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Weather Software => RaspberryPI Weather Software => Topic started by: miraculon on October 03, 2015, 08:48:17 AM

Title: SD card flash life on Wx programs using Raspberry Pi
Post by: miraculon on October 03, 2015, 08:48:17 AM
I just replaced my SD card after experiencing problems with GUI log-in, graphs, HTML displays and general malaise with the meteohub based system. With the new SD card, everything is working as it should.

This was about a year and a half of operation. Meteohub is handling the data from several ISSs. I don't know if this puts more wear and tear on the flash than a simple single weather station system or not.

Has anyone else had to replace their SD card on their RaspPi yet? I also had another unit out in the garage that ran a camera and some PiFace utilities previously. This unit has been repurposed for another meteohub station monitoring a VUE console.

I found some "industrial grade" SD cards, especially the Panasonic one with SLC-lite technology.

They claim:
Quote
The QE Series adopts MLC NAND flash memory with "SLC (Single Level Cell) Lite" access mode that provides higher endurance, data retention and power fail robustness than standard MLC products. An extended operating temperature
range of -25°C to +85°C is suitable for various applications. The integrated enhanced controller ensures long lifetime use and high system performance. Quality is maintained with 100% product screening before shipment to achieve low
failure rate. Storage capacity options include 4GB, 8GB and 16GB models

The true SLC SD card is $253, so that is too much. The SLC-Lite 16GB is $63, which is almost twice what the Pi board costs! If I have to go through this SD card replacement excercise again, I just might try it anyways.

Greg H.
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: Bushman on October 03, 2015, 09:06:23 AM
I am moving all my Pis to USB stick OS.  http://myblog.furnissathome.co.uk/?p=384
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: miraculon on October 03, 2015, 09:37:51 AM
Thanks for the tip and link. It seems that SD card corruption is common on the Pi. Fundamentally, though, the USB stick could suffer from the same issue couldn't it? The USB sticks have flash memory that is accessed via USB instead of the SD card's interface.

I found this on Wikipedia (although I was aware of the read/write life issue before):
Quote
Longevity

The memory in flash drives is commonly engineered with multi-level cell (MLC) based memory that is good for around 3,000-5,000 program-erase cycles,[45] but some flash drives have single-level cell (SLC) based memory that is good for around 100,000 writes. There is virtually no limit to the number of reads from such flash memory, so a well-worn USB drive may be write-protected to help ensure the life of individual cells.

Estimation of flash memory endurance is a challenging subject that depends on the SLC/MLC/TLC memory type, size of the flash memory chips, and actual usage pattern. As a result, a USB flash drive can last from a few days to several hundred years.[46]

Regardless of the endurance of the memory itself, the USB connector hardware is specified to withstand only around 1,500 insert-removal cycles.[47]

This Multi-Level Cell memory may be the Achilles heel of running weather programs on the Pi.

With "3,000-5,000 program-erase cycles" as the life for MLC, using a RPi for a weather program sounds doomed from the start...

Maybe a USB HDD might work? Or maybe I will just treat it like my Davis DFARS fan, just part of an annual ritual..

Greg H.
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: Bushman on October 03, 2015, 11:49:03 AM
I've read that about USB but I can tell you I have NEVER experienced a USB stick failure.  SD cards OTOH....  (never buy Kingston BTW).  An HD or an SSD would definitely work.  But they cost much more than the Pi itself (for a large one)  I was looking  at making a Pi into a NAS; could run the OS and the storage of the same drive.  BTW, you should clone whatever you use so that downtime is minimized.
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: Bushman on October 03, 2015, 12:04:34 PM
https://learn.adafruit.com/external-drive-as-raspberry-pi-root/overview
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: nincehelser on October 03, 2015, 02:31:58 PM
I had problems early on due to voltage drops during writes.  Once I learned to use a more beefy power supply, my problems went away.  In other words, some generic cell-phone power adapters are just too wimpy for use with the Pi, especially if you have power-hungry devices attached to the USB ports.

