Wie weiter oben schon gesagt sind die Pyro Senoren nicht so gut für die Temperaturmessung geeignet, sieh noch mal im PerkinElmer Datenblatt nach bei den Beschreibungen mit Bildern über das Zeitverhalten.
Manfred

Pyroelectric materials produce a charge transfer when they undergo a change in thermal energy. This effect is applied for detectors that show an output signal similar to alternating current with a change in the infrared radiation. Such pyroelectric detectors are used in movement detectors, passive infrared alarms, and automatic light switches. Detectors based on the same principle are used for gas monitoring based on the spectral absorption method.

Thermopile detectors directly sense thermal radiation, providing the perfect device for remotely measuring temperatures without the need for any mechanical chopper. PerkinElmer’s proprietary and innovative Si-based micromachining technology guarantees a new generation of components: extreme long-term stability, very low temperature coefficient in sensitivity, and excellent repeatability of electro-optical parameters.
Thermopile sensors allow remote temperature sensing at a low system cost. The sensor does not require cooling, and can reach an accuracy of ±1°C, dependent on the measurement range. For narrow temperature ranges, as in body temperature measurement, a precision of 0.1°C is possible.