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  #41  
Old 23-11-2019, 05:11 PM
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More experimentation this week. I've been researching cloud models and came across a paper that compares a number of models that predict sky temperature for clear and cloudy skies. Most of the cloud based models factor in air moisture content either as dew point or vapour pressure, something I didn't have in my home grown model.

I've been busy trying out the various theoretical models this week and have settled on a couple that seemed to fit my data reasonably well. I've now added the necessary code to my WeatherBox app. I also decided to add a more accurate relative humidity sensor to my arduino project since this is one of the key variables in predicting cloud and the DHT11 sensors don't have a great reputation for accuracy.

It's clear at the moment but supposedly getting cloudy tonight so I'm looking forward to see how the new model goes.
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  #42  
Old 30-11-2019, 05:09 PM
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I feel like I've made some progress on this over the week. I've incorporated and tuned the literature based sky temperature models and I'm getting quite a good fit to my measured temperatures. I've got a bit more tweaking to do on the cloud model but it is also looking quite good I think.

I've also done some better colour coding for the display to change with a set of thresholds I've set.
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  #43  
Old 03-12-2019, 10:47 PM
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I've made some more progress over the past few nights. I've now got a test app writing the Boltwood style single line data file. The significance of that is the existing Ascom Observing Conditions Drivers (available from the Ascom website) will read this file and pass the information to any compliant app (including SGP) so I don't need to write my own Ascom driver.

The data file is very specifically formatted (spacing of the numbers seems to be critical for it to work) so a lot of the effort is in creating a string with the data values in the right places:
2019-12-03 22:40:24.00 C K 14.0 2.0 7.0 1.0 9 13.2 3 0 0 00002 043802.94472 1 1 1 1 0 0

Next step is to link this to the actual live data.

Happy days
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  #44  
Old 04-12-2019, 06:30 PM
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I've got my Boltwood single line data file code incorporated into my WeatherBox app and now have live data feed to SGP.

Ascom is a beautiful thing!

A bit more tweaking on the data being passed through and I'm almost done.
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  #45  
Old 04-12-2019, 08:31 PM
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Sweet! Well done mate!

Is that cloud cover % in SGP window rounded down from your 0.7?
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  #46  
Old 04-12-2019, 08:51 PM
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Quote:
Originally Posted by troypiggo View Post
Sweet! Well done mate!

Is that cloud cover % in SGP window rounded down from your 0.7?
Cheers Troy. The Boltwood system reports Clear, Cloudy or Very Cloudy. They transpose to 0%, 50% 100%.

My app outputs % cloud cover throughout the entire range 0-100% but to use the generic Boltwood single line data driver I've had to translate my figure to their three steps for pass through to SGP.
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  #47  
Old Yesterday, 09:04 AM
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So the Boltwood system is a bit "coarser" than your app, and to use their ASCOM driver you end up having to dumb down your more accurate modelling. Again - well done.
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  #48  
Old Yesterday, 09:12 AM
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good to see your progress with this. arduino is dead simple to get into and tinker with. I often find myself reading academic papers like you did with clouds and can get enough information to be usable to refine part of how i'm measuring and other factors to take into effect. I built a lap timer just to measure tweaks I make to my coding of an autonomous driving robot. ended up having to learn about rolling averages to smooth out sensor noise and using temp/hum measurements to make precise distance calculations across the track as my method of detecting the robot passing by (as opposed to hall sensor or laser line methods but thats the beauty too of arduino you can try all these methods and see which you find most effective for your project.) As you're finding integrating with other systems can impose limits when they only accept certain values but you have the luxury to use the true values in your own custom display while passing modified values to another system calibrated to your projects scope and observations. for example you may take values of 20% as measured and transpose those to 50% so Boltwood reports cloudy.

Plus arduino is such an easy platform to replicate. I mostly use Arduino Uno as my base boards and bought an official one which is nice and stable to use as my development board then get others from ebay which are chinese clones with often dubious construction quality. hooking parts up to the cheaper board and copying the code across and its a functional copy that should give the same results. So for your project you may want to provide the info for others to replicate your build and maybe gather test data for you to help refine your coding. or maybe not if your aim is to profitise your work rather than share. but arduino is dead easy and affordable to pretty much anyone really. there is so much information out there. grab an arduino uno starter kit from ebay and go to arduino.cc and start with simple tutorials doing simple things then tinker with ideas from there. its NOT difficult.
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  #49  
Old Yesterday, 04:23 PM
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Quote:
Originally Posted by troypiggo View Post
So the Boltwood system is a bit "coarser" than your app, and to use their ASCOM driver you end up having to dumb down your more accurate modelling. Again - well done.
I've had to apply their three settings to my continuous measurement for both cloud and light and ultimately the same will apply for wind. I still have the full 0-100% measurement in my desktop app however the interface via the ascom driver I'm using only has the 0%/50%/100% type options.

Quote:
Originally Posted by sil View Post
good to see your progress with this. arduino is dead simple to get into and tinker with. I often find myself reading academic papers like you did with clouds and can get enough information to be usable to refine part of how i'm measuring and other factors to take into effect. I built a lap timer just to measure tweaks I make to my coding of an autonomous driving robot. ended up having to learn about rolling averages to smooth out sensor noise and using temp/hum measurements to make precise distance calculations across the track as my method of detecting the robot passing by (as opposed to hall sensor or laser line methods but thats the beauty too of arduino you can try all these methods and see which you find most effective for your project.) As you're finding integrating with other systems can impose limits when they only accept certain values but you have the luxury to use the true values in your own custom display while passing modified values to another system calibrated to your projects scope and observations. for example you may take values of 20% as measured and transpose those to 50% so Boltwood reports cloudy.

Plus arduino is such an easy platform to replicate. I mostly use Arduino Uno as my base boards and bought an official one which is nice and stable to use as my development board then get others from ebay which are chinese clones with often dubious construction quality. hooking parts up to the cheaper board and copying the code across and its a functional copy that should give the same results. So for your project you may want to provide the info for others to replicate your build and maybe gather test data for you to help refine your coding. or maybe not if your aim is to profitise your work rather than share. but arduino is dead easy and affordable to pretty much anyone really. there is so much information out there. grab an arduino uno starter kit from ebay and go to arduino.cc and start with simple tutorials doing simple things then tinker with ideas from there. its NOT difficult.
Steve,

That pretty much sums up my experience. Have you turned your arduino projects into something more that a prototype - I'm wondering whether the sensors and interface board could be manufactured onto a custom arduino shield? I'm also happy to share what I've done if anyone is interested in giving it a try.
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