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Re: Direct sunlight sensor
On 2/11/2015 4:56 AM, rickman wrote:
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Commercially available awning motors are not variable speed. Short of  
modifying one or building one from scratch, I appear to have no way of  
achieving slow awning movement. I have to work with what I can get.

Sylvia.


Re: Direct sunlight sensor
On 11/1/2015 7:39 PM, Sylvia Else wrote:
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They are fast?  Then I guess you need a fast response when in motion,  
slow the rest of the time.

--  

Rick

Re: Direct sunlight sensor
On Mon, 2 Nov 2015 11:39:44 +1100

}snip{

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How about intermittent adjustment?
Let's say every hour (or 30 minutes or whatever you prefer) you switch
on the tracker. It awns, maybe incredibly fast, and then it stops.
After your preferred time window it tracks again.

joe
  
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Re: Direct sunlight sensor
On Sat, 31 Oct 2015 11:56:40 +1100, Sylvia Else

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It struck me this morning that all you need to do is sense the
elevation angle of the sun... half of a typical sun-follower sensor,
then use your PIC to adjust the awning.
        
                                        ...Jim Thompson
--  
| James E.Thompson                                 |    mens     |
| Analog Innovations                               |     et      |
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Re: Direct sunlight sensor
On 5/11/2015 2:23 AM, Jim Thompson wrote:
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I can't accurately position the awning, since I haven't found an awning  
motor that gives position feedback (or any feedback, come to that).  
There are some for roller blinds, but they're for indoor use only.

I'd have to implement something to sense the awning position, and that  
seems likely to work out even more complicated than sensing when the  
awning puts the bottom of the widow into shadow.

Sylvia.

Re: Direct sunlight sensor
On Thu, 5 Nov 2015 19:45:41 +1100, Sylvia Else

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Can you describe the awning and its mechanism?
        
                                        ...Jim Thompson
--  
| James E.Thompson                                 |    mens     |
| Analog Innovations                               |     et      |
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Re: Direct sunlight sensor
On 10/30/2015 8:48 PM, Jim Thompson wrote:
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So why are you using digital media to communicate?  I wouldn't use a  
microprocessor either.  I'd use an FPGA, lol


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My dad had a new car that left him sitting more than once and they  
couldn't find the trouble because it had cleared by the time they towed  
it back to the shop.  After the third or fourth time they cam out to  
troubleshoot it in the intersection where it quit and found the trouble,  
the ECU, of course.  I think they sent it back to GM where they found an  
output transistor was intermittently faulty.  They had no way to detect  
that sort of failure and self diagnose it.  Seems like one more pin on  
the connector and a wire back to an input would solve that problem for  
system critical outputs.

--  

Rick

Re: Direct sunlight sensor
"Adrian Jansen"  wrote in message  
For a fixed installation like this, you dont really need a sensor at
all.  The suns location is completely calculable, all you need is the
date/time and location.

Get the time from a local clock or net server, set the location, and you
can do the geometry from the sun azimuth and altitude to get the angles
for control.
=============================================================

Build in a gps receiver and you've got time, date, location, and direction;  
it's completely automatic, except for height above ground, I guess, if you  
want to fine-tune those first and last few minutes of sunlight.  They sell  
those little gps usb receivers for what, under $40 qty 1, so cost to build  
one into a moderate volume product has to be under $10.  You could even add  
a temp sensor so it automatically stays closed below some threshold to get  
solar heat in winter.

-----
Regards,
Carl Ijames  



Re: Direct sunlight sensor
On Fri, 30 Oct 2015 21:28:35 -0400, "Carl Ijames"

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Except for a cloudy day >:-}
        
                                        ...Jim Thompson
--  
| James E.Thompson                                 |    mens     |
| Analog Innovations                               |     et      |
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Re: Direct sunlight sensor
But if it's winter you won't be extending it anyway, cloudy or not, so you  
won't be "wrong".  I guess you could argue extending it on a cloudy summer  
day would be a waste, but I'm sure there would be a manual override if you  
felt that strongly.

-----
Regards,
Carl Ijames

"Jim Thompson"  wrote in message  

On Fri, 30 Oct 2015 21:28:35 -0400, "Carl Ijames"

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Except for a cloudy day >:-}

                                        ...Jim Thompson
--  
| James E.Thompson                                 |    mens     |
| Analog Innovations                               |     et      |
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Re: Direct sunlight sensor
On Sat, 31 Oct 2015 00:28:30 -0400, "Carl Ijames"

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Arizona weather can be weird... like it'e rained the last few days...
very unusual.
        