Quality SD cards (actually all better flash-based devices) use wear-leveling algorithms, so it's typically not a huge concern.  The bigger the memory, the more the wear gets spread out.

I used to deploy USB flash drives by the hundreds at a time.  Once I got a generic lot that was extremely susceptible to "bit rot".  You'd could write data to them and verify that it was correct, but within a few days they would just randomly corrupt while sitting idle.   Fortunately I haven't seen that same problem for a long time.
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: miraculon on October 03, 2015, 03:29:08 PM
Quote
a more beefy power supply

How much beefiness should I be looking for? 2A, more? What did you end up with for sufficient write/erase current from the USB supply?

I would appreciate knowing a good value, so I don't have to reinvent the wheel....

Greg H.
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: weatherc on October 03, 2015, 03:56:05 PM
I runned a Pi on my remote station first running WeeWx. It just caused problems all the time, all kind of odd crashes and hangups. Then i put few more bucks to the show and bought a "Pi-cousin", Cubieboard Cubietruck and a 32 G SSD as external disk and no issues since that. Re poweusage, that combo uses ca 1 watt (0.2 A) as average.

In addition to collecting the weatherdata from the VP2 it also grabs/manage the IP-cam image (reduce its size, adding wxdata on it + uploading the pic) and collecting and uploading data from the solarpanel controller.
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: nincehelser on October 03, 2015, 03:57:01 PM
Quote
a more beefy power supply

How much beefiness should I be looking for? 2A, more? What did you end up with for sufficient write/erase current from the USB supply?

I would appreciate knowing a good value, so I don't have to reinvent the wheel....

Greg H.

1.8A is recommended for a Pi2.  You can get by with less, though.  It just depends on what other things you have hooked up.

When I was having problems with my original Pi, I was running an old adapter of about 0.5A.  The old wifi adapter I was trying to use was also a major power hog.  It was not a good mix.

This link give more detail: https://www.raspberrypi.org/help/faqs/#powerReqs


Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: miraculon on October 03, 2015, 04:49:15 PM
Thanks.

I am pretty sure that I got the power supply as part of a RPi starter kit. I'll check it the next time I power it down, since I think the current rating is on the 120V plug side and I can't see it right now.

I think that I either got the PS with the RPi as part of a kit, or ordered it at the same time with the PS being recommended.

Greg H.
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: dashforecast on February 23, 2021, 01:08:04 PM
Hi,

I agree that the cost of the industrial SD cards recommended for this purpose can sway the balance on whether this is a cost-effective solution. I'm having a few issues with my weewx disconnecting from the internet every few hours and wonder if the 2GB one I have is too small for the job? It certainly runs into space problems when trying to update packages.

Can anyone highlight if it's just Weewx that has the intensive write activity requiring the durable SD card? If that's the case, has anyone shifted the bulk of the file space onto an external USB? I found this article that explains how to do it https://www.raspberrypi.org/documentation/hardware/raspberrypi/bootmodes/msd.md

Thanks in advance for any advice.
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: galfert on February 23, 2021, 01:24:22 PM
The use of external USB with a reliable hard drive does not improve your cost perspective compared to SLC SD cards. Also not all "industrial" SD cards are SLC (Single Level Cell). Which means that you should not go by marketing labeling. Sure some "industrial" SD cards are designed a bit better for use in dashcams and such but they are still not at the level of SLC SD cards. The benefit of the USB enclosure with a USB hard drive is performance and the cost for reliable storage compared to SLC SD.

You ask if WeeWX has intensive write activity? Well the question is not whether WeeWX has intensive writing going on but rather the issue is that any Raspberry Pi by nature of the Linux operating system running and doing what it does alone is reason enough to warrant something better than a regular SD card.

If you've been running a Raspberry Pi for a few years on a regular SD card, then I would start to be concerned and plan for some upgrades.

