Add support for Aldi Sempre 4-AH0423-4 temperature/rain sensor

[sorny]

See the discussion in #1837

[Gollam]

The changes you made look good for the Sempre type sensor, but will it continue to work with the original Auriol ones? As I understood, the Sempre sends more fields, so Auriol decoding will fail, isn't it?

[sorny]

I checked with the available binary samples from #1837 and they all work was expected.

Auriol samples:
rtl_433 -y {52}1a8088f000145

Model : Auriol-4LD5661 ID : 1a
Channel : 1 Battery : 1 Temperature: 13.6 C Rain : 325.0 mm Rain tips : 325

rtl_433 -y {52}c6806bf00000f

Model : Auriol-4LD5661 ID : c6
Channel : 1 Battery : 1 Temperature: 10.7 C Rain : 15.0 mm Rain tips : 15

Sempre sample:
rtl_433 -y {52}9fb0bcf0000ef

Model : Auriol-4LD5661 ID : 9f
Channel : 4 Battery : 1 Temperature: 18.8 C Rain : 239.0 mm Rain tips : 239

Low battery sample:
rtl_433 -y {52}1a00faf000001

Model : Auriol-4LD5661 ID : 1a
Channel : 1 Battery : 0 Temperature: 25.0 C Rain : 1.0 mm Rain tips : 1

[zuckschwerdt]

Does the unit have a channel selector? What are the markings on that?

[zuckschwerdt]

If there is no channel we should just add the docs and change the check, e.g.

// Flags are 0 for Auriol and 2 for Sempre
if (b[3] != 0xf0 || (b[1] & 0x70) != 0) || (b[1] & 0x70) != 0x2) {

(if 0x2 is the fixed value)

[sorny]

Reworked the check to evaluate the unknown, seemingly always 0 bit after the battery flag

[zuckschwerdt]

This will ignore the two bits. But don't we want to check that it's 0 or 3? I.e. 1 or 2 are invalid.

[sorny]

Depends, no idea if there are other brands of this rain meter out there that would use either ch1 or ch2 :/

[zuckschwerdt]

You are getting a "channel" value of 3, right? With the Nexus logic of C+1 that would be CH4? So 0…2 as channel (as Nexus has) and then 3 for rain would be a good guess here?

[sorny]

Yeps, I am getting channel 4 for my sempre rain meter, based on the nexus channel logic. The samples for Auriol result in channel 1 which could make sense that different brands use different channels for the rain meter.