Trixology

Weather => Weather Hardware/Measurement => Topic started by: elagache on October 09, 2015, 09:35:26 PM

Title: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: elagache on October 09, 2015, 09:35:26 PM
Dear WeatherCat weather station “mods” fans,

We live in a world filled with thermometers.  Alas, anyone who has put some effort into measuring the temperature accurately knows this is extremely hard to do.  Top of the line stations like the Davis FARS line improve the measurement of the air temperature by actually blowing air over the temperature probe with a fan.  Doing this in a self-contained solar powered unit is something of a feat and Davis makes you pay for this luxury.  Worse still, the Davis unit will wear out eventually so that owners can expect to buy new batteries and/or motors down the line.  Those of us without this luxury are out in the cold (or heat.)  That is until we take the matter into our own hands and attempt to modify our station to improve the performance of our instruments.

Some of the guys on the WX-Forum have been using PC case fans to aspirate their temperature/humidity sensors.  This write up is how I incorporated a 3” PC case fan into my Davis temperature/humidity probe.  While this is a very specific application, these ideas can be used to modify a wide range of makes and models of weather stations.  It is a scheme well worth considering to improve the temperature accuracy of your weather station.

The story starts back in February of 2014.  As part of moving my station transmitter board from my rain gauge to the temperature/humidity sensor under our large deck, I purchased the Davis daytime only fan aspiration kit:

http://www.davisnet.com/weather/products/weather_product.asp?pnum=07747 (http://www.davisnet.com/weather/products/weather_product.asp?pnum=07747)

Since there is no practical way to mount a solar panel under the deck, I planned to power my station transmitter board with AC power.  With that power available, I could easily power the Davis fan using a universal AC adapter.  Alas, as reported on WX-Forum, these fans do not last very long when powered at 3 volts.  Within a few months, the fan motor had died.

Since I was aware of this, I had already planned to replace the motor.  From other sources on the Internet, I was aware that it was no longer possible to get a quality replacement for the motors that Davis uses.  So another arrangement was needed, and I had already decided to substitute a 3” PC case fan.  My thinking was that having the Davis adapters would make the task easier.  As it turns out, while it did make the job easier, there were other ways to incorporate the fan that would avoid this significant expense.

Back in February, I had done some research and purchased this particular fan model - the Noctua NF-A8 PWM:

http://www.noctua.at/main.php?show=productview&products_id=100&lng=en (http://www.noctua.at/main.php?show=productview&products_id=100&lng=en)

It was more expensive, but I hoped that would make more durable in the more difficult semi-outdoor environment.  I had also bought a multi-voltage AC to DC adapter:

http://www.vellemanusa.com/products/view/?country=us&lang=enu&id=350744 (http://www.vellemanusa.com/products/view/?country=us&lang=enu&id=350744)

These devices are produced by many vendors and can be bought just about anywhere.

By in February, I had connected the Davis fan to the AC adapter using a 1/8” inline connector from Radio Shack:

(https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-BcgqFsg/0/L/8%22%20inline%20power%20connector%20for%20fan%20-L.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-BcgqFsg/A)

This is how my station remained until the original Davis fan failed.  Fast forward to this October and I really wanted to restore fan aspiration before the bad weather returned.  It was time to take on the case fan “mod.”

I took my temperature/humidity housing back apart and retrieved the portion that contained the Davis motor.  This is what I was greeted with:

(https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-37wz32g/0/L/Old%20fan%20and%20housing-L.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-37wz32g/A)

Clearly Davis simply packages the daytime only fan aspiration system in the same components that house the batteries for the 24/7 system.  I was quite surprised at how difficult it was to attempt to extract the original motor.  Replacing the original components would not be easy even if quality replacements existed.

Here is the PC case fan in the same space:

(https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-W5LbqPs/0/L/3%22%20PC%20case%20fan%20in%20opening%20-L.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-W5LbqPs/A)

It seemed to me the easiest way to make this modification was to remove all the plastic of the lip that supported the original Davis fan assembly and secure my PC case fan using a metal plate.

So first I removed the lip.  This turned out to be a bit tedious.  I sawed off as much as I could.  I then used a Dremel rotary tool to get close to base.  Finally I carved the remaining material with a hobby knife.  That left me with this:

(https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-rBHQp6q/0/L/Top%20of%20Davis%20cone%20removed%20-L.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-rBHQp6q/A)

At this point I put to work my “secret weapon.”  I’ve gotten skilled at creating templates using my favorite illustration software Canvas (http://www.canvasx.com/en/products/canvas-draw).  In this case, it was fairly easy to make a template based on taking the dimensions of the various components.  If the template is more difficult to make, there is a strategy using your camera that will help.  Take a photograph of the region where the template will fit and include a ruler to provide a scale.  You can then scale the photograph to actual size and then either use a computer or even draw by hand the template needed.  If you want to make exactly the same modification as I have done, the template I used is available as a PDF file:

http://www.canebas.org/WeatherCat/Forum_support_documents/PC%20case%20fan%20bracket.pdf (http://www.canebas.org/WeatherCat/Forum_support_documents/PC%20case%20fan%20bracket.pdf)

A 1 inch scale is included so that you can confirm it has printed correctly.

