[CplJonlan]

Hi all,

I bought the aforementioned temperature + humidity "weather station" from Lidl for about 20 euros. As the supplied receiver reads remote data very seldom, I decided to see if I can make heads or tails of the data sent by the sensors.

Data is transmitted with 433 MHz RF signal in bursts which consist of 9 copies of data packets.
Data packets contain one sync pulse (~4500 useconds) + 36 bits (0 = ~1500 usec, 1 = ~2500 usec).
My Arduino code can reliably decode the data by checking for above pulse lengths ±50 usec, using either cheap MX-RX-5V or more expensive RXB6 receiver.
 

Code:

S rrrrrrrr b m id tttttttttttt ffff hhhhhhhh

    S  sync pulse (missing from the first packet)
0..7    r  random id (changes every reboot)
8    b  battery (1 = ok, 0 = low)
9    m  manual tx (1 if manual)
10..11    id numeric id 0..3 (only 0..2 used)
12..23    t  temperature (binary, 0.1 ℃)
24..27    f  filler bytes (1111)
28..35    h  humidity (binary)

I have yet to put a sensor in a freezer to see how negative temperatures are encoded (and whether the temperature really uses all 12 bits)

[werk_ag]

Hi CplJonlan,

You may try something like this:

Code:

// Calculate negative temperature
if ((AuriolOutTemp & 0x800) == 0x800) AuriolOutTemp = AuriolOutTemp | 0xF000;

[CplJonlan]

Thanks, that did it. I got 3913 as a temperature for -18.3 degrees Celsius. When converted to hexadecimal, that's 0x0f49 and when sign-extended to integer it's 0xff49 ie. -0x00b7 which is -183 in decimal.

I put my findings here with some extra notes in case someone wants to use the sensor modules in their project.

[Nunu00]

Hi all,

I bought the aforementioned temperature + humidity "weather station" from Lidl for about 20 euros. As the supplied receiver reads remote data very seldom, I decided to see if I can make heads or tails of the data sent by the sensors.

Data is transmitted with 433 MHz RF signal in bursts which consist of 9 copies of data packets.
Data packets contain one sync pulse (~4500 useconds) + 36 bits (0 = ~1500 usec, 1 = ~2500 usec).
My Arduino code can reliably decode the data by checking for above pulse lengths ±50 usec, using either cheap MX-RX-5V or more expensive RXB6 receiver.
 

Code:

S rrrrrrrr b m id tttttttttttt ffff hhhhhhhh

    S  sync pulse (missing from the first packet)
0..7    r  random id (changes every reboot)
8    b  battery (1 = ok, 0 = low)
9    m  manual tx (1 if manual)
10..11    id numeric id 0..3 (only 0..2 used)
12..23    t  temperature (binary, 0.1 ℃)
24..27    f  filler bytes (1111)
28..35    h  humidity (binary)

I have yet to put a sensor in a freezer to see how negative temperatures are encoded (and whether the temperature really uses all 12 bits)

Hi, I recently bought the same weather station too and I'm interested in connecting the sensors to arduino. The problem is that I'm not very good at writing the code to decode the data and so I wanted to ask if you could post your arduino code.
Thank you

[werk_ag]

Hi Nunu00,

Welcome to the forum.
I think CplJonlan doesn't visit the forum since some time. Try send him a Private message, so he will be notified of your request.

Rgs.
Werk_AG

[CplJonlan]

Hi,

I put the code here - I hope it works as it's part from a test program which reads multiple sensors. If everything still works I didn't remove TOO much code

Let me know if you have any trouble with it and I will take a look (after holidays).

[vesat]

Hi,

I put the code here - I hope it works as it's part from a test program which reads multiple sensors. If everything still works I didn't remove TOO much code

Let me know if you have any trouble with it and I will take a look (after holidays).

Hi,
Thanks a lot for the fine working code! It saved me lot of time.
The sensors work surpisingly well from inside fridge etc.

[Nunu00]

Hi,

I put the code here - I hope it works as it's part from a test program which reads multiple sensors. If everything still works I didn't remove TOO much code

Let me know if you have any trouble with it and I will take a look (after holidays).

First thanks for the code, it works perfectly even on an esp8266.
For some time, however, I've been trying to make the code compatible with homeassistant but there's no way to get it compiled. Has anyone succeeded? Or do you have any advice on how to try to fix it?

[uncle_bob]

Hi,

I put the code here - I hope it works as it's part from a test program which reads multiple sensors. If everything still works I didn't remove TOO much code

Let me know if you have any trouble with it and I will take a look (after holidays).

First thanks for the code, it works perfectly even on an esp8266.
For some time, however, I've been trying to make the code compatible with homeassistant but there's no way to get it compiled. Has anyone succeeded? Or do you have any advice on how to try to fix it?

Hi Nunu00,
I get my weather data into Home assistant by using CumulusMX and it's MQTT function.
It would be pretty awesome if the Weatherduino could run in ESPHome (which is now integrated into Home Assistant) , but I'm unsure if it's even possible.