Receiving weather station data on 915mhz

[drsprite]

Hi there,

I have a new weather station and it says that it broadcasts its data on 915mhz. I'm thinking I could use a moteino to receive this same data and then work on decoding it so I could create my own data logger. Does anyone know if I have my assumption correct?

Also, any references on how to do such a thing? I'm very curious, but not sure I could do it all on my own!

[syrinxtech]

Hi there,

I have a new weather station and it says that it broadcasts its data on 915mhz. I'm thinking I could use a moteino to receive this same data and then work on decoding it so I could create my own data logger. Does anyone know if I have my assumption correct?

Also, any references on how to do such a thing? I'm very curious, but not sure I could do it all on my own!

IMHO, you would have to take at least a few things into consideration:

1.  The exact frequency your weather station is using.  The 915MHz band is pretty wide and they might not be using exactly 915,000,000 Hz.
2.  Is the data encrypted?  If so, you would need the encryption key in order to decrypt the packets.
3.  How would you ever know if what you were receiving was in fact sent by your weather station?  I guess if you could verify that nothing within radio range was also using that band you could assume the sender was in fact the weather station.
4.  You would potentially have to do a lot of work to decode the packet format.  Is it simple ASCII text?  Or, structures containing a mixture of numbers, text, etc?  Have the numbers been encoded using some format (*10, *100, etc?)

[drsprite]

All great questions that I'm surely don't have an answer for Wonder if I should pick up a Moteino and start scanning?

I do own an rtl sdr antenna, and I do see some chatter in the 915 range (910-920mhz roughly). I guess I won't really know what's my specific station without scanning, and then taking the batteries out of it and see if i notice any drop in the chatter?

From what it looks like with the other DIYers intercepting weather station packets, I don't believe it's encrypted. I am only basing this off of the more expensive models aren't encrypting, so I don't think my cheaper model would.

[WhiteHare]

I do own an rtl sdr antenna, and I do see some chatter in the 915 range (910-920mhz roughly). I guess I won't really know what's my specific station without scanning, and then taking the batteries out of it and see if i notice any drop in the chatter?

Probably easiest is to put your RTL antenna right next to it, and then look for the highest power signature.

[drsprite]

Great idea, I'll have to give that a try.

Let's say I do get this working, I'd want to send this weather data into a database or something. Does Moteino have a wifi shield or ethernet shield that works with it? (Without having to cut RFM leads?)

I have a spare Pi, maybe a moteino on a Raspberry Pi? Is that possible? Then the Moteino gets the 915mhz packet, and I can have the Pi do whatever I want with it.

Just trying to think this whole concept through end-to-end.

[syrinxtech]

Great idea, I'll have to give that a try.

Let's say I do get this working, I'd want to send this weather data into a database or something. Does Moteino have a wifi shield or ethernet shield that works with it? (Without having to cut RFM leads?)

I have a spare Pi, maybe a moteino on a Raspberry Pi? Is that possible? Then the Moteino gets the 915mhz packet, and I can have the Pi do whatever I want with it.

Just trying to think this whole concept through end-to-end.

drsprite,

You have at least several options for connecting the Moteino to either 802.11 wireless or Ethernet (wired).  On the wired side you could use an ENCJ2860 or Wi5100 Ethernet board which connects via SPI to the Moteino.  On the 802.11 side you could use an ESP8266 (over a dozen varieties to choose from) which connects via the UART (TX/RX).

Another option is to connect the Moteino to a Pi using TX/RX.  In fact, Felix has already provided a great gateway software package which provides a web-based front end along with a back-end storage feature.  You could always choose another back-end database (MySQL, SQL, etc.) if you need more heavy duty database functionality.  Check out the PI Home Automation Gateway project:   http://lowpowerlab.com/gateway/

[WhiteHare]

@drsprite: Were you ever able to get it to work?  Assuming you've done your homework and you've confirmed that the weather station is using FSK, I'd suggest using Felix's example gateway code, setting promiscuousmode=true, using your RTL to gauge the center frequency and bandwidth of the transmissions, and then setting the pertinent RFM69 radio parameters accordingly in setup.  Then, let it rip and look for captured packets on the serial monitor.

[drsprite]

I haven't tried this yet, and am keeping it as an option for the future in case I get more adventerous.

As of right now I was able to connect the weather station's base station to another router, and use iptables to redirect the http packets to my web server. That way I can get the data I need pretty easily.

[kobuki]

@drsprite: can you please tell us the exact model of your weather station? Since almost all of them have a working DIY receiver solution, we'd be able to provide help more effectively.

[drsprite]

It's the Ambient Weather WS-1200-IP weather station. There's an indoor unit and an outdoor unit which both Tx to a device which has hard-wire Ethernet into the router. That device is called ObserverIP and is only capable of Rx.

Here's some FCC details which may help for those who want to venture with Rx'ing the packets.

Outdoor unit: https://fccid.io/WA5WH24B
Indoor unit: https://fccid.io/WA5WH25B

Both the outdoor and indoor units talk to the ObserverIP Rx unit. Most of the articles I've read (regarding other Weather Stations) say to disregard the indoor unit since it only adds barometer as useful information. Adding a barometer onto an Arduino/Moteino is easy enough.

I also took apart the ObserverIP unit, which I've uploaded all 12 photos here: http://imgur.com/a/10ZwL


I will admit that part of me still remains curious. If I add more sensors in the future (such as wet leaf sensor, etc., I could add it to a Moteino which will Tx to the Motino inside that's Rxing all this data). Then when the Moteino receives packet from the outdoor unit, combine it with the add-on sensors, and then I can submit 1 packet to all the various weather websites all at once, instead of out-of-sync timestamped readings.

[rinie]

Seems like an RFM23B-D module
On page 63 of the manual the layout of your picture is shown.

www.hoperf.com/upload/rf/RFM22B.pdf

Can I receive data from that module with an RFM69?