MIKROE PIR Click is a pyroelectric sensor which generates a voltage when exposed to infrared radiation emitted by live bodies. It is equipped with the PL-N823-01, an infrared sensor from KEMET that uses the pyrolectric effect of ceramic by absorbing infrared rays emitted from the human body, while the the white plastic Fresnel lens covering the sensor filters visible light. This detects the natural infrared signature produced by humans. However, it can also detect infrared rays without using lenses.

PIR Click is supported by a mikroSDK compliant library, which includes functions that simplify software development.

The PIR sensor is a kind of thermal sensor which is able to detect the movement of a heat source. As the most general heat source in indoor environments, humans with motion can be detected by PIR sensors. However, this sensor cannot detect static human subjects. We call this sensing mode “passive sensing”, since the sensor itself is passively triggered by moving subjects. It is important to state that the sensor can be used for developing various applications, the typical ones including human presence detection sensing for energy saving functions in: contactless switching, building or office automation equipment, home applicances, lighting, display products, air-conditioners, TV, PC monitors, rice cookers and many more.

The main component of the PIR Click is the PL-N823-01 –a PL Pyroelectric Infrared Sensors from KEMET. Due to the absence of a lens, KEMET’s Pyro Sensor is low profile, as it does not protrude, which makes it ideal for gathering visual requirements. With KEMET’s proprietary piezoelectric ceramic material and element structure of the Pyroelectric Infrared Sensor, you can also detect humans through glass or resin. This allows more freedom in the design of the outer appearance of the end product.

Such a sensor system aims to provide the reliable human detection and human scenario perception. In order to achieve this goal, a conditioning sensing circuit with a low-noise signal amplifier with adjusted amplification gain is developed. Besides, the gain amplification, the onboard circuit serves also as a proprietary 1Hz signal filter, which ensures rejection of all unwanted components of the signal. That way, a reliable movement detection system is achieved. The output signal is routed to the AN pin of the mikroBUS™, as well as to the MCP3221 – a 12-Bit A/D Converter with I2C Interface, from microchip. That way, the user can choose whether to read the output signal via the I2C interface, or directly, by reading the voltage on the analog pin of the used MCU.

Some of the numerous benefits of using this particular Click, equiped with the PL-N823-01 infrared sensor, are a wide view angle up to 60 degrees ether way, detection possible through glass or resin, low power consumption, excellent radio wave performance in high-frequency band, a compact and low profile (5.0x4.8x1.7mm) and all of this is possible without a lens because it is not required. The low power consumption that we are speaking of is down in the μA range. When it comes to the performance characteristics, the operating temperature should be between -40C to +70C and the storage temperature should be between -40C to +85C.

The PIR Click board™ offers a selection between 3.3V and 5V operation, with the onboard SMD jumper, labeled as PWR SEL. This allows both 3.3V and 5V MCUs to be interfaced with this Click board™.

• Interface: GPIO, I²C
• Compatibility: mikroBUS™
• Dimensions: 42.9 x 25.4mm
• Input Voltage: 3.3V or 5V

• Schematic
• PL-N823-01 Datasheet
• mikroSDK
• GitHub