Go Down

Topic: I want to build an autonomous GPRS weather station (Read 25533 times) previous topic - next topic

jumpjack

My major concern is instead receiving and decoding the RF signal.  :-?

aerozg

#31
Dec 18, 2010, 02:13 pm Last Edit: Dec 18, 2010, 02:14 pm by aerozg Reason: 1
Your 8110-AC-RX2 does the same thing as the RF Link 4800bps Receiver - 434MHz from SparkFun i was looking at: http://www.sparkfun.com/products/8950 - it's just a receiver.

The 8110-RTFSAW is a tranciever.

So yes, basically both will work.

To pick up and decode the signal form the anemometer and the rain sensor i will use the Freetronics 433MHz Receiver Shield: http://shieldlist.org/freetronics/433mhzreceiver

I will order one today and i hope it will work. I also found a Seeeduino V2.2 (Atmega 328P) board here in zagreb and bought it. i first thought to get a UNO board, but i didn't want to wait for it to long so i got this one instead. Should do fine i suppose. This is the board: http://www.seeedstudio.com/depot/seeeduino-v22-atmega-328p-p-669.html
This is the actual ad i got it from (a local calssifieds website): http://www.njuskalo.hr/elektronski-uredaji/arduino-clone-seeeduino-oglas-2092144

jumpjack

#32
Dec 18, 2010, 03:04 pm Last Edit: Dec 18, 2010, 03:09 pm by jumpjack Reason: 1
Looks like Auriol h13726 is identical to Ventus W155  and Hawa EWS 1500:

Hama EWS 1500:

http://www.mymemory.co.uk/Home-Gadgets/Hama/Hama-EWS-1500-Professional-Weather-Station




Ventus W155

http://www.ventusdesign.com/products/w155-weather-station-with-rain-gauge-and-anemometer/

aerozg

Yes, these kind of stations are manufactured by different companies under different brands/names.
Here's another one:

Meteoscan W155/W160

http://www.youtube.com/embed/ASFHcPo5EAs
http://www.verkkokauppa.com/popups/prodinfo.php?id=3435

jumpjack

If just for one of them would be available tech spec on transmission protocol!
Or if anybody had already reverse engineered one of them!  :-?

aerozg

#35
Dec 18, 2010, 04:00 pm Last Edit: Dec 18, 2010, 04:12 pm by aerozg Reason: 1
I don't really think this will be a big issue, we just have to see what others have done, i don't expect there to be much difference in the protocols used between this and other stations/sensors that work on 433.92MHz as they are pretty standard. Will have to read some more tho.

I guess we have identified the brands under which this same weather station is sold in different countries, and that is a good thing.

jumpjack

Great news!
Reading around on other forums, I found out that we do not even need a receiver! We can just connect the "official" receiver to PC through the audio board to be able to detect the signals and reverse engineer it!

This is the result for an Oregon Scientific sensor (TH138) I have (for another weather station):


I used this sensor because it only transmits temperature values and because somebody else already examined a sensor similar to this one:
http://alyer.frihost.net/thn128decoding.htm

Examining the Auriol sensors will be a bit more tricky as they transmit quite complex data:


Uploaded with ImageShack.us

I don't know which sensor(s) transmitted these data, as all of them were powered; it will be easy to grab just the udometer (by un-powering all the others), but it will be quite tricky to separate data for Temperature, Wind and umidity!  :-?

jumpjack

I tried with another sensor I have, a simple thermometer: it should be easier to decode... but I can't!
Can anybody help?
I highlighted values represented by the waveforms.



Uploaded with ImageShack.us

jumpjack

Ok, I got it:


Uploaded with ImageShack.us

Now I'll try with the station.

aerozg


Jonathan Oxer

@jumpjack: it looks like you're making great progress!

Would you mind providing some detail about how you connected the receiver to the sound card?
--
Jon
Arduino Shield List: http://shieldlist.org

jumpjack

I opened the receiving station, and  I located the receiver part: it's a small circuit physically separated from the main; it is connected through 3 wires, labeled as GND, PWR and (unreadable); of course I guessed (unreadable) was the signal.  ;)

So, I connected GND to GND of the earphone cable connected to PC, and SIGNAL to one channel of the cable.
Then I used Audacity to record "sound", using a MONO track: I had to determine by 2 random attempts which wire to connect to to get the signal recorded.
Then it was just a matter of sitting and waiting for signal bursts to come from the thermometer.  ;)

jumpjack

#42
Dec 21, 2010, 01:12 pm Last Edit: Dec 21, 2010, 01:13 pm by jumpjack Reason: 1
Quote
How is it working out for you?

Didn't yet have enough time to examine weather station data (they're very complex, and I seeone short signal every 30 seconds and one long and complex signal every 4 minutes, it's quite hard to figure out what's going on).
Besides, I'm not able to use the RX I bought to get the signals, I'm missing something... Isn't it enough to connect GND, VCC and RX oin these small devices?

aerozg

Very interesting stuff! I will try to replicate what you did and see if i can come up with anything. I noticed the LED on my anemometer assembly flashes red every 30 seconds, but i didn't know there is a signal sent every 4 minutes.

jumpjack

Weird thing is that not each led flash corresponds to a radio burst sent!  :-? Maybe it also indicates "data stored for further processing"?  :-?

The "4 minutes stuff" can also be guessed from the instruction manual, which says that first synchronization among sensor and base can require up to 4 minutes.  ;)

Go Up