One huge advantage of making templates like this is that you can make prototypes to confirm the fit.  I routinely print out a template and glue it to posterboard using rubber cement:

(https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-VQZRVgQ/0/L/Plan%20glued%20to%20poster%20board%20-L.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-VQZRVgQ/A)

In this case I was quite lucky the template fit with very little modification:

(https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-jP6tttr/0/L/Prototype%20plate%20fitted%20to%20shield%20-L.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-jP6tttr/A)

At this point I could now repeat the process using metal.  I decided to use some 0.032” anodized aluminum sheet that I had successfully used on some projects for my trusty wagon.  I glue the paper template to the metal with rubber cement - this works just fine for the brief period the paper needs to be there:

(https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-TrMDZTd/0/L/Template%20glued%20to%20Aluminum%20-L.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-TrMDZTd/A)

To cut the aluminum, I used aviator tin snips.  They have a mechanical advantage so that it is closer to using scissors than cutting metal.  First I cut out a broad region containing the template and then drilled the holes for mounting the case fan:

(https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-2JF294z/0/L/Drilling%20mounting%20holes%20-L.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-2JF294z/A)

As you can see my holes departed from my original template.  I was concerned that my template could have been a bit off on the holes and so I used the fan directly.  Alas, the fan pivoted while I was attempting to get the hole positions.  This could come back to haunt me.

To cut the hole for the air to blow through I did the old fashioned trick of drilling a few holes in a line so that I could start cutting.  I then followed a spiral pattern until I reached the desired diameter:

(https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-md3b6hL/0/L/Fan%20opening%20exposed%20-L.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-md3b6hL/A)

Finally, I cut the outer shape of the template.  The best way to get accuracy is to be willing to cut out small chunks rather than trying to cut shapes in one step.  With a little filing I had a reasonably good fit:

(https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-3t6b6px/0/L/Aluminum%20plate%20in%20position%20-L.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-3t6b6px/A)

I then glued the aluminum plate to the Davis part using 2-part epoxy:

(https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-cdDnRK8/0/L/Gluing%20plate%20with%20epoxy%20-L.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-cdDnRK8/A)

I used the fan itself to transfer weight to the plate and insure a good contact between the plastic and the aluminum.

Another task that was required was to solder the case fan wires to the power source.  This can be confusing because modern case fans have 4 wires so that they can be controlled by the computer.  It turns out that the black wire corresponds to ground and the yellow wire should be at +12 Volts DC.  For now I just soldered the wires directly:

(https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-pXB4f7B/0/L/Soldering%20fan%20leads%20to%20connector%20-L.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-pXB4f7B/A)

I then just applied old-fashioned electrical tape:

(https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-B9Snz57/0/L/Solder%20connection%20covered%20with%20electrical%20tape%20-L.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-B9Snz57/A)

If these fans can last 5 years or more, that might be good enough.  It isn’t that difficult to redo the connection if it is that infrequent a replacement.  If the fans last only a year, then some sort of connector would be the way to go.

At last it was time to assemble everything.  Here is how the gluing job turned out:

(https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-VxnW7jm/0/L/Case%20fan%20mounting%20plate%20glued%20to%20Davis%20piece%20-L.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-VxnW7jm/A)

Mounting the fan on the plate was more of a chore than I wished because of the slip of the mounting holes.  I had to file some of the screws because their was so little clearance in the Davis part.  However, after those adjustments were made, the fan was secured and wires connected:

(https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-G6MD53P/0/L/PC%20case%20fan%20installed%20on%20plate%20-L.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-G6MD53P/A)

After that, I secured the temperature/humidity assembly underneath the fan assembly:

(https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-4Z7CRsm/0/L/Fan%20component%20attached%20to%20radiation%20shield.-L.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-4Z7CRsm/A)

Finally, the entire assembly was mounted next to the station transmitter board.  Here is the view with the board visible:

(https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-mN5tmLs/0/L/Temperature%20assembly%20installed%20-%20ISS%20open%20-L.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-mN5tmLs/A)

Here is what the area under the deck looks like with the transmitter housing closed:

(https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-Srr696D/0/L/Station%20in%20normal%20operation.%20-L.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-Srr696D/A)

Overall this has been a real improvement over the original Davis fan.  This fan is much quieter and the temperature/humidity probe seems much more responsive to changes in temperature.

