Rain Detector

It would be handy to be able to have a detector that can give an audible signal when it starts to rain.
I often have sports kit outside drying (Scuba, boat etc) and can't rely on it staying dry long enough to dry kit.
I have found a link to one project http://www.techlib.com/electronics/raindetectors.htm
Anybody anything better .... the key would seem to be the sensor ... large enough surface are to catch first few drops of rain, stable enough not to corrode in a couple of weeks.
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Rick Hughes coughed up some electrons that declared:

Stainless steel would last forever, more or less. When I was a kid, I made a water level detector for a caravan water tank (Aquaroll) with 5 bits of stainless rod bent around the pipe-straightener that dipped in the container. One common and 4 sensor points. Connections were done with crimped stainless wire, sleeved and run out of the container, then soldered into a DIN plug. Worked very well, never corroded.
Anyway I digress.
Perhaps get something like (anything will do as long as it's got stainless rod):
http://cgi.ebay.co.uk/NEW-PATON-CALVERT-STAINLESS-STEEL-WIRE-DISH-DRAINER_W0QQitemZ200249636058QQihZ010QQcategoryZ122935QQtcZphotoQQcmdZViewItem?refid=store
Cut short strips, solder wires on the ends (Bakers Fluid and silver solder to tin the stainless worked for me, but that's dated information, may be other ways).
Lay in a pattern like this:
---------------- ===============---------------- ===============---------------- =============== Connect the --------- together, connect the ============ together, but separate from the ----------
Epoxy down on a bit of plastic (outside of a waterproof box if you want keep it self contained, with the electronics inside). Space rods so that a drop of rain can couple two rods.
If you don't fancy trying to solder the rod, what I did was hacksaw a 1/8" slot in the end, then use a heavy vice to crimp a bit of wire in the slot. If you're using copper wire, a bit of solid core from some mains twin+earth might work, but cover the crimp with epoxy.
Well, that's my theory. Sure there'll be many more equally good ideas. The above will cost you a few pounds depending if you get lucky at the pound shop for the stainless and whether you need to buy appropriate solder and flux.
Cheers
Tim
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We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Rick Hughes"

Stainless steel probes - I've never tried soldering to stainless, it might be ok.
--
Dave
GS850x2 XS650 SE6a
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on
Isn't a Scuba kit supposed to be wet? and how do hang a boat on the washing line?
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George wrote:

You'd be amazed how much a wetsuit will smell if left damp for a few days. And even synthetic sails will get mildew stains.
OP might like to google for wetsuit enzyme too.
Andy
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when in use yes :-)
afterwards you need it to dry ... as to boat, typically covers left off it trying to dry it out, usually gets close to dry ... then it rains, and before I notice ... 'tis all wet again.
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Rick Hughes wrote:

Veroboard with alternate strips commoned to each sensor wire?
Alternatively, a well-trained cat[*] that doesn't like getting wet and will come and ask to have paws dried, will alert you to a change in weather conditions.
3rd option: a canopy over the washing line, that descends when a piece of blotting-paper gets wet.
Owain
[*] this is of course an illusion, you find a cat that doesn't like to get wet and has trained you to dry its paws whenever it comes in.
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That was the basis of one in Everyday Electronics which I made well over 30 years ago. You need to heat it too (a few low power resistors are sufficient), or it can takes ages to dry out and stop reporting rain, when the rain stopped ages beforehand, and it might otherwise be triggered by condensation.
I think I've seen a simple module in Maplin which works much the same way.
--
Andrew Gabriel
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On 30 Aug, 18:37, snipped-for-privacy@cucumber.demon.co.uk (Andrew Gabriel) wrote:

I made the same one ... I even still have that issue of the magazine ! The problem will be long term stability with veroboard in open air ...
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So do I, in that I've never thrown any of them away since 1972. I have most of the Everyday Electronics up until it stopped, and then a complete set of Elektor for some years following. Also much less complete sets of Practical Electronics, Practical Wireless, and ETI, when they contained something which grabbed my attention. I haven't routinely bought any for last 10 years or so now though, but I do regularly design and build my own electronic projects.

