Acurite not so accurate on sunny days

[Tony Turner]

I have an Acurite 01525A1 connected by USB to an OrangePI ONE running Armbian Ubuntu Xenial and weewx v3.6.2. When the weather is cloudy the temperature seems to be relatively accurate compared to my old weather station and other stations close to me. But on really sunny days when the sun comes up over the trees (around 2 pm) my temperature starts to read high, it varies but lets say 6 to 8 degrees. I mounted it according to Acurite's instructions... 5 feet above the ground in a location that is clear of trees and other obstructions. I assume they intended for it to be out in the open where rain and wind will not be blocked. Anyway, it's impossible to know if the crazy little fan is working since I'm always at work when it messes up. I notice it because weather underground takes it down because of inaccurate date (I assume that's why it stops appearing on their map). Is there a way to correct this? Maybe based on the UV from the solar cell? Does anyone else have this issue?

Thanks,
Tony

[Tony Turner]

That should have said "data"... I hate auto correct!

[Craig Thom]

Not that I know of, although some people have added solar cells to make the fan in the 5-in-1 spin faster.

Since I'm using SDR, I've decided to remap temperature and humidity to be read from a different sensor (the lightning one, in this case).  I thought I had picked a good spot, but the temperature still spiked at around the time the sun would be shining in that area (just later than it did on the 5-in-1.

I am going to find another spot for it tomorrow. I may also buy or build a little enclosure for it.

[Thomas Keffer]

There's no a priori way to model the needed correction. You would have to install a thermometer that gives you the true in-the-shade, aspirated temperature, and leave it there for many months to build the model data you'd need for the correction. Then you could remove it. 

At the end of the day (or, in this case, in the middle of the day), there is no substitute for an accurate physical measurement. Otherwise, you're just adding noise. 

-tk

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[Tony Turner]

Well, that's disheartening. This station was a gift from my wife and I've tried every way I know of to make it accurate but there just doesn't seem to be a way. I have two consoles and neither of them agree on temperature, humidity or inside temperature. The weewx server seems to read the sensors directly and way more accurately than the Acurite consoles. I guess I'll have to buy another brand of weather station. Is there an inexpensive station that produces accurate output? Thanks for your help. 

Tony

[Thomas Keffer]

I wouldn't give up on your Acurite so quickly. In its price range, it's actually pretty good.

First, make sure your fan is working. Check it during a weekend, or ask a neighbor/wife to check it.

Second, make some sort of shade cover for it. Depending on the shape of the sensor, a white yogurt container with ventilation holes might work. Or, find something else that does fit.

Third, take a look at the WU siting guide. It has some good tips.

-tk

On Wed, Apr 12, 2017 at 6:23 PM, Tony Turner <tonk...@gmail.com> wrote:

Well, that's disheartening. This station was a gift from my wife and I've tried every way I know of to make it accurate but there just doesn't seem to be a way. I have two consoles and neither of them agree on temperature, humidity or inside temperature. The weewx server seems to read the sensors directly and way more accurately than the Acurite consoles. I guess I'll have to buy another brand of weather station. Is there an inexpensive station that produces accurate output? Thanks for your help. 

Tony

[Tony Turner]

Thanks Tom,
I'll spend some time this weekend and fashion some sort of shade for the unit. The temperature sensor is under unit supposedly in the shade with a fan that pulls air by it.... 5-1 units are crazy lol!.

The Ambient Weather stuff looks pretty good and very reasonable but I'm sure they have their issues also.

Tony

[Andy]

I bought the cover with the dual solar panels to help with the hot sunny days in the Sacramento area. First dual panel cover failed and they sent me an entire 5n1 with a dual solar panel after this post https://support.acurite.com/acurite/topics/outside-temp-to-high

The dual solar panel keeps the 5n1 closer to ambient, but not quite close enough. I am also using the SDR and a Honeywell sensor from Craigslist free section.

[Craig Thom]

Maybe my fan isn't running, since I've got the dual solar panel version.  I'll figure it out Sunday.

The sensor on my front porch must be getting some light around 6 pm, because it gets too high then.  Maybe I should figure out a way to get weewx to use the lower of the two temperature sensors to eliminate the sun problem.

[Tony Turner]

On Thursday, April 13, 2017 at 6:32:27 PM UTC-5, Andy wrote:

(snip) I am also using the SDR and a Honeywell sensor from Craigslist free section.

Maybe I'm just dumb but what is and SDR??

[Craig Thom]

Software Defined Radio.  The way I am using with weewx is with a USB tuner built for DVB-T TV broadcasts in other countries (but not the U.S.) that use the RTL2832U chipset.  People discovered that these tuners could cover a much larger range than DVB-T and have been using them for receiving all kinds of stuff, including the 433 MHz signals used by wireless weather sensors (and a lot of other stuff in the home).

rtl_sdr handles controlling the radio, and rtl_433 decodes packets from known devices.  The weewx sdr driver uses rtl_433 to get the packets of information directly from the weather sensor.

The radio receivers are available for $10-$20 all over the place online.  Since they were intended for TV in other countries the antenna connection is often unusual, but that doesn't matter if you are using the antenna that comes with it.

My antenna is a monopole, so it needs to be sitting on a piece of metal to work best.  It's magnetic, so I've just got it stuck to the side panel of an old computer.

[Tony Turner]

Craig that sounds pretty interesting. I assume this should be another topic because I want to know more about the SDR. I have a very old Acurite unit that does not have a USB interface but it's REALLY accurate. It would be nice to be able to intercept the signal and use it with weewx. I assume you find the frequency the sensors are transmitting and somehow tell the WeeWx driver to use those signals??? If you don't mind sharing how all that works I'd love to know>

Thanks,

Tony

[Craig Thom]

The weewx driver is here: https://github.com/matthewwall/weewx-sdr

I don't think it's complete, and there were some things I had to work out, but you can search for the answers here.

