Getting all the bits working together

Over the years I have tried to get my Oregon Scientific weather station to work a couple of times.  And I've given up a couple of times.  Most recently I thought I had everything working properly, hooked it all up at the bottom of the garden and connected it to a raspberry pi running weewx.

But I realised that the WGR800 wind sensor (anemometer) wasn't reporting anything.  As in . . . it didn't seem to be connecting at all.  I finally got around to bringing it all back in the house and sitting on the desk here beside me to see if I could work out what was going on.

I wanted to check out whether the device was sending a radio signal in the first place.  If it's not transmitting, then of course the base station can't receive anything.  Using my RTL-SDR dongle I was able to pick up a signal from the PCR800 (temperature and humidity sensor), but saw nothing from the WGR800.

In true IT Crowd fashion, I tried turning it off and back on again.  Nothing.

I tried replacing the batteries.  Nothing.

I tried putting the batteries in upside down in case the sticker showing the polarity was wrong.  Nothing.

Then I put the batteries back in again and, as if by magic, it started working again.

As much for my own sanity as for anything else, here's the evidence that both devices are transmitting at the same time -

rtl_433 -R 12 -M bits -M level -M stats:3 -M bits 
rtl_433 version unknown inputs file rtl_tcp RTL-SDR SoapySDR
Use -h for usage help and see https://triq.org/ for documentation.
Trying conf file at "rtl_433.conf"...
Trying conf file at "/usr/local/etc/rtl_433/rtl_433.conf"...
Trying conf file at "/etc/rtl_433/rtl_433.conf"...
Registered 1 out of 149 device decoding protocols [ 12 ]
Found Rafael Micro R820T tuner
Exact sample rate is: 250000.000414 Hz
[R82XX] PLL not locked!
Sample rate set to 250000 S/s.
Tuner gain set to Auto.
Tuned to 433.920MHz.
Allocating 15 zero-copy buffers
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
time      : 2021-xx-xx 20:33:08                    brand     : OS
model     : Oregon-WGR800 House Code: 33
Channel   : 0            Battery   : 1             Gust      : 0.0 m/s       Average   : 0.0 m/s       Direction : 0.0 degrees
Modulation: ASK          Freq      : 434.0 MHz
RSSI      : -0.1 dB      SNR       : 26.6 dB       Noise     : -26.7 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
time      : 2021-xx-xx 20:33:22                    brand     : OS
model     : Oregon-PCR800 House Code: 55
Channel   : 0            Battery   : 1             Rain Rate : 0.8 in/h      Total Rain: 0.2 in
Modulation: ASK          Freq      : 434.0 MHz
RSSI      : -0.1 dB      SNR       : 27.1 dB       Noise     : -27.2 dB
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
time      : 2021-xx-xx 20:33:31                    enabled   : 1             frames    : 
count     : 4            fsk       : 0             events    : 2             stats     : 
device    : 12           name      : Oregon Scientific Weather Sensor        events    : 4             ok        : 2
messages  : 2            abort_early: 2
I added in a couple of extra switches to the command line to make things easier to read -
-R 12 --> only decode or display protocol 12 - Oregon Scientific devices
-M bits --> show the bits apparently, but I haven't seen difference between including and not including this value
-M level --> show the signal levels (yellow above)
-M stats:3 --> show statistics at the end

Tell me about this 433MHz stuff

As indicated in my earlier post, the reason I got the SDR in the first place was because I wanted to see if I could pick up the signals between different elements of my weather station.  It turns out that this is a lot easier than I had hoped.

Download and run the application rtl_433.  It takes care of a whole load of stuff that I thought I would have to write by hand.

Here's a few of the things it picked up straight away -

  • My Oregon Scientific rain meter - reporting recent rain (0.0) and total recorded to date (3.0)
time      : 2021-xx-xx 21:25:14                    brand     : OS
model     : Oregon-PCR800 House Code: 201
Channel   : 0            Battery   : 1             Rain Rate : 0.0 in/h      Total Rain: 3.0 in
  • A meat thermometer that is sitting in a drawer downstairs, sending out the (wrong - 320.0) temperature every 10 seconds or so.
time      : 2021-xx-xx 21:16:16
model     : Thermopro-TP11                         Id        : 232
Temperature: 320.0 C     Integrity : CRC
  • Somebodys car.  I don't own a Toyota.
time      : 2021-xx-xx 21:16:09
model     : Toyota       type      : TPMS          id        :xxxxxxxx
status : 128 pressure_PSI: 29.750 temperature_C: 8.000 mic : CRC
  • Another Toyota.  This one is recording a different pressure, temperature and id
time      : 2021-xx-xx 21:30:19
model     : Toyota       type      : TPMS          id        :YYYYYYYY
status : 131 pressure_PSI: 30.750 temperature_C: 13.000 mic : CRC
  • One of a selection of temperature probes I have about the house
time      : 2021-xx-xx 21:28:29
model     : Nexus-TH     House Code: 29
Channel   : 1            Battery   : 1             Temperature: 18.40 C      Humidity  : 50 %
  • I don't know what this one is yet, but whatever it is has 4 buttons and they are all set to on.  A quick search on HCS200 tells me that this is a channel hopping controller.  It may be from a smart home remote controller, but is probably for something more basic like a car door remote control.
time      : 2021-xx-xx 21:31:52
model     : Microchip-HCS200                       id        : 0FFFFFFF
encrypted : FFFFFFFF     button1   : ON            button2   : ON            button3   : ON            button4   : ON            misc      :               battery_ok: 0
 

So, how does it work?

