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Receiving and decoding LaCrosse sensors - RS232


Most of LaCrosse sensors use 433MHz frequency to send the meteorologic data. Only part of sensors (using a On/Off modulation) are decoded by this receiver. Other sensors, like IT+ (using a different modulation) are not decoded.

Here is a list of sensors I have already interfaced. Other may be decoded but they are not verified.

Data encoding

There are two main kind of data encoding: TX series and WS series. This receiver decodes de frames of these two kinds of data encoding.

Modulation and timings are described in these pages:

Data frame are send periodically between one to five minutes. The content of the frames is specific to each sensor and described in these pages.

The receiver

The RF signals are received by a low-cost module AUREL 4M50RR30SF. The data are decoded by a 8 pins PIC 12F675 which checks and recodes received frames to a RS232 DB9 port via a MAX232(or LT1081). RS232 line parameters are 4800 bauds 8 bits, no-parity, 1 stop bit. The protocole used to send RS232 frames is described here.

Schematics, components, part list and printed board are available in pdf format

Source code written in PIC assembler and Hex code are available and generated with MPLAB IDE.

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