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====== Human Detection Sensor System ====== The human detection sensor system consists of a variety of sensors oriented in such a way that they can be used to detect and track the presence of humans. In our current design, there are three types of sensors: PIR Motion Detectors, Infrared Thermometer Arrays, and an ultrasonic distance measuring device. ===== PIR Motion Detectors ===== {{ :gallery:pirsensor.gif|Courtesy of Glolab}} These sensors are comprised of a [[http://www.glolab.com/pirparts/pirparts.html|Pyroelectric Infrared Sensor]] along with a custom designed amplifier circuit. A datasheet for the Pyroelectric Sensor can be found below. Due to the complexity of the amplifier circuit, the team decided to print PCB's for these boards in an effort to save time and effort. The amplifier circuit can be seen in the gallery below. {{:pir-diagram.jpg?150 |Courtesy of Glolab}}The Pyro-Sensors is used to detect the movement of humans (or any heater body) in a defined field of view. These sensors work by using two active elements to detect relative direction of motion of a heated body. When an object moves in the sensors field of view, a voltage waveform is produced. An example waveform can be seen to the left. Each sensor has about 90 degrees viewing angle but, with the help of a Fresnel lens and blinders, the final setup will consist of four sensors each with 45 degree viewing angle. The output from the Pyro-Sensors cannot be read directly into the microcontroller, so the team has constructed an amplification circuit capable of amplifying the signal with a variable-gain of over 10,000 (80dB). The amplifier is a simple two-stage Op-Amp circuit using the LM324 series Op-Amps. The amplifier circuit can be seen in the gallery below. ^ [[photos|Photo Galleries]] ^ | [[Gallery-PIR|{{:gallery:dscn3002.jpg?150|}}]] | | [[Gallery-PIR|PIR Amplifier]] | ==== Datasheets ==== * {{:datasheets:pirmanual.pdf|Pyroelectric Infrared Sensor}} * {{:datasheets:lp324n.pdf|LP324N Op-Amp}} ===== Infrared Thermopile Array ===== ===== Ultrasonic Distance Measure =====

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