This project may seem limited to a very unique application, but there is no reason to limit yourself to AC to DC adaptors and without that limitation then many more options become possible.  For example, you could buy the following 12 Volt 5 Watt solar array and use that to power your PC case fan:

http://www.amazon.com/gp/product/B00QRHDIPY/ref=pd_lpo_sbs_dp_ss_1?pf_rd_p=1944687642&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B006Q7C7L6&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=1E6BFRD4Y8H6K0M3KF1T (http://www.amazon.com/gp/product/B00QRHDIPY/ref=pd_lpo_sbs_dp_ss_1?pf_rd_p=1944687642&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B006Q7C7L6&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=1E6BFRD4Y8H6K0M3KF1T)

That would provide daytime aspiration at a modest cost and it is during the daytime that a fan is most beneficial.  With a little more digging around, there might a 12 volt solar system out there with a rechargeable battery at a moderate cost.  That would make it possible to create a 24/7 case fan station aspiration system for any make and model of weather station and at any location with sun exposure.

In retrospect, I wasn’t as bold as I could have been.  It would have actually been easier to create a circular aluminum panel that could have been sandwiched between the plates of the radiation shield and supported by spacers and longer mounting screws.  That approach could be tried for any weather station where it is possible to dismantle the radiation shield.  The solar panel need not be located nearby the temperature sensor, so there is a lot of flexibility in creating a fan aspirated temperature system for any weather station.

So I hope this write up has given a number of WeatherCat station caregivers some fresh inspiration on what they can do with their station.  It isn’t only classic cars that can get ”mods!”

Cheers, Edouard

Title: Re: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: wurzelmac on October 09, 2015, 10:20:45 PM
Cool description, you will make it to ifixit.com!

Two weeks too late for me, I replaced the Davis fan with ... a new Davis fan.  :-[

Cheers,
Reinhard
Title: Re: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: SeanA on October 09, 2015, 10:24:05 PM
As solutions go that is top... [tup]
Title: Re: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: Blicj11 on October 10, 2015, 07:16:37 AM
Fascinating and thorough description accompanied with easy to understand photos! Nice job MacGyver.
Title: Re: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: WCDev on October 10, 2015, 02:06:34 PM
Impressive work!
Title: Re: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: xairbusdriver on October 10, 2015, 04:35:43 PM
Nice!! [cheer] [rockon]

Now all you need to do is build 50 of these 'kits' and offer them to some dealer. I think this is how Mr. Jobs got started! And you already have a garage! Of course, you may have to sell your beloved 'transportation'! I'll bet it will provide more capital than did his VW van! ;)
Title: Thanks! (Re: PC case fan to aspirate your temperature/humidity probe.)
Post by: elagache on October 10, 2015, 09:30:33 PM
Dear Reinhard, Sean, Blick, Stu, X-Air, and WeatherCat tinkerers, . . 

Thanks for the praise!  :)  I've gotten into the habit of documenting the work I do on my wagon in this way.  So far I haven't done any harm to my fancy Canon camera by lugging it into the workshop while building things.  If I have pictures like this it helps me put things back together while otherwise I might have forgotten how!

Two weeks too late for me, I replaced the Davis fan with ... a new Davis fan.  :-[

Perhaps two weeks too late for this Davis fan, but perhaps an advanced warning when the time comes to replace the next fan.  Apparently, you cannot buy good quality 3 volt motors anywhere.  If Davis could find them, I think they would buy them.  That's what their customers are expecting.

Now all you need to do is build 50 of these 'kits' and offer them to some dealer.

Actually I really doubt many other setups will be made exactly like I did it.  It is very unusual to have AC power nearly your station transmitter.  This may encourage a few others to consider powering their Davis station using AC.  It does have some advantages.  Beyond that this project is in a way unfinished.  The next step is for somebody to see if they can find a solar power unit that will allow them to power a PC case fan "off the grid."  I hope someone is inspired enough to do that someday.

And you already have a garage! Of course, you may have to sell your beloved 'transportation'!

Perish the thought!!!

After all the effort I've put into my trusty wagon, I'm really looking forward to driving her once more.  I haven't really been able to do that in over 5 years!

Cheers, Edouard  [cheers1]
Title: Re: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: Bull Winkus on October 12, 2015, 02:39:35 AM
(http://i.ytimg.com/vi/GVDU4ywnOHY/hqdefault.jpg)

Wonderful job there, Mr. Wizard! And the write up was first rate, too!

Thanks for sharing.
Title: Thanks! (Re: Using a PC case fan to aspirate your temperature/humidity probe.)
Post by: elagache on October 12, 2015, 09:00:30 PM
Dear Herb and WeatherCat station "mods" fans,

Wonderful job there, Mr. Wizard! And the write up was first rate, too!

Thanks Herb!  :)

When we finally get a rainy day (I hope, I hope!!! . . (http://www.canebas.org/WeatherCat/Forum_support_documents/Custom_emoticons/pray.gif) . . )  I'll try to do the write up of Canebas Weather Station 2.0 in which I move the station transmitter board from next to the rain gauge to under the other deck where there is AC power.  The only other potential use of this "mod" is if you decide to power your station with AC.  It isn't as hard to do as it looks - provided of course you have a handy source of AC power outside.