                                        ...Jim Thompson
--  
| James E.Thompson                                 |    mens     |
| Analog Innovations                               |     et      |
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Re: Direct sunlight sensor
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The air conditioning in my 2001 Toyota uses a sensor in the top of the
dash, near the bottom of the windshield, to determine how hard to work;
more sun = A/C works harder.  I have seen similar sensors in other
cars, starting in the early 00s.

The service manual says it's a photodiode and implies that the ECU
biases it with +5 V and expects to see 0 to +5 V in return; lower
voltages for more light on the sensor.

The reason I mention it is that for automotive, the design life these
days is probably 10+ years, and whatever it costs gets multiplied by a
volume of 10 to 16 million or so (in the US).  So there are probably
good reasons why they picked a photodiode.

Matt Roberds


Re: Direct sunlight sensor
On 30/10/2015 7:09 PM, snipped-for-privacy@att.net wrote:
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Be able to get them cheap from the wreckers all ready to go given their  
service availability. Test data should give you an idea of their biasing.

--  

Xeno

Re: Direct sunlight sensor
On Fri, 30 Oct 2015 08:09:49 +0000 (UTC), snipped-for-privacy@att.net wrote:

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Our cars use those sensors for lighting control but I don't think the
HVAC is tied in.  A thermostat would seem to work better.
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Re: Direct sunlight sensor
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Looking at the schematic for mine, the solar sensor goes straight into
the air conditioning ECU.  That ECU also has two thermistors of its
own, one for the cabin temperature, and one for (I think) whatever the
heater or evaporator core is currently putting out.  The schematic also
shows the engine ECU and its outdoor ambient thermistor, so I think it's
telling me that the air conditioner listens to that over the bus, too.

How I think it works is that it mostly uses the thermistors and the
desired temperature set by the user, like a thermostat, but that the
solar sensor changes the slope of the curve it uses to drive towards the
set point.  It might also change the overshoot.

In other words, if you're 5 degrees F above the set point at night, it
will run the blower on "low", and stop when it is 1 degree F below the
set point.  If you're 5 degrees F above the set point in the daytime, it
will run the blower on "high", and maybe wait until it is 2 or 3 F below
the set point to stop.  The car company wants those MPG, but they also
don't want sweaty drivers.

Starting in about 2005, things got pretty chatty in a lot of cars... if
there's a sensor plugged into one ECU *anywhere*, most of the other ECUs
can get its value over the bus.  By 2010, for sure.  (This is partly
why Microsoft or Apple or Internet-connected anything, anywhere in the
car, scares me a lot.)

Matt Roberds


Re: Direct sunlight sensor
On 10/29/2015 3:25 AM, Sylvia Else wrote:
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How about using an IR-transparent filter in front of the sensors?

Re: Direct sunlight sensor
wrote:

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The usual thing they use to measure solar energy is a  Pyranometer.

https://en.wikipedia.org/wiki/Pyranometer


For whatever time of the year and the typical irradiance when no
clouds are present at your latitude,  this will tell you what you've
got shining down on it.

boB


Re: Direct sunlight sensor
On 29/10/2015 2:41 PM, Sylvia Else wrote:
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Automotive auto-lights on features often rely on a light sensor on the  
dash which incorporates a UV filter.

They may be LDR's or photodiodes, but either should work.



Re: Direct sunlight sensor


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I once inadvertently made a sunlight detector. I needed a simple  
photo-switch to turn on some LEDs when it got dark, and I made one from  
parts in my junk box - an LDR and a LM3900. I had the LDR connected between  
the positive supply and one of the LM3900 inputs, and I figured that I did  
not need any additional series resistance.

Although the original was used successfully indoors for years I was wrong! I  
later made another one, which I mounted on an outside wall. This worked for  
a few months, but then failed, when with the change of seasons, the LDR got  
exposed to direct sunlight. The resistance of the LDR went so low that the  
current into the LM3900 input was enough to destroy it.

Due to the one-time nature of this detection, I won't recommend it.



Re: Direct sunlight sensor
On Thu, 29 Oct 2015 17:41:59 +1100, Sylvia Else

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Maybe something like this...

<http://www.analog-innovations.com/SED/AwningController.pdf>
        
                                        ...Jim Thompson
--  
| James E.Thompson                                 |    mens     |
| Analog Innovations                               |     et      |
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