Regardless a regular data backup strategy is essential on any computer system, even if you have reliable storage.
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: johnd on February 24, 2021, 03:34:25 AM
The benefit of the USB enclosure with a USB hard drive is performance and the cost for reliable storage compared to SLC SD.

The other significant benefit of an external SSD (say but let's include all external hard drives) on a Pi is availability. It's trivially easy to get a suitable SSD and USB adapter from eg Amazon. The same isn't necessarily true at all for SLC SD cards.

And TBH I don't know offhand exactly what backup solutions are built in to the various Pi station software programs, but I really would like to see an option to easily configure automatic backups to the common cloud storage options like Dropbox, OneDrive, Google Drive etc.
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: DaleReid on February 24, 2021, 07:05:18 AM
Greg, et. al. who have done a card replacement:

If you pull a working card from the Pi and do an image of it with a different computer, I assume you can just plug the new card in and continue along with the life of the new card, or so I hope.  I'm approaching a year on my wx system running WeeWx, and if it fails, I literally would have to start from ground zero.  I'd rather spend a couple days fiddling with new stuff than trying to capture the system the way I have it installed and running now.

Did you find, with your reading, any specific SD cards that are more reliable/robust/better choice than the SanDisk that comes with some of the RaspPi kits?

I'm still hoping to keep the almost invisible profile of a self contained Pi. To hang another powered USB box, with it's wall wart and the external drive seems to add to the clutter.  And an external USB drive as shown in some of the linked articles is a mechanical device, drawing power and I'm not sure designed to spin all day, day in and day out.  So in addition to the pile of electronics and the extra power strip wall wart and all, am not sure if it isn't better to just do SD card swaps, not knowing when one will fail, vs. wasting a card with an unknown time to failure when you plug in the next SD card.

A USB stick seems to be relatively small, not require more power from parts dangling and plugged into their own supply and so on.  Is the memory technology in them able to have many more writes than the SD card technology?

I'd spring for a little SSD but those are SATA based and there seems no provision to hang one onto a Pi

Finally, once the new alternative storage has been selected, is there an easy way to migrate things to the new configuration, or is it better to just bite the bullet and do the time-consuming new install on new storage system/Raspbian set up? 

All very concerning as to the amount of work to get this done with the Achilles heel of the SD card life at the root of all this.
Dale
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: mcrossley on February 24, 2021, 09:06:21 AM
I don't have a picture of my Pi 4 with SSD, but here is my old Pi 3B (I keep it as a backup). The SSD is normally stuck to the top of the case with a Velcro pad, it is separate here.

As you can see, no extra power required, and the SSD is smaller than the Pi!


(https://weather.wilmslowastro.com/images/pi3.jpg)
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: johnd on February 24, 2021, 10:28:45 AM
The Pi ecosystem is forging ahead. The Argon M.2 case allows an M.2 (SATA) drive to become part of a neat Pi installation. (No NVMe option, but that would be pointless with communication limited to USB3).

https://www.amazon.com/Argon-Raspberry-Support-B-Key-Compatible/dp/B08MJ3CSW7

Granted, the overall price is starting to creep up, but if you're sending $500+ on the weather station then another $100 or so on the Pi package might not be disproportionate.

Or a cheaper if less pretty option might be the TerraPi stand to use with an SATA SSD in a 2.5" case:

https://theterrapi.com/ and https://theterrapi.com/theterrapi/

They also sell a suitable USB3 to SATA adapter accessory.

Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: DaleReid on February 24, 2021, 12:36:31 PM
Thanks for the ongoing discussion.

Mcrossley, do you know if the Verbatim SSD has a different technology so that it won't loose it's ability to read/write in a year or so, too?  I assume it does since my Samsung SSD runs 24 hours a day in another computer that has been on for years.  Just checking.

John, you are so right that a few bucks more right now to have a trouble free system for the foreseeable future is worth it.  I am getting less and less enthralled with the 'opportunity' to rebuilt a system when a component fails.  My idea of the Pi is to have it tucked out of sight and out of mind, just doing its job.