Cheers, Edouard
Title: Going strong after 6 weeks. (Re: Using a PC fan to aspirate your temp probe.)
Post by: elagache on November 26, 2015, 10:31:07 PM
Dear WeatherCat station "mods" fans, . . . .

I had some work to do immediately underneath my temperature/humidity probe this afternoon and I could clearly hear the smooth and steady "hum" of the PC case fan I installed.  It has only been 6 weeks, but we have already had some blustery conditions which could have been stressful on a fan not designed for the outdoors.  So far, so good!  [tup]

Cheers, Edouard
Title: Re: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: LesCimes on November 28, 2015, 10:13:50 PM
I commented a while back that my fan fan was no longer working. (Don't recall which thread it was.) Well, I went out the other day and was checking up on the ISS - discovered that the fan was operating! Boy was I surprised. Now I'm wondering why it wasn't working previously. Perhaps it needs a lot of sunlight to power it and the solar panel is wearing down. I don't know. Oh well, glad to have it back operational.
Title: Checking Davis motor (Was: Using a PC fan to aspirate your temp probe.)
Post by: elagache on November 28, 2015, 10:58:21 PM
Dear Michael and WeatherCat station caregivers,

I commented a while back that my fan fan was no longer working. (Don't recall which thread it was.) Well, I went out the other day and was checking up on the ISS - discovered that the fan was operating! Boy was I surprised. Now I'm wondering why it wasn't working previously. Perhaps it needs a lot of sunlight to power it and the solar panel is wearing down. I don't know. Oh well, glad to have it back operational.

Certainly, it is best when the station works without any maintenance!  When I was troubleshooting my own station, I was told by Davis tech support that they had never seen a solar panel fail.  I suppose the output decreases some as the the plastic cover gets discolored, but that shouldn't have much of an effect on the fan.

If it isn't too hard to reach, you might want to take it apart someday and just make sure everything is in good order.  You could measure the voltage going to the fan from the lower solar panel to see if it is about the same as the voltage powering the station.  That would allow you identify any solar panel issues.  Something else that seems worth checking is simply making sure everything is clean around the motor.  When I did this "mod" I was surprised at how much debris had managed to get in between the shells of the radiation shield.  Since the Davis motor isn't getting a lot of power, it might have more difficulty moving the air if the intake is partially obstructed.

Cheers, Edouard
Title: Re: Checking Davis motor (Was: Using a PC fan to aspirate your temp probe.)
Post by: Blicj11 on November 28, 2015, 11:35:08 PM
When I was troubleshooting my own station, I was told by Davis tech support that they had never seen a solar panel fail.  I suppose the output decreases some as the the plastic cover gets discolored, but that shouldn't have much of an effect on the fan.

Davis told me the same thing. Your panel is fine unless the plastic cover discolours.
Title: Re: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: xairbusdriver on November 29, 2015, 01:02:44 AM
Quote
discolours
AHA! Thee hath stated thine problem!
Title: Re: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: LesCimes on November 29, 2015, 07:46:24 PM
Discoloration of the plastic cover could very well have reduced solar penetration. Hmm, might be a "do it yourself" repair job - putting on a piece of glass to replace the plastic.
Title: Still goin' ! (Re:PC case fan to aspirate your temperature/humidity probe.)
Post by: elagache on January 03, 2016, 03:38:22 AM
Dear WeatherCat weather station caregivers, . . . .

This afternoon I had to reload my gopher "weepon" with fresh poisoned bait.  A gopher seems to have strayed into our yard from our neighbor to the east and I need to send it to "gopher heaven" (or whatever is equivalent. . . . )

I happened to be doing this under the the station's temperature/humidity probe and I could clearly hear the hum of the PC case fan I installed in early October.  So it is still running well after close to 3 months.  That still isn't a complete endurance test, but the original Davis fan was sounding very sick after less than a month.  So this PC case fan is doing well considering it is winter and a few storms have already blown threw.

We'll see how long this fan can last!

Cheers, Edouard  [cheers1]

P.S. Anyone who thinks that the mild California weather is delightful clearly didn't have to fight gophers in January! . . .  >:(
Title: Re: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: xairbusdriver on January 03, 2016, 02:34:40 PM
Maybe it's that "mild California weather" that is helping support Gophers! Even Minnesota has interweb service especially at the University. Are these "Golden (http://www.gophersports.com)" by any chance? ;D
Title: Hoping gopher is dead - fan isn't! (Was: Using a PC case fan)
Post by: elagache on January 03, 2016, 10:32:15 PM
Dear X-Air and WeatherCat collegiate sports fans, 

Maybe it's that "mild California weather" that is helping support Gophers!

I'm afraid you are correct on that one.  Although the gophers do well in winter and then really pay the price in the summer-time when the soil dries out into something close to concrete.  I usually only have gopher problems in the spring, but this year it is starting early.

