Topic: Adding LED (or?) to shield fan help

[WeatherHost]

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Don't get sand in your eyes.

[Bashy]

 

It was the dream i had whilst i was sunbathing earlier, ha ha ha

[Bashy]

Hi Mick, good to hear from you, hope you are feeling better?

I'm gonna get one of those just to have a play with, a shame they don't use light as a control, would have been perfect to slow the fans down at night. I have 1fan in the Davis shield and 2 in the Apogee effigy I made, I shouldn't mock it, it actually works as good as a the Davis but seen as all 3 fans are running 24/7 at full power, that's a fair few watts wasted

[CW2274]

Hi Mick, good to hear from you, hope you are feeling better?

I'm gonna get one of those just to have a play with, a shame they don't use light as a control, would have been perfect to slow the fans down at night. I have 1fan in the Davis shield and 2 in the Apogee effigy I made, I shouldn't mock it, it actually works as good as a the Davis but seen as all 3 fans are running 24/7 at full power, that's a fair few watts wasted

fan  speed  in automatic  mode  will switch the fan of when it it's the lowest
Temp you set
Mick

Aspiration is mainly for combating solar insolation in light or no wind, not the temperature.

[CW2274]

Hi Mick, good to hear from you, hope you are feeling better?

I'm gonna get one of those just to have a play with, a shame they don't use light as a control, would have been perfect to slow the fans down at night. I have 1fan in the Davis shield and 2 in the Apogee effigy I made, I shouldn't mock it, it actually works as good as a the Davis but seen as all 3 fans are running 24/7 at full power, that's a fair few watts wasted

fan  speed  in automatic  mode  will switch the fan of when it it's the lowest
Temp you set
Mick

Aspiration is mainly for combating solar insolation in light or no wind, not the temperature.

The speed Control module  comes with  4 temperature sensors
Each  fan out put can be controlled by the external temperature sensor

Fan  speed is calibrated as to not interfere with the air temperature and humidity

No sir, you're still missing the point. The temperature should NOT dictate whether the fan runs or not, it's whether the radiation shield is in the sun with light or no wind (even at night, there's benefits). Temperature is basically irrelevant.
BTW, how are you calibrating the fan speed to not "interfere" with the temp or humidity? That would be science I've yet to see.

[Bashy]

Hi Mick, good to hear from you, hope you are feeling better?

I'm gonna get one of those just to have a play with, a shame they don't use light as a control, would have been perfect to slow the fans down at night. I have 1fan in the Davis shield and 2 in the Apogee effigy I made, I shouldn't mock it, it actually works as good as a the Davis but seen as all 3 fans are running 24/7 at full power, that's a fair few watts wasted

Hi

You  don't need a light sensor for night
You can set it so when the temperature  goes down  it will slow the fan   you set a min  temperature
Than a high  temperature      fan  speed  in automatic  mode  will switch the fan of when it it's the lowest
Temp you set

Mick

Hi Mick, i see an issue there, either constantly having to adjust the temp to suit or put up with the fan staying on
If you set the fan to go off/slow down at say 15C or below, some nights its higher than 15C, so it would stay on
This is why i thought about the light sensor, but i cannot find a controller that will do what i am after, i.e.
automatically control speeds using Photoresistor, i can only find on/off controllers, they must be around because
Apogee uses one for their shield, perhaps they make them themselves??

[Bashy]

Guys, would a 555 slow the pulse so that the pulse would be visible through the LED regardless of the speed of the fan?

[CW2274]

The fan I use pulls at 67CFM (no idea what to convert that to), has a red LED on the transformer to let me know it's getting power, and pulls a whopping 4.7 watts, less than a night light. Granted the LED only signifies the power is there not that the fan is actually spinning but I can hear it sucking air into the ISS from 10 meters away. I run mine full bore 24/7 365, and think the variable speed is a waste of time IMHO.

[Bashy]

Im not so sure it needs full tornado at night though, what with there not being much solar radiation an all
but, having said that, if you have any close structures that could/can/will give off any radiant heat then yeah
i would leave it at full bore, 67CFM is a hell of a lot of airflow, can the shield even pull in that amount of airflow?
what i mean is, you could be wasting x amount if the shield can only do 36cfm max, ps your fan is using 1.7kw a year lol

Q. What size fan (mm) did you use and how did you fit it in the round hole securely?

I went for the 80mm (square) and cut off the corners until it just fit, snuggly
I would have gone for the waterproof ones but i can only find reasonably priced ones over in the US
IP67 i think they are, only about $15 but then they want $10-$30 shipping

[DanS]

" but, having said that, if you have any close structures that could/can/will give off any radiant heat then yeah
i would leave it at full bore, "

It's easy to think radiation shield fans cool down the air around the sensors when actually the fan's function is to keep the air inside the shield as close as possible the outside surrounding ambient air temperature. So if you're mounted close to a structure generating additional heat then, if the fan is doing it's job correctly, it will be pulling in that additional heat and passing it through, being measured.
The fix wouldn't be fan speed but shield relocation.

