Add support for ELRO home control remote

[jenskdsgn]

ELRO AB440R is a simple power socket on and off switch

[zuckschwerdt]

This is very likely just the tenary signal of a EV1527 or similar. Best to use a flex decoder for such remotes, see https://github.com/merbanan/rtl_433/tree/master/conf

[jenskdsgn]

@zuckschwerdt can you point me to some documentation of flex decoder so I can give it a try?

[zuckschwerdt]

We only have the examples in the conf files and the short help from rtl_433 -X for now.

[jenskdsgn]

I don't see how I can only take even-bits into consideration and use the odd-bits which are always 1 as some kind of sanity check.

[zuckschwerdt]

They are only always on by chance, the third ternary symbol just isn't used here.

For the

BBBB:  1000 = button A
       0100 = button B
       0010 = button C
       0001 = button D
SS:    10 = ON
       01 = OFF

You can view the full pattern as

1B1B1B1B:  11101010 = 0xea = 234 = button A
           10111010 = 0xba = 186 = button B
           10101110 = 0xae = 174 = button C
           10101011 = 0xab = 171 = button D
1S1S:      1110 = 0xe = 14 = ON
           1011 = 0xb = 11 = OFF

And e.g. then write getters:

get=@10:{8}:button:[234:A 186:B 174:C 171:D],
get=@20:{4}:toggle:[11:OFF 14:ON],

Since channel is fixed you best filter that with a match=

[jenskdsgn]

They are only always on by chance, the third ternary symbol just isn't used here.

For the

BBBB:  1000 = button A
       0100 = button B
       0010 = button C
       0001 = button D
SS:    10 = ON
       01 = OFF

You can view the full pattern as

1B1B1B1B:  11101010 = 0xea = 234 = button A
           10111010 = 0xba = 186 = button B
           10101110 = 0xae = 174 = button C
           10101011 = 0xab = 171 = button D
1S1S:      1110 = 0xe = 14 = ON
           1011 = 0xb = 11 = OFF

And e.g. then write getters:

get=@10:{8}:button:[234:A 186:B 174:C 171:D],
get=@20:{4}:toggle:[11:OFF 14:ON],

Since channel is fixed you best filter that with a match=

This is clear but the bits that are reversed for the channel information is quite tricky and I think can only be programmatically be solved unless we want to map each channel to the pattern which would be 32 pattern.
Let me know how to proceed here.

[zuckschwerdt]

Ideally we need more decode helpers like the decode_uart in the flex spec. A decode_ternary or decode_x1527 would be nice (and could also sanity check).

[zuckschwerdt]

A generic symbol decode for flex was now added with #2161

To decode a 1B two-bit to one-bit format use e.g., note that the symbols bits need to be MSB aligned:
symbol_zero={2}8,symbol_one={2}c

[zuckschwerdt]

For a payload format of 1C1C1C1C1C 1B1B1B1B 10 1S1S 1
e.g. 1011101110 10101110 10 1110 1 which is {25}bbabae8
you get {12}512 which is 010100010010:

rtl_433 -R 0 -X 'n=name,m=OOK_PWM,s=330,l=970,r=1200,symbol_zero={2}8,symbol_one={2}c' -y '{25}bbabae8'

The getters now would be:
get=@0:{5}:channel,
get=@5:{4}:button:[8:A 4:B 2:C 1:D],
get=@10:{2}:toggle:[2:ON 1:OFF],

[petterreinholdtsen]

There are two automated checks failing for this pull request. Perhaps it need an update?

[zuckschwerdt]

The goal is to make decoders like this easy as flex conf files. That way most users can tweak timings or adapt them for new devices.