Even Minnesota has interweb service especially at the University. Are these "Golden (http://www.gophersports.com)" by any chance? ;D

Since I poison the darn critters without exposing their tunnels, I never do find out what color they are.  However, honestly I couldn't care less what they look like other than dead!   As a precaution I applied another round of poisoned bait this afternoon and once more was able to check up on the fan.  I'm very pleased.  It is so quiet that you can hardly hear it, but it continues to work very well!  :)

Cheers, Edouard  [cheers1]
Title: Re: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: xairbusdriver on January 04, 2016, 04:58:49 PM
Quote
It is so quiet that you can hardly hear it
I find that leaving out the batteries for my hearing aids adds that effect at a much lower cost! :)

I assume that you have actually observed that animals causing your problems. If not, it might be wise to determine if they are Gophers, Moles, Voles, Shrews, etc. Different species respond different treatments, these animals all have different EULAs! Be sure to contact their individual legal representatives, often called "Rodent Attorney Trade Support" (RATS).
Title: Re: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: Steve on January 04, 2016, 11:06:46 PM
Santa left me a replacement fan from Rainman Weather. If this one bites the dust, I think I'll follow your lead.
Title: Time will tell! (Re: PC case fan to aspirate your temperature probe.)
Post by: elagache on January 05, 2016, 11:34:38 PM
Dear Steve and WeatherCat station caregivers, . . .

Santa left me a replacement fan from Rainman Weather. If this one bites the dust, I think I'll follow your lead.

Well if that fans also dies you'll have two pieces of information:


If and when that time comes, you'll know better what to do!

Cheers, Edouard  [cheers1]
Title: A-Okay after a year! (Re: PC case fan to aspirate your temperature probe.)
Post by: elagache on October 06, 2016, 11:42:48 PM
Dear WeatherCat station caregivers,

My station went live October 1st, 2009.  So I try to give the station an annual check about the start of October.  Last year you may remember I upgraded my station with a PC case fan to aspirate my temperature/humidity probe.  Today was the day I finally managed to take the radiation shield apart and see how the fan was coping with the outdoors.  And the answer is:

(https://photos.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-wvjFC3B/0/XL/PC%20case%20fan%20on%20radiation%20shield%20after%201%20year%20of%20operation%20-XL.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-wvjFC3B/A)

The fan isn't even as dusty as I've seen some fans on computers inside the house!  Here is a photo of the temperature/humidity probe:

(https://photos.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-wvjFC3B/0/XL/PC%20case%20fan%20on%20radiation%20shield%20after%201%20year%20of%20operation%20-XL.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-wvjFC3B/A)

The parts hardly look new, but the dust isn't even close to restricting the air flow.  I removed the loose material with an air duster and reassembled everything.  When I plugged the fan back it I could hear it's very quiet whisper.

So at least one year into this experiment, it appears that PC case fans are indeed perfectly practical replacements to aspirate your temperature/humidity probe.

Cheers, Edouard  [cheers1]
Title: Re: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: Blicj11 on October 08, 2016, 07:18:25 AM
I love it when a plan comes together.
John "Hannibal" Smith
The A-Team
Title: Fan dead after 2 years (Re: PC case fan to aspirate your temperature probe.)
Post by: elagache on October 02, 2017, 12:09:09 AM
Dear WeatherCat station caregivers,

2 days ago I realized that I wasn't hearing the usual "hum" from the PC case fan I installed 2 years ago.  Yesterday I power-cycled the fan hoping that would kick it back to life - no dice.  Finally today I made a more careful inspection.  First I double-checked that the power supply was still working.  Then I opened up the temperature/humidity radiation shield to look at the fan itself.  It didn't look too bad really:

(https://photos.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-cr9TpgM/0/ccac9acf/XL/Condition%20of%20first%20case%20fan%20that%20failed-XL.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-cr9TpgM/A)

I've seen dusty fans inside computers that were still working fine.  So losing this fan after 2 years wasn't a satisfactory life-span in my opinion.  I started a thread on the WXForum to get some advice on this sort of thing:

http://www.wxforum.net/index.php?topic=32961.0 (http://www.wxforum.net/index.php?topic=32961.0)

There I was informed about fans with an IP68 rating.  These fans are rated to cope with dust and moisture.  It is definitely a better choice for an outdoor environment.  I got a recommendation for the Sanyo Denki  9WL0812P4G001 fan.  Here are its specifications:

http://www.mouser.com/ds/2/471/San_Ace_80WL25_E-541667.pdf (http://www.mouser.com/ds/2/471/San_Ace_80WL25_E-541667.pdf)

This fan is rated to last 20 years!  However, it costs almost $100.  That seemed a lot of money for this sort of an application.  However a little more web search and I located a close cousin to this fan from the same manufacturer:

http://www.mouser.com/ds/2/471/San_Ace_80WP25_E-534043.pdf (http://www.mouser.com/ds/2/471/San_Ace_80WP25_E-534043.pdf)

The fan has very similar specifications but it is expected life-span was only 4-1/2 to just under 7 years depending on conditions.  Still that's more than double what my first fan was able to do and hopefully it will be closer to 7 years in the mild California conditions.  I was able to buy this fan on eBay:

http://www.ebay.com/itm/172120113322 (http://www.ebay.com/itm/172120113322)

I wasn't willing to wait a month to replace this fan, so I paid for the economy FedEx international shipping.  That was more than the fan, but hopefully I'll be able to get my station back to full operation sometime mid-month instead of waiting all the way to November.

