The DSM501A PM2.5 Dust Sensor Module detects fine airborne particles as small as 1 micron, including smoke, dust, pollen, and mites. It uses a built-in heater for silent thermal airflow and provides a PWM output for easy microcontroller interfacing. Operating at 5V DC, it is ideal for air quality monitors, air purifiers, HVAC systems, Arduino projects, and DIY environmental monitoring.

The HC-SR501 PIR Motion Sensor Module detects human and animal movement using infrared sensing, with an adjustable 3–7m detection range and 5–200s delay. Operating at 4.5V–20V, it provides a digital HIGH/LOW output and low power consumption. Ideal for security systems, automatic lighting, robotics, Arduino, ESP32, and Raspberry Pi projects.