[Bashy]

But thats not what you want and defeating the object and certainly against siting rules for this very reason.

Also, for all intents and purposes, the idea of the fan is to cool the air going over the sensor, think about it,
i will leave that with you for a minute.

yes/no?

OK, why would you want to add a fan in the 1st place?
It most certainly wasnt because your sensor was reading too cold, i dont think i have heard of anyone adding a
fan to their shield because it was reading too cold. I, on the other hand added one (two) to my home made shield
because it was reading 2C above.

You add a fan to bring in outside air to replace the warm, standing air on a warm windless day, in effect, that is the
primary function of a FARS

Going back to what i said though, could be wrong, could be right, depends on how close to said structure, i mean,
you dont want the fan to be bringing in the radiant heat, but on the other hand, you could be far enough away that
the power of the fan could in fact counter that radiant heat with cooler air. As long as it achieves its intended purpose
and that is to match the true air temp as closely as possible, im not so sure it matters

[CW2274]

Q1 67CFM is a hell of a lot of airflow, can the shield even pull in that amount of airflow?


Q2. What size fan (mm) did you use and how did you fit it in the round hole securely?

I went for the 80mm (square) and cut off the corners until it just fit, snuggly

To answer both Q1 and Q2, I initially sealed this fan around the sides with rope putty for greater flow but achieved the opposite, the flow was inhibited by the fans power (back pressure) so I removed the putty leaving a "square peg in a round hole". I verified this by my watt meter seeing that the draw was normal unplugged, but drew ~25% more current plugged up.
This is the fan. http://www.ebay.com/itm/80mm-25mm-New-Case-Cabinet-Fan-Kit-110-115-120VAC-67CFM-Cooling-BB-8025-1766-/380794571711
I merely trimmed two bottom corners off slightly and it fits like it was meant to be.

[CW2274]

So if you're mounted close to a structure generating additional heat then, if the fan is doing it's job correctly, it will be pulling in that additional heat and passing it through, being measured.
The fix wouldn't be fan speed but shield relocation.

Exactly. I've said this countless times here, a fan will only show a poorly placed siting more accurately, faster.

[Bashy]

Thanks for the answers, I had to take off 4 corners i believe, still a tight fit at that
I am also no thinking that the 4000rpm fans are in the OS shield and not the Davis
I think those are only about 2k and very quiet, hence the need for some visual notification

I am hoping the new resistors will be here today, but i also ordered some 12v LED's too
so the resistors wont be needed after all, still, gives me somma to play with

So if you're mounted close to a structure generating additional heat then, if the fan is doing it's job correctly, it will be pulling in that additional heat and passing it through, being measured.
The fix wouldn't be fan speed but shield relocation.

I have seen the opposite, time and time again, when i have had too high temps and added a fan
i have instantly seen a drop in temp

Where my OS is sited, there is a fence to the north, about 14ft and a fence to the east at about 10ft
and the summerhouse to the south at about 12ft, the only decent wind would be from the west, this
too is not clever as there is a 6ft fence at about 40ft away. In full sun, mid afternoon, both fences
are baking and theres some heat from the summer house from about 3pm, so you can imagine that my
sensor is basically in a box, any light winds will just eddy causing any radiant heat to just circulate
in this box, granted some will refresh but some stays, this was proven when i couldnt shake off
higher than normal temps in this part of the garden, i have managed to get it down to a max of +1C by
installing 2 4k fans in the shield top and bottom, bear in mind that this is not your normal plate shield.

This is pre Davis and new mast days and just to show the summer house, ignore the mast and shield



This is where the OS is sited of which is just to the left of the summer house.

[Bashy]

Completed the wee project, this is my first ever circuit board so go easy on me....

I decided to go with 12v flashing led's because if the light is flashing it means that the fan has stopped turning
and so does light off (its both or none) but when the light is continuous (no flash) it means the fan is running
ok, due to the speed of the rotations it means the flash is so fast you cannot see it, hope that makes sense?

The only down side is, i wasnt told that the flash is a alternating between 2 - 4 styles of flashing lol who cares.....

I took one resistor out but I also believe there is no need for the other resistor either, not even sure the  diode is needed either, but left them for health and safety reasons

This is how it works....

All OK = 2 lights working, 1 flashing (constant live) one continuous (fan is running)
Fan problem = 1 light flashing, Fan light off
Fan problem = 2 lights flashing, There is live but fan is not turning
psu or cable issue = both lights out

Finished prototype
https://youtu.be/6lecM_GfoGc

Finshed
https://youtu.be/xAxDVY8hlVc

Big thanks to all that helped

[Bashy]

Board closeup

[Phil23]

Been thinking about this solution for a while & not commenting.

Not sure what type of solution would work for me.
The blinking LED, or LED in general for me has the visibility issue; I can't see it from......