So stay tuned!  (http://www.canebas.org/WeatherCat/Forum_support_documents/Custom_emoticons/tune_in_TV_emoticon.gif)

In the meantime, if anybody considers making this sort of upgrade definitely consider using an IP68 rated fan.  It probably will save you some premature maintenance!  [banghead]

Cheers, Edouard  [cheers1]
Title: Re: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: Blicj11 on October 03, 2017, 12:47:19 AM
More pictures please, of the new fan, and whether or not you have to make a new metal template, etc.
Title: Same fan footprint. (Re: PC case fan to aspirate your temperature probe.)
Post by: elagache on October 03, 2017, 11:05:22 PM
Dear Blick and WeatherCat DYI types,

More pictures please, of the new fan, and whether or not you have to make a new metal template, etc.

The new fan is also a 3" (80mm) case fan, so it should bolt right back into the position of the old fan without any additional modification.  The one problem was concerned about was whether I should give myself a simpler connector to simplify replacing these fans if they were going die comparatively frequently.  I'm going to hope this new fan can deliver the advertised life.  So once more I'll soldier it directly to my power leads.

Nonetheless, I'll have my camera handy to describe how the procedure unfolds.  I avoided disconnecting the temperature/humidity probe when removing the dead fan, but I'll have to take apart the radiation shield to give it a thorough cleaning.  So the station will be down for a while.

Cheers, Edouard
Title: Fan installed - film at 11! (Re: PC fan to aspirate your temperature probe.)
Post by: elagache on October 23, 2017, 12:16:36 AM
Dear WeatherCat FYI types,

Well it was a terrific struggle, but the new PC case fan is finally installed in my temperature/humidity enclosure.  However, it took all the time I had to get it installed.  So while I took pictures, if you are old enough to remember this: "breaking news at 6pm, film at 11!"  Hopefully sometime tomorrow I'll have the time to download all the images and share with you all the gory details. . . . . .

Cheers, Edouard
Title: Re: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: Blicj11 on October 23, 2017, 05:23:08 AM
Sounds good.
Title: Da' repair! (Re: Using fan to aspirate your temperature/humidity probe.)
Post by: elagache on October 23, 2017, 10:28:11 PM
Dear WeatherCat station hardware FYI types,

As promised, here is da' blow by blow of how I replaced the PC case fan in my modified temperature/humidity enclosure described earlier in this thread.  As reported earlier, I purchased this fan on eBay:

https://www.ebay.com/itm/172120113322 (https://www.ebay.com/itm/172120113322)

Sadly I must report that the vendor changed shipping companies with my order and it took another 4 days over what they promised.  Nonetheless the product was indeed a 3" (80 mm) fan that would mount on the same plate that I had "fabbed" when installing the first fan. 

The first challenge was to figure out how to power the fan.  The previous fan could be powered by providing +12 volts to the yellow wire and connecting the ground to the black wire coming from the fan.  The new fan stubbornly didn't work this way.  By accident I discovered something shocking!  Connecting the +12 volts to the red wire and the ground to black worked perfectly!  Of course that is how it should have been all along - which is why of course I didn't expect it!

Once the matter of actually getting the fan spinning had been solved, it was time to connect the wiring.  My understanding is that crimping is preferable to soldering in exposed outdoor environments, but I don't have crimping tools for wires this small.  So I removed the solder from the connector and then soldered the new fan leads to the old connector wires:

(https://photos.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-WR4Ng7x/0/eb0389f9/XL/Soldering%20fan%20leads%20to%20old%20Davis%20connector-XL.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-WR4Ng7x/A)

The previous fan leads had been protected with electrical tape.  That tape had started to pull away from the wires, so that didn't seem like the best solution.  Since I have purchased a heat gun and heat-shrink tubing, I went that route.  Here is the two leads protected in heat-shrink tubing:

(https://photos.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-9T2Q4D6/0/586408fb/XL/Protecting%20each%20connection%20with%20heat-shrink%20tubing-XL.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-9T2Q4D6/A)

As you can see, this is a much tighter and resistant seal.  For extra protection, I shrunk a second piece of tubing over the entire wire assembly:

(https://photos.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-5gLcxwx/0/e8bf727c/XL/Completed%20wiring%20to%20new%20fan-XL.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-5gLcxwx/A)

Now all that remained was to clean the radiation shield and install the fan.  For reasons I don't understand, the enclosure was more dirty than in previous years.  Here is the photo of the old fan and mounting assembly at 1 year:

(https://photos.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-wvjFC3B/0/78c913cf/XL/PC%20case%20fan%20on%20radiation%20shield%20after%201%20year%20of%20operation%20-XL.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-wvjFC3B/A)

Here is that same mounting assembly before cleaning:

(https://photos.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-5KjM77K/0/37461302/XL/Dirty%20state%20of%20radiation%20shield%20parts-XL.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-5KjM77K/A)

Every component needed some cleaning and while Simple Green degreaser did a good job of releasing the dust and grime, I'm still puzzled about what caused so much more debris to end up in the radiation shield this past year.

