Pyroelectricity

The earliest observation of the pyroelectric effect occurred in 314 B.C., when the ancient philosopher and scientist Theophrastus noticed that tourmaline minerals create electrical attraction when they are heated.

In piezo crystals, for instance, physical force such as bending a mineral will generate electricity. Similarly, pyroelectricity results from the interaction of the thermal and electrical properties of a crystal.

The amount of electricity produced by the pyroelectric effect is typically not enough to power other devices. This means that pyroelectricity is not a practical power generation method.

Each detector contains a wide-angle lens and a pyroelectric crystal.

When a person walks past the sensor, their body heat causes the crystal to generate pyroelectricity and the alarm is activated.

Pyroelectric sensors can be used to detect other sources of heat, such as fire.

Unlike traditional smoke detectors, a sensor that uses pyroelectricity is able to detect an actual flame even if smoke is not present.