The Important Role of Crystal Oscillator in Infrared Temperature Measuring Gun

Any object above absolute zero (- 273 ℃) will emit infrared rays, the infrared temperature measuring gun receives the infrared through the sensor and obtains the induction temperature data. This is the working principle of the infrared temperature measuring gun.

The infrared temperature measuring gun is designed to measure the forehead temperature of human body, which realizes the purpose of non-contact temperature measurement and is easy to operate. One second can accurately measure temperature, effectively reduce the risk of cross infection between people.

The infrared temperature measuring gun is mainly composed of the following parts:

Crystal oscillator

The function of crystal oscillator is to provide reference clock signal for MCU, so as to ensure the smooth implementation and completion of MCU instructions.

MCU microprocessor

Receive and process the data of infrared temperature sensor.

Infrared temperature sensor

It is used to collect human body temperature. The infrared temperature measuring gun is generally 1 ~ 3cm away from the forehead. The collected data is amplified by the signal amplification circuit.

Key module

It is used to realize the functions of on-off, mode switching and system reset.

LCD display

Used for temperature display.

Buzzer

Alarm module. If the safe temperature range is 35 ℃ ~ 37.3 ℃, if it exceeds the upper or lower limit of this temperature range, the buzzer will start the alarm function.

Requirements of infrared temperature measuring gun for crystal oscillator:

Frequency stability and accuracy

If the crystal oscillator is unstable in the actual work, such as too large frequency offset or no vibration, it will directly cause the MCU to lose the command function. The bad phenomena are not starting, the LCD display can not be lit, or the temperature measurement is slow.

Chip crystal oscillator is often used in the design of common infrared temperature measuring gun, and the package size and frequency point are as follows:

SMD3225 12MHZ ±10ppm

SMD3215 32.768kHz ±10ppm

The function of crystal oscillator 12Mhz is to provide clock signal source for MCU and complete instruction cycle. The main function of 32.768KHz crystal oscillator is to provide RTC (real-time clock) function.

Low power consumption

Infrared temperature measuring gun is a portable electronic instrument, which needs battery power supply, so there is a low power consumption demand for crystal oscillator. The crystal oscillator selection is mostly chip type, small volume and low power consumption.

In short, the more stable and accurate the crystal oscillator is, the faster and more accurate the infrared temperature measurement gun is.