Once everything was cleaned up, I could install the fan using the same fasteners that held the previous fan:

(https://photos.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-CvFf4Hx/0/149447c8/XL/New%20fan%20installed%20into%20old%20support%20plate-XL.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-CvFf4Hx/A)

Unfortunately, as you can see it was late in the day at this point and daylight was starting to fade.  I took this picture of the fan spinning:

(https://photos.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-frsVnFQ/0/44ea6dbf/XL/New%20fan%20spinning%20in%20test-XL.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-frsVnFQ/A)

It is difficult to see because the flash stopped the motion and there was very little background light to capture the motion during the exposure.  Finally, I took this video with my iPhone so that you can hear the fan spinning. 

(https://photos.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-nPwwW3M/0/876953b6/M/Sound%20of%20new%20fan%20in%20radiation%20housing-M.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-nPwwW3M/A)

It is mostly quiet, you need to turn off other sounds to hear it, but it will give you some idea of what the fan sounds like.  It is much louder than the old fan and would probably be annoying in a computer.  However, for this application it is actually desirable.  So long as there isn't any other background noises, the fan can be easily heard and that will serve to confirm that it continues to work properly.

The mean life of this fan is something on the order of 7 years, so I'm hoping I won't have to do this again for a good long time!

Cheers, Edouard  [cheers1]
Title: Re: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: Blicj11 on October 24, 2017, 07:32:28 AM
Thanks for the blow by blow description and photos. Glad you are back up and aspirating.
Title: Re: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: xairbusdriver on October 24, 2017, 06:35:44 PM
Heat shrinking is a great method! Did you use a heat gun? I usually just blow on the tubing...

I also like "liquid" 'tape'. It comes in several colors. 'Camouflage' helps hide it from view. [biggrin]
Title: You're welcome! (Re: Using fan to aspirate your temperature/humidity probe.)
Post by: elagache on October 24, 2017, 11:04:22 PM
Dear Blick, X-Air, and WeatherCat station caregivers,

Thanks for the blow by blow description and photos. Glad you are back up and aspirating.

You are most welcome!  However, I'm still behind.  I still haven't gone through the standard maintenance checklist!

Heat shrinking is a great method! Did you use a heat gun? I usually just blow on the tubing...

I bought a heat gun because I needed to make some electrical repairs on da' trusty wagon that required this level of protection.  Heat shrink tubing certainly does a better job of protecting wiring from the elements.

I also like "liquid" 'tape'. It comes in several colors. 'Camouflage' helps hide it from view. [biggrin]

I have some liquid tape as well, but I use it only when nothing else will work.  There are some new crimp style connectors that allow you to avoid some otherwise horrible soldering jobs.  Posi-Products makes some really neat connectors:

http://www.posi-products.com/ (http://www.posi-products.com/)

The one that is really the greatest improvement over the alternative is the Posi-Tap:

http://www.posi-products.com/posiplug.html (http://www.posi-products.com/posiplug.html)

There are a number of situations when you need to tap into an existing wire.  These connectors do in a minute what used to take 1/2 hour of really messy soldering.  When you need to tap into an existing wire on an automobile, trying to solder in the engine bay (or worse) is very difficult  [banghead] and potentially dangerous!  I'll take this smart-cookie solution over that any day!  :)

Cheers, Edouard  [cheers1]
Title: Re: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: xairbusdriver on October 25, 2017, 03:22:46 AM
Quote
trying to solder in the engine bay (or worse) is very difficult
I suspect it’s best done with the engine not running?  [banghead]
Title: When there was no easy to tap a wire. (Was: PC case fan)
Post by: elagache on October 25, 2017, 09:49:48 PM
Dear X-Air and WeatherCat FYI electricians,

Quote
trying to solder in the engine bay (or worse) is very difficult
I suspect it’s best done with the engine not running?  [banghead]

Uh yeah!  That's one of first things to make sure of!  However, even with the engine off, tapping a wire can be a very miserable business.  When I retrofitted our 2000 Century (Coquette) to Phillips LED daytime running lights (https://www.amazon.com/gp/product/B005DX6BKW/ref=oh_aui_search_detailpage?ie=UTF8&psc=1), the controller box needed a tap into the parking light wiring.  LED daytime running lights are supposed to dim at night, the way the controller box determines to dim the LEDs is when the parking lights are on.  Alas, the only place I could find to tap into that wire was in the right next to the plastic light housing.  Trying to manipulate a soldering iron at the edge of the engine bay with fragile plastic and potentially flammable lubricants around was not fun!   [banghead]  However, I did manage to make the connection.  As a result, here are the LED daytime running lights in the daytime:

