Senba D204S 2-Element Pyroelectric Infrared Analog PIR Sensor

The dual-element design enables differential sensing, where the two pyroelectric crystals are connected in opposite polarity. This configuration cancels out common-mode signals caused by ambient temperature changes or slow environmental drift, making the sensor significantly more sensitive to the fast-changing infrared pattern created by a moving human body, thereby reducing false alarms.

The sensor's high-level analog output (≥3500mV Vp-p) can be directly connected to an Arduino's analog input pin (A0-A5). For reliable detection, you should first buffer and possibly amplify the signal using an op-amp configured as a non-inverting amplifier if your detection distance is very long. In code, read the analog pin and set a threshold value to trigger an event when the signal exceeds the baseline noise level.

The absolute maximum supply voltage specified is 15V DC. For optimal performance and longevity, it is recommended to operate the sensor within the middle of its range, such as 5V or 12V, which are common standards in security system panels. Ensure your power supply is clean and regulated, as voltage spikes or ripple can affect the sensor's offset voltage and noise performance.

While the sensor itself operates from -30°C to +75°C, the TO-5 package is not inherently waterproof (IP-rated). For outdoor use, it must be installed inside a sealed, weatherproof enclosure with a clean IR-transmissive window (like polyethylene or silicon) that does not block the 5–14μm spectral range. Direct exposure to rain, condensation, or UV sunlight will damage the sensor and its window.