Dale
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: mcrossley on February 24, 2021, 12:47:48 PM
Mcrossley, do you know if the Verbatim SSD has a different technology so that it won't loose it's ability to read/write in a year or so, too?  I assume it does since my Samsung SSD runs 24 hours a day in another computer that has been on for years.  Just checking.
AFAIK its just SSD (probably an M.2 I haven't split one open to find out) and USB adapter in neat package. I can't see them inventing new technology at the price they sell them.

That one had been sat there continuously running my two web sites, MySQL server, and Cumulus MX 24x7 for three years before I retired it to my backup for live server role - I copy across the database and Cumulus data files to it once a day and it has the software installed ready to go. It's still running fine.

The extra capacity of an SSD (that is small one at 128 GB) over the SD card you would normally use means there are more memory locations for the internal wear levelling to work with anyway.
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: davidmc36 on February 24, 2021, 08:47:27 PM
That Argon case is sick.

I found some files to print cases too. Dedicated compartments for fan, drive, and Pi. Sort of cool
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: gszlag on February 27, 2021, 02:20:36 PM
I decided to back up my SD card( about 18 months old running 24/7) for my rpi 3B+ using the win imager. Just in case.

All seemed fine. It read the card and generated the backup file. Put back the card in the rpi and fired it up.
Dead. Everything gone. No OS, no weewx. No nothing.

Ok. let's use the backup image.

Nope..just a steady red LED.

Well, now I had an excuse to upgrade weewx to 4.x and install the latest Raspberry pi OS.
Reinstall weewx and all extensions, apps, etc, etc.
Tomorrow will get my Bosch barometric sensor going again.
But now..am beat..
PS. a backup of weewx.conf came in real handy.

PS. tried to upgrade to a better SD card - Samsung Endurance (32GB) pro but no go. That card is just slightly smaller than the Samsung EVO Plus that went bad. Will do post mortem later.
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: miraculon on February 27, 2021, 02:55:27 PM
Greg, et. al. who have done a card replacement:

If you pull a working card from the Pi and do an image of it with a different computer, I assume you can just plug the new card in and continue along with the life of the new card, or so I hope.  I'm approaching a year on my wx system running WeeWx, and if it fails, I literally would have to start from ground zero.  I'd rather spend a couple days fiddling with new stuff than trying to capture the system the way I have it installed and running now.

Did you find, with your reading, any specific SD cards that are more reliable/robust/better choice than the SanDisk that comes with some of the RaspPi kits?

I'm still hoping to keep the almost invisible profile of a self contained Pi. To hang another powered USB box, with it's wall wart and the external drive seems to add to the clutter.  And an external USB drive as shown in some of the linked articles is a mechanical device, drawing power and I'm not sure designed to spin all day, day in and day out.  So in addition to the pile of electronics and the extra power strip wall wart and all, am not sure if it isn't better to just do SD card swaps, not knowing when one will fail, vs. wasting a card with an unknown time to failure when you plug in the next SD card.

A USB stick seems to be relatively small, not require more power from parts dangling and plugged into their own supply and so on.  Is the memory technology in them able to have many more writes than the SD card technology?

I'd spring for a little SSD but those are SATA based and there seems no provision to hang one onto a Pi

Finally, once the new alternative storage has been selected, is there an easy way to migrate things to the new configuration, or is it better to just bite the bullet and do the time-consuming new install on new storage system/Raspbian set up? 

All very concerning as to the amount of work to get this done with the Achilles heel of the SD card life at the root of all this.
Dale

Dale,

Sorry for the delayed response, I have been out of town all this past week.

I used this SD card (https://www.mouser.com/datasheet/2/669/product_brief_western_digital_industrial_ix_qd334_-1949240.pdf) in my meteohub and so far, so good.