(https://photos.smugmug.com/ClassicandCustomAutomobiles/Coquette-2000-Buick-Century/Phillips-Daylight-8-DLRs/i-b2Wk334/0/87b68643/XL/Coquette%20with%20DLRs%20working-XL.jpg) (https://canebas.smugmug.com/ClassicandCustomAutomobiles/Coquette-2000-Buick-Century/Phillips-Daylight-8-DLRs/i-b2Wk334/A)

Here is what they look like with the headlights on and thus the LEDs are dimmed:

(https://photos.smugmug.com/ClassicandCustomAutomobiles/Coquette-2000-Buick-Century/Phillips-Daylight-8-DLRs/i-8MMKMJc/0/ab971e9c/XL/Coquette%20in%20%22nighttime%22%20mode-XL.jpg) (https://canebas.smugmug.com/ClassicandCustomAutomobiles/Coquette-2000-Buick-Century/Phillips-Daylight-8-DLRs/i-8MMKMJc/A)

I bought the same kit for my trusty wagon, but the row of LEDs looks too modern for a 50 year old car in my tastes, so I'm trying to come up with something else.  At least for my wagon I was able to use the Posi-Tap connectors (http://www.posi-products.com/posiplug.html) so I've already got the needed tap without any soldering.

Cheers, Edouard  [cheers1]
Title: Re: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: Blicj11 on October 26, 2017, 02:22:38 AM
Nicely done Edouard. Like Fredrico, we love you.
Title: Autumn maintenance (Re: PC fan to aspirate temperature/humidity probe.)
Post by: elagache on October 14, 2018, 11:15:25 PM
Dear WeatherCat station caregivers,

WeatherCat dutifully sends me the reminder email to service my weather station on October 2nd.  I've been trying to complete this servicing since then.  The Weather Envoy battery fiasco was part of this effort.  Today, I finally got around to servicing the temperature humidity probe.  Since I replaced the PC case fan last spring I wasn't sure how much debris the new fan was bringing into the radiation shield and onto the sensor itself.  So felt it was necessary to take the assembly apart to be sure all was well.  I decided to just unplug the cable and let WeatherCat rack up the sensor errors.  Here is what the assembly looked like just off the bracket:

(https://photos.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-Wk2FK4H/0/deaee213/XL/Dirt%20on%20radiation%20shield%20after%206%20months-XL.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-Wk2FK4H/A)

Not very dirty at all really.  Here is the upper part of the assembly where the fan is located:

(https://photos.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-s2Rj2Zd/0/4a06e2fe/X2/Upper%20part%20of%20shield%20disassembled-X2.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-s2Rj2Zd/A)

Some dead insects and spider webs but nothing seriously obstructing the air flow.  I decided to use one of those compressed gas dusters to remove the bulk and settle at that.  Winter is coming, there is no point in cleaning beyond what will get dirty again in a hurry.  Finally here is the original Davis radiation shield disassembled:

(https://photos.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-zpWKnV4/0/442fb4b5/X2/Davis%20radiation%20shield%20disassembled-X2.jpg) (https://canebas.smugmug.com/Nature/Weather/Davis-station-mod-for-case-fan/i-zpWKnV4/A)

It comes together with the components from the top of the photo and ending up with the final solid plate at the bottom of the photo.  My sensor isn't in the normal position that would have come from Davis because the fan required the sensor to be relocated (according to Davis at any rate.)

I need to buff the wax off of the collector cone and apply Rain-X to the interior surface of the cone.  Then at last my station will be fully serviced for Winter.  These days, I guess I can't complain about it taking 2 weeks!

I hope everyone else in the Northern Hemisphere has done their maintenance for Winter.  If not, time is definitely of the essence!

Cheers, Edouard

P.S. I had a surprise when I checked WeatherCat after reconnecting the temperature humidity probe.  It claimed the temperature had jumped 10 degrees from where it was when I started the servicing.  Here is a graph with the anomaly:

(http://www.canebas.org/misc/Capto_images/Temperature%20spike%20caused%20by%20probe%20maintenance%202018-10-14.png)

As you can tell from the photos, the sensor spent a bit of time in the sun while I was servicing the assembly.  That was enough to cause the apparent increase in temperature.  As you can see from the graph, the fan made quick work of getting the sensor back to the correct air temperature.
Title: Re: Using a PC case fan to aspirate your temperature/humidity probe.
Post by: Blicj11 on October 15, 2018, 08:34:07 AM
Once again, thank you for taking the time to photo-document your adventures and share with the rest of us.