out a specific measurement task, the first consideration is what principle the sensor should use, which requires analyzing many factors. Even for measuring the same physical quantity, there are sensors with various principles available. Which principle is more suitable needs to be considered based on the characteristics of the measured quantity and the conditions of sensor use: the size of the range; the space requirements of the measured position for the sensor volume; whether the measurement method is contact or non-contact; the signal extraction method (wired or non-contact measurement); the source of the sensor (domestic or imported, affordability of the price, or self-developed). After considering the above issues, the type of sensor can be determined, and then the specific performance indicators of the sensor can be considered.

III. Linear Range

The linear range of a sensor refers to the range where the output is proportional to the input. Theoretically, within this range, the sensitivity remains constant. The wider the linear range of the sensor, the larger its measuring range, and a certain measurement accuracy can be guaranteed. When selecting a sensor, after the type of sensor is determined, the first thing is to see if its range meets the requirements. In practice, however, no sensor can guarantee absolute linearity, and its linearity is also relative. When the required measurement accuracy is relatively low, within a certain range, a sensor with a small non-linear error can be approximately regarded as linear, which provides great convenience for measurement.

IV. Response Characteristics / Response Time

The frequency response characteristics of the sensor determine the frequency range of the measured quantity. Measurement conditions must be maintained without distortion within the allowed frequency range. In fact, there is always a certain delay in the response of the sensor, and it is hoped that the delay time is as short as possible. If the frequency response of the sensor is high, the detectable signal frequency range is wide. Due to the influence of structural characteristics, mechanical systems have large inertia, so sensors with low frequency can only measure lower frequencies. In dynamic measurement, the response characteristics should be based on the characteristics of the signal (steady-state, transient, random, etc.) to avoid excessive errors.

Application benefits in vacuum cleaners and sweeping robot products:

①. The dust cleaning effect of the equipment and the cleanliness of floors, carpets, bed sheets, etc., are intuitively presented to the user through sensor output data and LED color displays;

②. The equipment intelligently controls the motor speed based on sensor data to achieve silence, energy saving, power saving, and extension of motor life.