Zero false alarm rate, real-time response Accurate data Minimum distinguishable particle diameter: 0.3 micrometer High anti-interference performance due to six-sided shielding patent structure Optional air inlet and outlet direction for different design compatibility PIN1: VCC power supply 5V PIN2: GND power ground PIN3: NC (No Connection) 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 (No Connection) PIN8: PWM pulse width signal output pin (3.3V level) Circuit design: 1) D9 requires 5V power supply as the fan needs 5V drive. Data communication and control pins require 3.3V high level. The main board MCU should be powered at 3.3V. If using a 5V MCU, 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, and PIN5; other pins not required. 3) For PWM output, only connect PIN1, PIN2, and PIN8; other pins not required. Color: Silver Material: Metal Package Contents: 1 x Sensor Module (Other items not included) Note: Light reflection and display differences may cause slight color variation between image and actual item. Measurement error allowed within +/- 1-3 cm.