It is a SLC architecture card. I haven't tried a generic RaspPi distribution with a simple clone, but I know that Boris' meteo* architecture doesn't allow cloning for obvious reasons, so I backed up my settings are did a fresh install of the meteohub image. (I know, I know, I should go to meteobridge, etc. but I like my custom plots and scripts)

Greg H.
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: WA4OPQ on March 27, 2021, 12:35:43 PM
Speaking of SD cards.....

I have three layers of SD card "quality" in use

I have converted one of my meteobridge installs to a pi, which requires a SLC card
I found 2GB SLC on eBay for $5 each.

I have several remote stations, each about 30 minutes from my home.
On those I use Sandisk Industrial cards. Not SLC but a grade above consumer products, and just a few dollars more.
https://www.amazon.com/gp/product/B085GLQB78 (https://www.amazon.com/gp/product/B085GLQB78)

Then for any pi I use at my home I use Sandisk Ultra
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: johnd on March 27, 2021, 12:38:06 PM
I found 2GB SLC on eBay for $5 each.

And you believe that?!?!
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: WA4OPQ on March 27, 2021, 01:47:23 PM
I found 2GB SLC on eBay for $5 each.
And you believe that?!?!

Yes, they're arrived and check out good.
https://www.ebay.com/itm/2GB-Micro-SD-cards-Lot-of-5-Industrial-Grade-AF2GUDI-MOT1-1P-ATP/184512207900 (https://www.ebay.com/itm/2GB-Micro-SD-cards-Lot-of-5-Industrial-Grade-AF2GUDI-MOT1-1P-ATP/184512207900)
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: egeezer on April 03, 2021, 04:22:53 PM
You might even want to try using an SSD, which would do well in applications requiring lots of R/W activity.

Here's an article on 'how to' and performance from Toms Hardware;
 https://www.tomshardware.com/news/raspberry-pi-4-ssd-test,39811.html
It also links to an article on how to enable boot from SSD. I'd suggest reading it fully before selecting a drive.

SSDs have come down in price since the article was posted. I looked briefly and found external drives at Micro Center for as little as $40. A SATA SSD drive with a USB case might also be an option. Just be sure to verify compatibility. 
 See https://www.microcenter.com/search/search_results.aspx?N=4294822457+4294966998&NTT=External+SSD&NTK=all&sortby=pricelow
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: Nekota on April 04, 2021, 03:04:37 PM
I have had a dozen or more RPi's and a fair number of SD card corruptions.  What I found is the card is not worn out but corrupted probably due to power glitch or dropout.  The solutions I have found are to use the low level diskpart on windows pc to recover the SD card and a battery backup power supply for the RPi.  Note that diskpart can erase any of your drives so be very careful to select the SD flash card. (For details Google diskpart usb flash recovery).  For the backup power source I use a 2.5A DC power supply and the Adafruit PowerBoost 1000 charger.  I have one RPi recording temperatures from a heat pump for the past 7 years with a 16G SD card.  It has been corrupted several times but since putting the powerboost backup on the RPi I have not had any more corruptions.  I also have powerboost on two other RPi computers (one is for power level monitoring recording two readings every 6 seconds and a PiAware for Flight Aware monitoring SDR radio) and both have had no SD card problems since I started using the powerboost 1000 backups.  Rather than spend money for SLC I put the $ on getting a larger SD flash card (currently 64G is my preference) and let the SD card space through wear leveling provide the longer life and use battery backup for the RPi.   
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: davidmc36 on April 04, 2021, 03:12:38 PM
How is wear leveling taken care of?
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: Nekota on April 04, 2021, 09:21:22 PM
How is wear leveling taken care of?

