Finally I have more time to play with this setup.
I am following this guide:
http://rayshobby.net/reverse-engineer-w ... rs-part-1/
I did my best, but am unable to receive any data with the program for RPi.
The receiver/transmitter is working, because I am able to receive/send signal with 433Utils (RFSniffer) from my ON/OFF RF switch.
Let's move on my Weather Sensor:
I build a sniffer from a cheap USB sound card + RXB6 receiver, here is the result:
https://f001.backblazeb2.com/file/mihal ... sensor.wav
If am not wrong, I red these values from Audacity:
sync_length (selection start)20223-19823(selection end) = 400 / 44.1 = 9.07ms
0 (or 1?) 20337-20255 = 82 / 44.1 = 1.85ms
1 (or 0?) 20528-20360 = 168 / 44.1 = 3.80ms
sep length 20359-20335 = 24 / 44.1 = 0.54ms
First, I tried the default values in the program, where are nearly same values: not working.
Then, I modified the values to:
#define RING_BUFFER_SIZE 256
#define SYNC_LENGTH 9000
#define SEP_LENGTH 500
#define BIT0_LENGTH 3800
#define BIT1_LENGTH 1850
Then I fired up my RTL SDR device and rtl_433 utils, with this, I am able to receive and decode signal. The sensor is recognized as a prologue sensor, here is the source of this module:
https://github.com/merbanan/rtl_433/blo ... prologue.c
From the description in the code:
the sensor sends 36 bits 7 times, before the first packet there is a sync pulse
the packets are ppm modulated (distance coding) with a pulse of ~500 us
followed by a short gap of ~2000 us for a 0 bit or a long ~4000 us gap for a
1 bit, the sync gap is ~9000 us.
…so I am working with correct values.
But then why I am unable to receive anything without RTL SDR?