$ /usr/bin/rtl_433
rtl_433 version unknown inputs file rtl_tcp RTL-SDR SoapySDR
Use -h for usage help and see https://triq.org/ for documentation.
Trying conf file at "rtl_433.conf"...
Trying conf file at "/home/xyz/.config/rtl_433/rtl_433.conf"...
Trying conf file at "/usr/local/etc/rtl_433/rtl_433.conf"...
Trying conf file at "/etc/rtl_433/rtl_433.conf"...
Registered 122 out of 149 device decoding protocols [ 1-4 8 11-12 15-17 19-21 23 25-26 29-36 38-60 63 67-71 73-100 102-105 108-116 119 121 124-128 130-149 ]
Found Rafael Micro R820T tuner
Exact sample rate is: 250000.000414 Hz
[R82XX] PLL not locked!
Sample rate set to 250000 S/s.
Tuner gain set to Auto.
Tuned to 433.920MHz.
Allocating 15 zero-copy buffers
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time      : 2021-xx-xx 21:05:52
model     : Thermopro-TP11                         Id        : 232
Temperature: 320.0 C     Integrity : CRC
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time      : 2021-xx-xx 21:05:53
model     : Nexus-TH     House Code: 100
Channel   : 2            Battery   : 1             Temperature: 20.10 C      Humidity  : 48 %
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time      : 2021-xx-xx 21:06:04
model     : Thermopro-TP11                         Id        : 232
Temperature: 320.0 C     Integrity : CRC
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time      : 2021-xx-xx 21:06:16
model     : Thermopro-TP11                         Id        : 232
Temperature: 320.0 C     Integrity : CRC
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time      : 2021-xx-xx 21:06:28
model     : Thermopro-TP11                         Id        : 232
Temperature: 320.0 C     Integrity : CRC
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time      : 2021-xx-xx 21:06:34
model     : Nexus-TH     House Code: 208
Channel   : 3            Battery   : 0             Temperature: 19.00 C      Humidity  : 57 %
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
time      : 2021-xx-xx 21:06:38
model     : Nexus-TH     House Code: 29
Channel   : 1            Battery   : 1             Temperature: 18.50 C      Humidity  : 50 %

What is this SDR you speak of?

I'm more of an I.T. guy than an R.F. guy, so my knowledge of things radio-y is very limited.

My very basic understanding of radios doesn't go much further than a little diagram showing an aerial on one side, a box in the middle and a speaker on the other side.  Magic happens inside the box and the radio waves on one side end up as sound waves on the other side.

While trying to work out how I could pick up information being broadcast by my weather station on 433MHz, I came across this video which introduced me to the concept of a USB SDR receiver.  I found this site which sold the USB dongle, aerials and assorted bits and pieces for $35.  A bit of research showed that this was a popular and well supported one so I went ahead and bought it.  It arrived from China about two weeks later.

It was then that I realised I didn't know what to do with it.

I reckoned that I would watch some more YouTube videos and find out from there.  It turns out that the presenters in most of the videos I watched, while very knowledgeable and technical, skipped over some of the bits that are essential for a total beginner.  I'm going to cover some of these in this post.

First challenge - tune into a local radio station.  For ease of explanation I'm going to use a station called Q102 which broadcasts on 102MHz.

  1. Plug in the dongle.
  2. Connect an aerial.  I have no idea what is the correct one to use so I just connected the two long ones that came with the dongle.
  3. Fire up GQRX and tune to 102.000.000
  4. Turn down the volume because all I can hear is static

I can see from the waterfall that there are two strong signals either side of 102.  One is at 101.8 and the other is at 102.2.

  1. Click on one of the peaks in the upper part of the display to tune into that specific frequency
  2. Still static
  3. Select the "Receiver Options" panel on the right and set the mode to "WFM (stereo)" or "WFM (mono)"
  4. Music

In summary, you need the USB dongle plugged in to your computer, you need an aerial plugged in to the USB dongle, receiver options set to "WFM" and the tuner set to whatever wavelength your favourite local station broadcasts on.

  • SDR = software defined radio.
  • R.F. = radio frequency
  • Waterfall = a representation of the signals received over time.  In this example, it's the mostly yellow block with the two red bands down the middle.

A blast from the past

29/11/2002.  My god, it's full of . . . people.

