RTL_433 with Acurite 5in1

[Sean Jahnig]

Hi,

I'm a surfer/kitesurfer and as a hobby I build weather stations to help us know the conditions at local spots. My technical knowledge is limited and I only know what I read online in tutorials.

I have a few Acurite 5in1 weather stations spread around. I use raspberry pi's to intercept the signals using a generic RTL-SDR dongle. I use weewx with the necessary SDR driver to decode and broadcast the data to windguru. Generally, things work. However, there are some occasions where the SDR dongle will not see packets from the Acurite sensor. As far as I can tell, everything is plugged in and working, it's just that no packets are received. This could last for hours or days, and then fix itself after a matter of hours or days. At the same time, next to the rpi I have the acurite display which is showing a 4/5 bar signal being received from the sensor, so I know the sensor is there with a good signal. 

After some reading it seems like I need to calibrate the dongle? Is that right? Is there a code a can run to let the dongle scan all frequencies? I have this theory that as the dongle or sensor gets hotter during the day maybe the frequencies it's searching/broadcasting on is shifting slightly?

I have noticed the dongle gets hot and I've even tried to replace it with another dongle but it doesn't help. Would appreciate any suggestions on how I can scan frequencies.

Thanks,

Sean.

[Christian Z.]

If you add "-M level" and watch or log the "freq" key you should be able to observe the rough sender frequency as seen by the dongle.

It's always a good practice to observe the range and adjust the center frequency (-f) to a value somewhat in the middle.

You can also grab samples at different times with "-S known" and visualize on https://triq.org/pdv/ -- check that the signal doesn't go near the edges (top/bottom).

You could also widen the band by increasing the sample rate. Default for 433.92MHz is 250k, increasing to "-s 1024k" should work. The default for 868MHz is already 1024k using e.g. 2048k is not recommended:

Overheating the RTL-SDR is a function of sample rate and there is a good chance to damaged an uncooled RTL-SDR with high sample rates. Adding a heat sink could help.

[Sean Jahnig]

Thanks for the reply Christian,

Option 1, I ran "rtl_433 -M level" and after about 10-min it hasn't found anything.

Option 2, I found the command "rtl_433 -S all -T 120" which I ran and in 2 minutes it found 59 samples, 2 of which can be found here. I can open it on the website you mentioned but I don't know what I'm looking at - would you mind taking a look? Important to note that if I run "rtl_433 -S known -T 120" instead, it finds nothing.

Option 3, I tried "-s 1024k" for about 10-min but nothing was found.

Is there any basic process I could run to make sure the sdr dongle is performing correctly?

Is it normal for the sdr dongle to get hot? I need to try a heat sink.

Many thanks,

Sean.

[Christian Z.]

The sample files are empty / silent. You should see that noisy blue green background and red streaks from transmissions.

Perhaps try a frequency crowded with transmission, e.g. FM radio (somewhere in the 100M range) to check if the dongle works.

The chip will get too hot to touch, and that's not great. E.g. the NooElec SMArt with a metal case are better designed.

[allenm]

When you say "generic RTL-SDR dongle", I assume you mean something like one made by nooelec and not RTL-SDR.COM. I have several RTL-SDR.COM dongles and use them for Acurite sensors, my electric meter, security system, etc. They will run many months with no issues. However, I did buy a nooelec NESDR Mini a while back. My intent is not to bash nooelec, but I have to say rtl_433 fails to recognize it half the time on boot. The other issue I found was it crashes rtl_433 if I get my hands real close to it. I mainly use the nooelec for experimenting, since I can't rely on it for data logging.

[Sean Jahnig]

Hi Christian,

Thanks for the reply. I have tried that in the 100M range and I'm guessing this dongle is not working properly because it's not finding anything. I tried a few different frequencies. Below is the terminal output, please let me know if you see anything out of order. My guess is that it should not be that hard to get these dongles to work - and the signs are telling me that it's not working properly.

pi@raspberrypi:~ $ rtl_433 -f 95M -S all -s 1024k -T 120

rtl_433 version 21.05-60-g18d74de0 branch master at 202108070553 inputs file rtl_tcp RTL-SDR with TLS

Use -h for usage help and see https://triq.org/ for documentation.

