Cheap cloud detector?

[Guest peepshow]

I am getting sick of all this cloud.  Sometimes in the middle of the night it might clear for a few hours but I am in dream land at the time.

 

Cloud detectors are quite expensive at around £200.

After some googling and goggling (  ) I find that some detectors work by comparing the ambient temp to that of the ground. 

 

Peltier devices can  be used for this.  They are only a few quid each and the volts output across the plates changes as cloud cover comes and goes.

 

The volts out is normally connected to PC software to control obsy doors etc etc.

 

But I reckon that one can simply detect the volts changes using a simple op amp and that in turn  rings a bell in the bedroom.

So I am going to experiment to knock up a cloud detector for a few pounds, not the hundreds  normally required.

Watch this space.

Edited December 13, 2013 by peepshow

[+Graham]

sounds like a plan to me Richard.

It would also work the other way round for those of us who leave the scope running to get some sleep.

Keep us updated.

[red dwalf]

Look forward to see how you get on with this Richard, good luck with it.

[+Ibbo]

I'm using an Arduino set up like this 

 

http://bildr.org/2011/02/mlx90614-arduino/

 

 

without the capacitor

 

tests based on 3 nights with mine appear to indicate a sky temp of below -5 it is clearing and -8 is worth imaging and -12 is good

 

only problem so far is in fog it was giving -12 ish

 

no bell as yet

Edited December 13, 2013 by Ibbo