Introduction:
A motion detector is a device that contains a motion sensor that detects moving objects and transforms the detection of motion into an electric signal. A sensor is basically a device that receives a stimulus and responds with an electrical signal. The process of receiving a stimuli and giving a response is referred to as sensing. Sensing activities may include collection of values for temperature ,vibration,pulse,humidity and other health-related information and data
It is often integrated as a component of a system that automatically performs a task or alerts a user of motion in an area. Motion detectors form a vital component of security, automated lighting control, home control, energy efficiency, and other useful systems
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Figure 3 AMN31111 sensor
Figure 4 Electrical characteristic from AMN31111 datasheet
Figure 5. AMN31111 sensor digital and analog block diagram
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It detects variations in infrared rays. However, it may not detect in the following case: lack of movement, no temperature change in the heat source
Signal can converted to digital by external A/D converter. It also can be connected directly to microcomputer. Signal may not be need to convert to digital if digital version of the sensor is chosen.
It's calibrated to detect differences in the temperature between the background and the object, movement speed and the object(human body).
Some noise is detected in the sensor, typical noise value being 155 m Vp-p to maximum of 300 m Vp-p. A noise filter is recomemded recommended for applications requiring enhanced detection, reliability and noise withstanding capability.
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The sensors circuit is entirely enclosed in a TO-5 metal package which is standardized metal semiconductor package. The front surface of the lens and case are made of polycarbonate and the lens is made of soft materials, polyethylene. The materials are resistant to water, alcohol, oil, salt and weak acids which allows it to be use outdoors but not recommended if not waterproofed.
Group members:
Mohammad Shahidul Islam, Riku Sorsa
PRESENTATION
References:
http://www.ehow.com/how-does_4596955_motion-sensor-work.html
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http://images.machinedesign.com/images/archive/72829sensorsens_00000051108.jpg
http://www3.panasonic.biz/ac/e/control/sensor/thumbnail/amn31111.gif
http://www.panasonic-electric-works.com/cps/rde/xbcr/eu/ds_61804_en_pir_motion_sensor.pdf