At present it I walk up to my ISS I can faintly hear the fan running.
That makes me think, what about a small Piezo driven by the Tacho signal, producing a more audible sound.
Not invasive, and also able to be extended by wires.

The other though that comes to mind on the electronics front is using a watchdog timer chip.
Possibly driving a much more powerful LED.

The LED could then stay off while ever the watchdog is reset within the timeout period.

Still haven't got the right idea that would suit myself.

At present I only have DFARs, & on the gloomy days often wander over to see if it's actually running.

Phil.

[Bashy]

Been thinking about this solution for a while & not commenting.

Not sure what type of solution would work for me.
The blinking LED, or LED in general for me has the visibility issue; I can't see it from......

At present it I walk up to my ISS I can faintly hear the fan running.
That makes me think, what about a small Piezo driven by the Tacho signal, producing a more audible sound.
Not invasive, and also able to be extended by wires.

The other though that comes to mind on the electronics front is using a watchdog timer chip.
Possibly driving a much more powerful LED.

The LED could then stay off while ever the watchdog is reset within the timeout period.

Still haven't got the right idea that would suit myself.

At present I only have DFARs, & on the gloomy days often wander over to see if it's actually running.

Phil.

These blinking LEDs are very bright, but still, daytime, bright sun, i would struggle, let alone you, but i am
toying with the mounting idea at the moment, i dont know if to mount it attached to the underside of the
fars or somewhere lower say under the eves of the summer house, either way, i should be able to see the
LEDs from within the house at about 10m as both places are out of direct sun light

The pezo will/should work, but bear in mind it will be constantly on, not beeping like an alarm does due to
the speed of the fan, it takes a fan to be nearly stopped before it will register as a pulse

[Bashy]

Mount those LED's in BLACK bezels and you'll be able to see them in daylight...at a distance.

Thanks, but wont that mean adding holes,  something i didnt really want to do, but i think they
came with bezels or was meant to , i dont remember seeing any, but then again, if folks cannot
see these in daylight, it means they are registered blind, although i am yet to do a daylight test
but suffice to say, they dazzle you enough to having to wait a while before you can carry on  lol

loads of buts in there ha ha ha......

[CW2274]

Hi Mick, good to hear from you, hope you are feeling better?

I'm gonna get one of those just to have a play with, a shame they don't use light as a control, would have been perfect to slow the fans down at night. I have 1fan in the Davis shield and 2 in the Apogee effigy I made, I shouldn't mock it, it actually works as good as a the Davis but seen as all 3 fans are running 24/7 at full power, that's a fair few watts wasted

fan  speed  in automatic  mode  will switch the fan of when it it's the lowest
Temp you set
Mick

Aspiration is mainly for combating solar insolation in light or no wind, not the temperature.

I decided to remove the speed controller from my system and just use a small fan running on a reduced voltage
24/7
I have been monitoring the temperature in a shaded area using a traditional Sheath pattern  thermometer And made sure that the fan is not influencing the aspirated temperature and humidity sensors

So are you saying that running your fan faster made for more inaccurate readings? If so, I certainly don't seem to experience that, actually quite the opposite.

[CW2274]

Hi Mick, good to hear from you, hope you are feeling better?

I'm gonna get one of those just to have a play with, a shame they don't use light as a control, would have been perfect to slow the fans down at night. I have 1fan in the Davis shield and 2 in the Apogee effigy I made, I shouldn't mock it, it actually works as good as a the Davis but seen as all 3 fans are running 24/7 at full power, that's a fair few watts wasted

fan  speed  in automatic  mode  will switch the fan of when it it's the lowest
Temp you set
Mick

Aspiration is mainly for combating solar insolation in light or no wind, not the temperature.

I decided to remove the speed controller from my system and just use a small fan running on a reduced voltage
24/7
I have been monitoring the temperature in a shaded area using a traditional Sheath pattern  thermometer And made sure that the fan is not influencing the aspirated temperature and humidity sensors

So are you saying that running your fan faster made for more inaccurate readings? If so, I certainly don't seem to experience that, actually quite the opposite.

What I'm really saying is all boils down to your location

I disagree but glad you've "solved" your issues.

[Bashy]

Looks like i have the SHT31 sensor

I have now complete the LED mod and it's running great, I can see it from in side the house too

Bottom led is power and the top one is fan rotation
If it goes it or flashes like like the bottom one then I know the fan has stopped, thanks for everyones input, I appreciate it

 Now to think of another hack mod, I have aquired a lot of resistors that need using up lol

[Bashy]

Just like to say, much to my dismay, the LED mod works very well, much so that it look likes the fan has stopped
I had a feeling it didnt have much longer left, it must have finally given out as one of the LEDS has now gone out
either that or that LED has blow, will have to check that 1st....

[Bashy]

That sounds like a good plan Mick, it means it would work with the standard Davis fan
I would be interested  in the schematics once you have created it please?

[Bashy]

Mmm, now puzzled, the led is lit again this morning dying the fan is working again, wonder if the lightning last night gave it a jump start......