PIR Sensor is the most commonly used contact less Infrared based sensor used in the market today. the major advantage is that these are available as PCB modules as shown above and are less costly. With the current COVID scenario, there has been lot of demand for the non-touch based systems like auto dispensers, auto lighting based on human movement. In all these applications, PIR sensor plays a crucial role. PIR sensors have pyroelectric sensor which can be used to detect the levels of Infrared radiation. BISS0001 is used for processing the output of the pyroelectric sensor and a digital output is provided as output to the end user which is an indicator of the motion. This sensor can detect up to 6m distance. The output digital signal has a voltage of 3V and can easily interfaced to a modern day microcontrollers without any level translator. There are many vendors who make this sensor PCB and designer has to check if there is any on-board regulator or 5V is directly applied to BIS chip. As the BIS chip decides the Digital output level, it is important that designer has to know what voltage is applied to BIS. BIS can work in the range from 3 to 5V.
The below image indicates the features and connectivity options around the sensor PCB.
Below is a sample circuit which powers a 5V load using relay based on sensor detection. This is an imaginary example and can be optimized. Relay need to be required unless an isolation is mandatory in this scenario.
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