Trying conf file at "rtl_433.conf"...

Trying conf file at "/home/pi/.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 161 out of 190 device decoding protocols [ 1-4 8 11-12 15-17 19-23 25-26 29-36 38-60 63 67-71 73-100 102-105 108-116 119 121 124-128 130-149 151-161 163-168 170-175 177-190 ]

Found Rafael Micro R820T tuner

[R82XX] PLL not locked!

Sample rate set to 1024000 S/s.

Tuner gain set to Auto.

Tuned to 95.000MHz.

baseband_demod_FM: low pass filter for 1024000 Hz at cutoff 102400 Hz, 9.8 us

[Sean Jahnig]

Thanks Allen,

This is interesting to hear. I have the nooelec nesdr v4 smart bundle from amazon, I've bought 3 of them. The first one was used in my first Acurite weather station which is here in the UAE and ran for about 2 years - I would say that it worked 90% of the time but the other 10% when it was offline, it was very irregular and I just could not find out why sometimes it would not receive packets - just had to wait a few hours for it to receive packets again. I had theories, like another device jamming the signal.. but I never proved it. It could be something as simple as the dongle getting too hot and then not working, or one of the issues you mentioned. I eventually replaced this station with a WeatherFlow Tempest which is now 100% online with no headaches.

I may take your advice and purchase an RTL-SDR dongle to see if it fixes my current problem. The problem may be heat, our country is very hot and despite the pi being in an ac room, it's still warm. Maybe long term exposure to warm temperatures affects this device. For sure the metal casing can almost burn you when you touch it - I have always noticed that.

[Christian Z.]

The metal cased SMArt from NooElec is a rather good one. The heat is spread over the whole body and shouldn't be a problem. The most generic ones, the plastic ones that look like the NooElec Mini are sensitive to a heat stroke.

I just double checked and while rtl_433 is not made for the FM audio transmissions it will trigger in the ~100M range. You should see some sample files with curving lines of signal.

If all this poor-mans debugging fails you need to take a live look at the signal and fiddle with stuff: frequency, sample rate, antenna, ...

You need to setup a more capable machine (Raspi is unlikely to work), then try one of SigDigger, CubicSDR, Gqrx, SDRangel.

[Jason White]

On Aug 21, 2021, at 2:11 AM, Christian Z. <chri...@zuckschwerdt.org> wrote:

The metal cased SMArt from NooElec is a rather good one. The heat is spread over the whole body and shouldn't be a problem. The most generic ones, the plastic ones that look like the NooElec Mini are sensitive to a heat stroke.

I'll second the metal-cased SDRs. I have three of the "Nooelec NESDR Smart v4 SDR"s and they don't need a fan. I've had others with plastic casings and they don't hold up to constant scanning applications. That being said they do occasionally (maybe every couple of weeks or so) get in to a weird state. Fortunately, this generates a particular error when this happens so I have a Perl program that watches the rtl_sdr logs for this strings and restarts rtl_sdr when this happens and it immediately fixes it.

-Jason

-- 
Jason White
jdw...@menelos.com

"The single biggest problem in communication is the illusion that it has taken place." - George Bernard Shaw

[Sean Jahnig]

@Jason, thanks for the input.

@Christian, thanks for the feedback and suggestions.

From what I understand, these SDR dongles don't generally give trouble. And considering the trouble I've had with it so far, I am feeling like it is not behaving as it should. If I go ahead and purchase an official RTL-SDR dongle and antenna set, is there any particular model you would recommend?

Thanks

[Sean Jahnig]

Another question, does the rtl dongle need additional power? like a powered USB hub? or is it ok to plug directly into the raspberry pi ?

