Wifi protocol analyser

[OscarH]

Hi Great Sonsivri crew members

I'm looking for a tool to analyse/visualise any wifi data exchanged in between 2 devices.
Goal of my project is to replace a commercial weather receiver by my own receiver.
I have wind direction, speed and external temperature I'd like to monitor and archive (and eventually publish on Windguru).
Unfortunatley, I don't have the protocol available, so I would like to 'spy' the exchange and 'emulate' existing receiver with my own device.

Any suggestion on tools to be used ? A free version would be even better  .

Thanks  - OH
 

[kripton2035]

what is the brand/model of this weather station ?

[OscarH]

It is a Misol WS1040 weather station.
Now, I'm just wondering if the RF link between the main station and anemometer is Wifi or through a separate/proprietary protocol.
OH

[titi]

Hi OscarH,
this weather station works using the frequency of 433MHz.
So it is not in Wifi.

Generally they use a proprietary protocol but some time somebody do reverse engineering to decode they protocol.
This is usefull to intercept the temperature with by example an Arduino.
If you use SDR (Software Radio) it is possible to analyse the frame send by the transmiter:
http://labalec.fr/erwan/?s=sdr&searchsubmit=
https://www.rtl-sdr.com/tag/universal-radio-hacker/

This tool using SDR can decode a lot of Weather Station and other stuff (some time Weather Station use the same protocole, so even it is not exactly the same reference this tools may detect yours)
https://github.com/pm-cz/rtl_433

Hope this help ?
regards.

[Sideshow Bob]

I think the protocol can be downloaded from here
https://www.robotics.org.za/WS-WH24CP-1
What I think is going on is that the communication dongle is a 433 receiver with a serial to USB converter. Not knowing for sure in any way though. It is just my gut feeling

[devetka]

SDR is best way to go about it for all narrow channel communication like 433MHz, as mentioned already, but you might want to check this project too

https://github.com/aquaticus/nexus433

it uses digital 433MHz receiver that decodes ASK/OOK and you can use the output and decode the digital data if the weather station uses ASK/OOK (some do, not all). The project concentrates on the remote temp/humidity sensors but you can expand if your weather station uses that modulation.

[OscarH]

Titi, Sideshow Bob, and Devetka, this is changing the original approach I was thinking about.
Based on what I have seen in above posts, it looks like I can gather data from anemometer using an Arduino, store values and publish them on the web.
Still some job to be done, but I now foresee a way to do it.
Just looking for some spare time, as probably most of us 
OH

[Sideshow Bob]

Titi, Sideshow Bob, and Devetka, this is changing the original approach I was thinking about.
Based on what I have seen in above posts, it looks like I can gather data from anemometer using an Arduino, store values and publish them on the web.
Still some job to be done, but I now foresee a way to do it.
Just looking for some spare time, as probably most of us 
OH

Would it not be more easy to download data from the indoor tablet unit to a PC. Using the serial link built into the tablet module. Not that it is wrong in any way to do what you plan to do. 

[OscarH]

My plan was to remove completely the indoor tablet and collect directly the data from sensors.
The real reason is that information I need are not the one displayed on the tablet (typically max and min wind speed, average wind speed over a period of time, distribution of wind direction, etc...).
I'm a windsurfer/windfoiler and this is information I'm checking remotely before any trip to sea side.
I know this could be perceived as luxurious, but it is part of the fun side of the game :-)
OH

[Sideshow Bob]

My plan was to remove completely the indoor tablet and collect directly the data from sensors.
The real reason is that information I need are not the one displayed on the tablet (typically max and min wind speed, average wind speed over a period of time, distribution of wind direction, etc...).
I'm a windsurfer/windfoiler and this is information I'm checking remotely before any trip to sea side.
I know this could be perceived as luxurious, but it is part of the fun side of the game :-)
OH

Yeah I see. Your idea to use an Arduino sounds quite right for your use. You can get a lot of  433MHz modules for the Arduino, with code examples. And also if you want more shall we say realtime collection of data. Using a PC could be quite impractical. It is better to use some cheap module (like an Arduiono/ Raspberry Pi) for the collection of data. And just hook up the PC when needed. One thing you should perhaps look into is the memory capacity(RAM). Depending on how much data you need to store. It could be that an Arduino is somewhat limited regarding RAM capacity. Say you want store data every minute for 24 hours. 24*60 is 1440. And I will guess 16 bit is is needed for temperature and wind speed. That will say you need 4*1440 at least 5760 bytes of RAM at least. It could be that that a Raspberry Pi 4 or Raspberry Pi Zero module would be better choice. As those have more RAM and a SD card reader included.  

[darik]

Check "Universal radio hacker " - investigate wireless protocols like a boss   

https://github.com/jopohl/urh

[norkimo]

When reverse engineering some RF alarm devices I found some good success connecting a logic analyzer directly to appropriate traces on the PCB between the MCU and radio front end. You may consider it as well, and do the same on the transmission side. It's an easy way to get a very "clean" signal. Since you have physical access to the transceivers, it may be easier to take advantage of it.