Improve Altronics X7064 and add support for EMAX Weather Station

[ProfBoc75]

Hi,

I bought this weather station, Optex SM40 990040, but I have a wrong decode situation.
https://www.bricodepot.fr/catalogue/station-meteo-couleur-professionnelle-connectee/prod84533/

This weather station is composed of an External Temp Humidity sensor, well decode as Altronics X7064.

• Another multi-sensor Rain Gauge/Wind Speed/UV/LUX/TEMP/HUMIDITY but this one is not well decode, report only the temp and badly the humidity %.

First the Optex weather station is a rebrand of Fuzhou Emax Electronic weather station W6, and I found that other brands like Altronics x7063, Infactory (FWS-1200) , Newentor Q9 are also rebrand this Emax weather station, the reference is known as EM3390W6.

After a deep dive I found the reason of the bad decode and share here my findings ;

The Rain Wind milti-sensor provides more data than the Temp/Hum sensor and not in the same order.

Here the differences :
Temp/Hum Sensor :
AA KC II IB AT TA AT HH AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA SS

default empty = 0xAA

• K: (4 bit) Kind of device, = A if Temp/Hum Sensor or = 0 if Weather Rain/Wind station
• C: (4 bit) channel ( = 4 for Weather Rain/wind station)
• I: (12 bit) ID
• B: (4 bit) BP01: battery low, pairing button, 0, 1
• T: (12 bit) temperature in F, offset 900, scale 10
• H: (8 bit) humidity %
• A: (4 bit) fixed values of 0xA
• S: (8 bit) checksum

Raw data:

FF FF AA AA AA AA AA CA CA 54
AA A1 6E 95 A6 BA A5 3B AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA D4
AA 00 0

Format string:

12h CH:4h ID:12h FLAGS:4b TEMP:4x4h4h4x4x4h HUM:8d 184h CHKSUM:8h 8x

Decoded example:

aaa CH:1 ID:6e9 FLAGS:0101 TEMP:6b5 HUM:059 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa CHKSUM:d4 000

Emax EM3390W6 Rain / Wind speed / Wind Direction / Temp / Hum / UV / Lux

Weather Rain/Wind station : humidity not at same byte position !
AA 04 II IB 0T TT HH 0W WW 0D DD RR RR 0U LL LL 04 05 06 07 08 09 10 11 12 13 14 15 16 17 xx SS yy

default empty/null = 0x01 => value = 0

• K: (4 bit) Kind of device, = A if Temp/Hum Sensor or = 0 if Weather Rain/Wind station
• C: (4 bit) channel ( = 4 for Weather Rain/wind station)
• I: (12 bit) ID
• B: (4 bit) BP01: battery low, pairing button, 0, 1
• T: (12 bit) temperature in F, offset 900, scale 10
• H: (8 bit) humidity %
• R: (16) Rain
• W: (12) Wind speed
• D: (9 bit) Wind Direction
• U: (4 bit) UV index
• L: (1 + 15 bit) Lux value, if first bit = 1 , then x 10 the rest.
• A: (4 bit) fixed values of 0xA
• 0: (4 bit) fixed values of 0x0
• xx: incremental value each tx
• yy: incremental value each tx yy = xx + 1
• S: (8 bit) checksum

Raw Data: the beginning of the Preamble is not exactly the same,

ff ff 80 00 aa aa aa aa aa ca ca 54
aa 04 59 41 06 1f 42 01 01 01 81 01 16 01 01 01 04 05 06 07 08 09 10 11 12 13 14 15 16 17 9d ad 9e
0000

Format string:

8h K:4h CH:4h ID:12h Flags:4b 4h Temp:12h Hum:8h 4h Wind:12h 4h Direction: 12h Rain: 16h 4h UV:4h Lux:16h  112h xx:8d CHKSUM:8h

Decoded example:

aa KD:0 CH:4 ID:594 FLAGS:0001 0 TEMP:61f (66.7F) HUM:42 (66%) Wind: 101 ( = 000 * 0.2 = 0 kmh) 0 Direction: 181 ( = 080 = 128°) Rain: 0116 ( 0015 * 0.2  = 4.2 mm) 0 UV: 1 (0 UV) Lux: 0101 (0 Lux) 04 05 ...16 17 xx:9d CHKSUM:ad yy:9e

So I rewrite the decoder in order to get these information, notice that the gap needed to be changed from 900 to 1200.
Because I get the both sensors, Temp/Hum + Rain/Wind, I was able to test the decoding correctly.
emax.c replace altronics_x7064.c for a generic decoding of this protocol.

All here : https://github.com/ProfBoc75/rtl_433_tests/tree/patch-2/tests/fuzhou_emax

Thx.

[ProfBoc75]

I just open the Pull request #2300

Thx.

[zuckschwerdt]

This is great! Thanks!

[ProfBoc75]

New support and improvement done today.

Thanks a lot to rtl_433 team !