Posts tagged IR Sensor
Infrared Thermometry Theory and Applications with Arduino and Python

In this tutorial, I will explore black body radiation, infrared detectors, and the relationship between temperature and emissivity - all with the intention of exploring how infrared (IR) detectors measure temperature from a distance. Arduino will be used, along with an MLX90614 IR thermometer, and a thermocouple for true-temperature approximation of each object. Planck’s discovery of energy quanta and their relationship to thermodynamics is the basis for radiation detectors and infrared temperature sensors. We will use Planck’s law to derive a usable equation that can relate the radiation measured by an infrared sensor to the temperature of a radiative object.

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Arduino Interrupts with PIR Motion Sensor

The basics of Arduino’s hardware interrupt is explored through the use of a passive infrared (PIR) sensor. The passive infrared sensors used here operate at voltages from 2.7V - 5V and use very little energy when operating in the non-tripped state. The PIR sensor is ultimately tripped by an infrared source, typically human body heat (or another animal with similar radiative emission). When the PIR sensor is tripped it sends a HIGH signal to its OUT pin, which will be read by the Arduino’s interrupt pin (pin 2 or 3 on the Uno board). This process seems trivial, but when done correctly can save massive amounts of energy when dealing with battery-powered systems, as in home automation.

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