One thing to keep in mind is that the pressure sensor for my Acurite system, and probably all the others, is in the display.  If you bypass the display, you'll have to find another source for pressure.

rtl_sdr is the Linux driver for the radio, and rtl_443 receives and decodes the transmissions from the sensors.

http://www.rtl-sdr.com/ has general info on using sdr receivers based on the RTL2832U chip, which I guess is intended to be used for direct digital TV broadcasts in other countries.  That means the radio and antenna you buy on ebay probably comes with TV watching software that will NOT work in the U.S.

But once you've got the radio and the software installed, it's all a matter of tweaking it to get it working.

[Tony Turner]

Craig, I'm very interested in trying this. My wife told me yesterday that she has bought me an Ambient Weather 900 IP Observer since my Acurite is not working the way it should. I'm not sure about the Ambient Weather unit but I do know it only uploads to Weather Underground which means it won't upload to my website like WeeWx does... totally unacceptable. I may just try to setup the SDR thing to use with my WeeWx server. I didn't want to spend any more money on any of this because it's just a tiny little hobby for me and I've already spent more than I intended. I guess it would be worth $25 to see if I can make it work. Oh well! at least it's not a bass boat lol!

[mwall]

On Wednesday, April 19, 2017 at 4:08:26 PM UTC-4, Tony Turner wrote:

Craig, I'm very interested in trying this. My wife told me yesterday that she has bought me an Ambient Weather 900 IP Observer since my Acurite is not working the way it should. I'm not sure about the Ambient Weather unit but I do know it only uploads to Weather Underground which means it won't upload to my website like WeeWx does... totally unacceptable. I may just try to setup the SDR thing to use with my WeeWx server. I didn't want to spend any more money on any of this because it's just a tiny little hobby for me and I've already spent more than I intended. I guess it would be worth $25 to see if I can make it work. Oh well! at least it's not a bass boat lol!

tony,

you can use the weewx-sdr driver to capture signals directly from your acurite sensors.

you can also use the weewx-sdr drive to capture signals directly from the ambient (fine offset) sensors.

in fact, you can use a single sdr with one instance of the weewx-sdr driver to capture data from both the acurite and fine offset hardware at the same time.

or you can use the weewx-interceptor driver to capture the tcp/ip traffic from the ambien observer (which is a sensor-to-internet bridge)

m

[Tony Turner]

M,

That is way cool!! I can let the Ambient upload to Weather Underground and I'll capture the sensors and use that with WeeWx to upload to my website. The SDR hardware looks pretty cheap. Would something like this work? https://www.amazon.com/Receiver-RTL2832U-Low-Cost-Compatible-Packages/dp/B015DN4DP6/ref=sr_1_5?ie=UTF8&qid=1492459242&sr=8-5&keywords=sdr+radio 

[Tony Turner]

M, 

I missed the last part when reading this on my phone but the intercept driver looks like the answer to my issue if I'm using the Ambient 900. Heck... I'll give my Acurite to my daughter to use out on their farm win-win lol!

You guys are so smart!! Thank you for your help.

Tony

On Wednesday, April 19, 2017 at 3:21:57 PM UTC-5, mwall wrote:

(snip)

[Tony Turner]

BTW! I have checked my 5-1 units fan to see if I can hear it running but I hear nothing.... I checked it Saturday and Sunday in bright sun light and a very warm day and never heard a thing. I have to assume it's not working. I received this unit for my birthday back in November but didn't get around to installing it until February. I would have thought it would work longer than that.

Just as a side note. I have been looking at the weather stations around me on weather underground and found one other Acurite 5-1 unit. I found it because I noticed one temperature that was the same as mine so I looked at what station hardware they were using... same as mine. It was easy to spot because my station and theirs was reading 8 degrees higher than any of the other stations around us. He seems to be having the same issue.

[Chris Swanda]

Tony,

On my 5-1 unit, spiders will crawl up under the unit and build webs, that in turn will stop the fans from spinning.  Or at least on mine, that has happened in the past.  

From the Acurite website.

Step 1.
Remove the four outer screws on the bottom of the sensor. Keep the screws for re-assembly. 

• Note: Be careful not to remove or adjust the rain calibration screws located beneath the rain gauge.

Step 2. 
Separate the upper and lower halves of the sensor. 

Step 3.
Check the fan for debris, such as insects or spider webs. A gentle puff of air can clear most obstructions safely

If no debris appears to be blocking the fan, position the top white portion of the sensor (that has the solar panel) in direct, bright sunlight. The fan should power on immediately without any assistance (such as a nudge). Note: Artificial light, such as flashlights, cannot be used as a substitute for actual sunlight. Also, overcast days may not be sunny enough to power on the fan.

Step 4.
To reassemble the sensor, bring the two halves of the sensor back together. 

Step 5.
Reinstall the four outer screws to join the upper and lower portions of the sensor together.

[Tony Turner]

Thanks for the information Chris. I've kind of committed to replacing the unit since my wife bought me another one but I'll check all that before I send it to my daughters house.

Tony

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[Cari Podesta]

I have the 01525 and after 1 year the outside temp(always)reads -40 even when its near 80F. All other readings in or outside are good; rain, wind etc. I reset to factory defaults, replaced both sender and receiver batteries. Anybody have any ideas other than buying a new sender?

Thanks,

cari