Flash memory devices have an embedded controller which performs the mapping of logical blocks of data to the physical blocks on the chip. This is transparent to the operating system and the controller keeps counts of how many times each physical block has been written to. When data is added or changed requiring a write to the flash memory the controller updates the data and writes to a new location having fewer writes and erases the old location. The old location is now available for a new write and the leveling table is updated to account for the write/erase cycles.  There are several algorithms to implement wear leveling with performance and reliability tradeoffs. Search for dynamic vs static wear leveling for more details. An example link is https://www.atpinc.com/blog/how-SSD-wear-leveling-works  (https://www.atpinc.com/blog/how-SSD-wear-leveling-works)
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: WexfordWx on April 05, 2021, 10:43:39 AM
I found this thread to late in the day to save my hair from been torn out bunch by bunch. I have run a meteohub controlled station for about 10 years. Until it packed up I used a Sheeva plug computer; in this one, the SD cards lasted an average of 2-3 years. I had to clear the memory several times with a Linux computer as the memory filled up with tables. I kept an RPi as a backup and when the Meteohub died I started using the RPi3. After about 6 weeks it stopped calculating averages then after 6 or 7 months it stopped working altogether. So I got new SD cards and configured them. Three times I had this experience. Boris was little help, he said I must be using cheap SD cards, which I was not.

I gave up. I bought two WiFi Loggers for my two Davis consoles and now I can rest easy knowing I will not have to contend with formatting and configuring Meteohub SD cards ever again.

I have two Meteohub licenses and two Davis Weatherlinks available for charity or educational purposes if someone wishes to contact me. I will repeat the offer under a new Subject.
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: DaleReid on April 05, 2021, 02:01:49 PM
How are the memory areas on the meteohub or dataloggers different than the SD cards?

Do the SDs write often and even if there is no activity to log, whereas the dataloggers/hubs only write when a new data point comes in, every few minutes rather than millions of times per second?
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: WexfordWx on April 05, 2021, 05:44:07 PM
Dataloggers such as WiFiLogger do not generally use SD cards/flash memory for live data, only for holding the software and parameters needed for its operation. They use R/W memory (RAM) for holding the met data, this is transient but this does not matter as data is only computed and stored for a few minutes, i.e. until the next transmission. R/W memory can be used, erased and reused endlessly without deteriorating.
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: galfert on April 05, 2021, 06:06:47 PM
Boris was little help, he said I must be using cheap SD cards, which I was not.
If you were not using SLC type SD cards then you were using cheap SD cards. You say you weren't using cheap cards but you are not specifying what you were using. Even if it says industrial or long life or even if they say that they are designed for dashcams...not good enough unless it is SLC. Boris may have said you were using cheap SD cards but what he really meant by cheap is non-SLC type. The latest Meteobridge has a requirement of using SLC type cards and there is a link to acceptable SLC type cards.

Here is that list of SLC supported card. Yes this is for the Meteobrige but this is still a good list to go by to know that you are using SLC.
https://www.meteobridge.com/wiki/index.php/Hardware#Raspberry_Pi_Model_3B.2C_3B.2B.2C_4B

Quote
I gave up. I bought two WiFi Loggers for my two Davis consoles and now I can rest easy knowing I will not have to contend with formatting and configuring Meteohub SD cards ever again.
WiFiLogger has no archive storage....it only uploads data to other places.  You aren't comparing apples to apples in terms of capabilities. I'm sure WiFiLogger is great for many users, just know that different devices have different uses. Boris recommends those using Meteohub to upgrade to Meteobridge. He even ran a special upgrade pricing a few months back.
 
Title: Re: SD card flash life on Wx programs using Raspberry Pi
Post by: WexfordWx on April 05, 2021, 06:46:18 PM
I stand corrected! Boris did recommend using a swissbit card in my RPi Meteohub alright and I spent hours trying to find an affordable 16GB microSD. Unfortunately the Meteohub advice is to use a much larger card than is apparently needed in the Meteobridge. I could not find one for under €100 and even then I would have to have waited 6 weeks for delivery. I was not aware of the importance of using SLC type, I just looked for industrial grade. Perhaps I was using fakes, I even downloaded software to try and avoid these.

Your point regarding the WiFiLogger is well made. Horses for courses! Regarding the Meteohub versus the WiFiLogger, the latter is suitable for my purposes as I do not use or need the tables generated by the Meteohub, I take raw data and calculate my own.