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[Don Zcar]

It sounds like you just have a marginal  dongle.  I have a cheap E4000 2832 and I have run it for weeks at a time.  I've noticed that the frequency may drift about 100hz during warmup.  Can you just dial up an FM radio station and let it play continuously to see how that works?  Unless your power supply for your rpi is weak then just powering off rpi should be adequate.  Up till now I've used sdrsharp to do my listening to all kinds of signals.  Just started decoding weather stations and cars tire pressures as they drive by.  Do you have a pc you could plug it into to test it?

[Christian Z.]

> ok to plug directly into the raspberry pi ?

Always use a (short) extension cable to get the recevier away from the Pi, there will be noticable interference otherwise. Pi-rated power supplies should be able to handle one or more dongles.

 

dial up an FM radio station and let it play continuously to see how that works

That's good advice to see/hear frequency drift. Easier that to hunt for pilot tones (although I see pleanty of them in different bands here).

[Charles Beaudette]

Hi Sean and All,

I'm new to the group, but have been running genuine RTL_SDR and RTL_433 (as part of the IOTSensor project on RPi 4) with Acurite Atlas for a year reliably.  I've found working range to the RTL_SDR is less than with the Acurite display.  I think it's the wideband stubby antenna I'm using with the RTL_SDR.

Recommend you put your weather station within 5 feet of the SDR, see if the reliability problem is suddenly fixed.  Pretty easy to test. My Atlas is 100 ft away in the back yard and does get tot he SDR, but I had to turn the Atlas toward the west,  and put the SDR near a window, and now connection is 100% reliable. 

For heatsink, I took a piece of aluminum foil, crinkled it a little, wrapped and zip tied it around the SDR, to act as heatsink.  Super ghetto!

CB

[Christian Z.]

Hi Charles,

if you like, test the experimental "-Y autolevel" option in recent rtl_433. It should help with range (weak /shadowed signals).

[Sean Jahnig]

Hi Charles,

Sorry for the late reply.

Thanks for the reply and the suggestions. I have tried to place the station nearby and it doesn't make a difference. Overall I've had mixed luck with the AcuRite 5-in-1 and the RTL-SDR dongle on the rpi. Sometimes it works, sometimes it doesn't. Other times it half works where info is received but it's all zeroed out. There is no pattern that I can see to indicated where the problem may be. You can see the live station here where it is currently receiving, but zeros most the time https://www.windguru.cz/station/2014 Not sure if it's software or hardware related but it sure is frustrating.

I appreciate all the help and support that this group have given me. Sadly, I think I have lost interest in trying to understand what is going on. A few months ago I purchased a weather flow tempest station which has a proprietary base station that it connects to wirelessly. Currently I'm running a weewx driver on a rpi that intercepts the packets from the base station (via the same LAN) to it's manufacturers website. This has allowed me to achieve the same info being broadcasted to windguru. The station is more expensive but in the past 6 months since installing I have not seen it go offline at all. Eventually I will buy another one of these stations to replace the problematic AcuRite station.

Thanks,

Sean.

[cbad536]

Thanks

What does the -Y autolevel do?

[cbad536]

Very odd... if you're getting zeros in your data I would think you have a bad 5-in-1 unit.

Contact AcuRite, they sent me a new display free of charge, outside the warranty period.  They might just send you a whole new unit.

CB

[Christian Z.]

What does the -Y autolevel do?

 It automatically lowers the detection threshold to just above the calculated noise floor. From the preset -12 dB to around -25 dB usually.

[#LifeIsBetterOnTheBeach#]

Hi Sean im also playing around with RTL 433 and Helium Lorawan Windstations for Kitesurf spots. I startet with a friend last year to develope a Kitesurfer wind APP with wind push notifications. Could you forward some Winddata to our server to do some tests please. App IOS/Android you will find on www.heliumsmartworld.com my e-mail kund...@gmx.ch BR Martin