Zero false alarm rate, real-time response, correct data. Minimum distinguishable particle diameter: 0.3 micrometer. High anti-interference performance due to patented six-sided shielding structure. Optional air inlet and outlet direction to accommodate different designs. PIN1: VCC power supply 5V PIN2: GND power ground PIN3: NC PIN4: RXD: Serial port receiving pin (3.3V level) PIN5: TXD: Serial port sending pin (3.3V level) PIN6: RESET: Suspended during use; lowering may cause module malfunction PIN7: NC PIN8: PWM: PWM pulse width signal output pin (3.3V level) Circuit design considerations: 1) D9 requires a 5V power supply as the fan needs 5V drive. However, data communication and control pins require 3.3V high level. Therefore, the main board MCU connected for communication should be powered at 3.3V. If the MCU is powered at 5V, a level conversion chip or circuit must be added on communication lines (RXD, TXD) and control lines (SET, RESET). 2) For serial output, only connect PIN1, PIN2, PIN5; other pins not required. 3) For PWM output, only connect PIN1, PIN2, PIN8; other pins not required. Color: Silver Material: Metal Package Contents: 1 x Sensor Module Only the above package content included; other products not included. Note: Light reflection and differences in display screens may cause slight color variations between the image and the actual item. Measurement error allowance: +/- 1-3 cm.