So, 8 weeks later I get around to posting the first update. I'm not sure what to write since it's all old news by now, but I guess a quick summary of what has happened so far might be in order.

We set off from Dublin airport on October 1st, spent two weeks in Japan and then flew to New Zealand and spent the next 6 weeks touring around there. We are now facing the hard part of the trip - getting a job and finding somewhere to live.

Some of the best bits so far have included much of Japan even though it was very tiring and hard going, also walking with the tweenies up to the face of a glacier. Some of the worst bits have included side-swiping the camper off a bollard in a petrol station and being told that our excess luggage was going to cost us something like EUR3,000. We eventually wangled it down to EUR400 or so.

Japan wasn't as expensive as we had been expecting - it was perfectly possible to eat in a restaurant for the equivalent of EUR6 for lunch. This is due to the huge number of noodle bars and tonkatsu (deep-fried pork) joints in central Tokyo. We ate out almost all the time and rarely had to pay more than we would pay at home for lunch. In fact, when I think about it, I'm not sure that I could get lunch anywhere at home for that price.

There is much good value to be had in Japan, and one thing that is very usefull to remember is the luggage delivery service which is offered certainly at Narita and presumably also at Kansai and the internal airports. When you remember that the mass transit systems in Japan aren't really designed for transporting luggage this makes even more sense. This appears to be a little secret that the Japanese keep to themselves by the cunning trick of not publicising it in any language other than Japanese. We sent our two heaviest bags direct to the last hotel we were going to visit in Japan, having packed them with stuff we knew we weren't going to need until New Zealand. Cost something like EUR15 or so per bag. A real bargain, considering that one of the bags weighed over 40kg and the second one wasn't far off. Of course it helps to notify the hotel that you are sending stuff ahead so they don't blow your bags up or refuse to accept them. We also sent two small bags to the apartment we were staying in for the first few nights. Same cost, even thought the two small ones were going to Tokyo and the two huge ones were going to Osaka. It helps to have your address pre-written, preferably in Japanese as you don't want to have your bags getting lost with a return address 5,000km away. You just go up to the desk, give the people your bags with the address and they give you a receipt while apologising for the fact that it will be an early-next-morning delivery to a different city and handing your children loads of cute Japanese toys.

Did I say the transport systems weren't designed for luggage ? Let me tell you a story about our trip to Haneda airport. This is the 'internal' airport for Tokyo, in that this is the airport which connects Tokyo to the rest of Japan, while Narita serves the connections to the rest of the world. It is served by a handy monorail from Tokyo. We were staying in a ryokan which was two subway stops away from the start of the monorail. Easy, huh ? I don't think so. Even though the monorail is elevated (aren't they all ?), there are *no* lifts in the station, and getting from the ground to the train involves about 4 escalators. Remember, this is an airport connection. People (well, the non-Japanese) bring luggage to airports. Lifts are a handy way of getting your luggage from the ground floor up to the train. Still with me. It seems like a crazy way to design an airport connection, until you remember that the Japanese all use the luggage delivery services I wrote about above. They don't carry their bags with them, so it's not an issue.

I said above that we stayed in a ryokan in Tokyo. It was an interesting experience, and certainly one which is worth a try. A ryokan is basically the Japanese equivalent of a business hotel in that it is (was) where Japanese people who were on the road would stay for a night. It provides a bed, a shared bathroom and possibly shared breakfast in the morning. And that's it. No frills, but you don't need frills. Some of the travel books talk about the rules and regulations which must be followed when staying at a ryokan, but in my experience the standard ones for any Japanese building apply - take your shoes off at the entrance and do what the momma-san says. One of our big worries was how the paper-thin walls would survive our kids, but this wasn't a problem. Although the room looked pretty it was obviously designed to withstand a certain amount of wear and tear, so this wasn't really a problem. Now, if you were to go to some swish 17th century ryokan with all sorts of royal connections and history I'm sure you would run the risk of doing some damage, but in a regular down-town one don't worry.

One thing to watch out for is the fact that the Japanese have developed a knack of hiding buildings. In many countries around you the world you can see from a distance that this building is a railway station because of the huge train logo on the front and the set of railway tracks going into it. You can see that this building is a department store because of the models and price tags in the windows. Not so in Japan. They seem to hide all sorts of things behind the most peculiar facades. Forget about finding something armed with a map, an address and logic - it just doesn't work here.

It also seems that the Japanese haven't grasped the concept of 'across the road' as in the bus stop you want is across the road. They also haven't got the hang of drawing good maps either. If you are ever trying to follow a Japanese map, make sure you have at least two points of reference that you can relate to before heading off or you will be lost before you know it.

That's enough about Japan for the moment. More later. If anybody wants, they can email me at. If you don't know my name then I hope you found this interesting, but I don't want to encourage spam, so if you send mail to log at the above domain I will get it eventually.

Hope all is well at home and regards to everyone out there.