AN1828/0304

1/17

Rev. 1.0

AN1828

APPLICATION NOTE

PIR (PASSIVE INFRARED) DETECTOR USING

ST7FLITE05/09/SUPERLITE

INTRODUCTION

The document explains how to design a low cost PIR detector (human motion detector) using

the ST7FLITE05(09) microcontroller family. The technique used is software Sigma-Delta A/D

Conversion, suitable for detecting low-frequency sensor signals. Refer to AN1827 for a de-

tailed explanation of the Sigma-Delta technique. The same concept can also be used for other

sensor applications such as:

– Security Systems.

– Automatic lighting Systems

– Automatic Door Openers

1ddd