I recall seeing a built potted module some time back (don't think it was Velleman). It was quite low power suitable for battery operation, but had a separate connection for the drying heater, which made it non-battery suitable if you wanted to use the heater.
--
Andrew Gabriel
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My collection of PE must date back to the late 60s elektor, ETI, EE and WW somewhat more sporadic. I still subscribe to E&WW, but I don't think I'll renew the subscription when it runs out
I think it won't be long until they are all destined for the great skip in the sky, along with all the IEEE publications etc
Too much 'kin junk !

--
geoff

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On Thu, 4 Sep 2008 21:57:54 +0100 Geoff wrote :

And not be able to look back on all the Amstrad ads and the wonders that once were
"1970 Amstrad's first electrical product, the popular Amstrad 8000 amplifier, priced at pounds 17.70. Sugar says later: "It was the biggest load of rubbish I've ever seen in my life."
1974 Begins marketing the 6000 and 7000 stereo cassette decks, which sell well through the new chain of Comet Stores. They include a "chrome" tape button that is not actually connected to anything.
1976 The EX range of AM/FM tuners, featuring a meter to indicate the sound quality. In fact they showed perfect sound no matter what the signal quality."
http://findarticles.com/p/articles/mi_qn4158/is_20000330/ai_n14286018
--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk


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OK .. if we are going nostalgic.
I bought my Sinclair Black watch kit from an Add in Practical Electronics - really cool :-)
I bought an Haversonic stereo amp kit from Practical Electronics ... only took about 6 months to build and get working, using of course a trusty twin beam scope and Avo 8.
I buily quite a few variants of John Linley Hood projects .. he was the manin man of audio designs. (not sure if he is still around)
I have serveral years worth of ETI ... which I thought was the best of the bunch until it went EPROM & micropocessor based on everything ... so stopped buying it in mid 80's (is it still going ?)
Watford Electronics was the way of the future - sold everthting !
Have the first few years worth of issues of Everday Electronics, staryting with issue 1 and free veroboard kit ! .. .still has pack of resistors stapled to front page !
As somebody else said ... proably time to put them all in recycle bin.
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A legend in his own linear response

Which was different to Tomorrows World at the time, how exactly ?

Cardiff Road was 5 minutes walk - I went past the place a fortnight ago

And the resistor wire bending former, and ...

memories, eh ?
--
geoff

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OK ... went to MAPLIN web site they do sell a Velleman water detector kit, which is totally useless ... it has a simple 2 copper wire detector ... when it's wet it switches a single transistor to sound a buzzer .... It will keep sounding untill it dries, which in UK Summer means battery will not last very long.
Come on guys somebody must know of a better sensor ?
Now if sombdoy knew how to get a car water detector working that may be a good plan ... I have a glass roof to kitched & conservatory so plenty of places to put it.
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I bought a water detector in lidl about five weeks ago, they were ~5. Small sensor connected to a battery box with a chime/alarm in it. I suppose it would make a rain alarm but the surface area is a bit small. I expect it would work with a strip board wired alternately to increase the area. They were also marketed as bath overflow alarms so you may get something similar in boots.
It would certainly work if you put the sensor in the gutter once the water reached there.
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Put a big capacitor in series with the buzzer, then the buzzer will only sound until the cap charges.
Also put a high value resistor across the capacitor to allow it to discharge, or it will only work once :)
cheers, Pete.
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This link may help, http://www.fordscorpio.co.uk/autowiper.htm
Don
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On 30 Aug, 18:37, snipped-for-privacy@cucumber.demon.co.uk (Andrew Gabriel) wrote:

The only one I could find on MAPLIN was the Velleman MK108 kit ... http://www.velleman.be/ot/en/product/view/?id=338493
The pdf manual (one page) makes this seem very basic, but has no details of the sensor, maybe I'm being unfair and the sensor is sophisticated and does it all .... the circuit seems so simple, that I would assume buzzer sounds continuously until rain stops ... that is a bit of a pain.
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Maplin did not have anything other than a simple 2 wire detector - too insensitive and once wet would continue to 'trigger in UK weather not much use.
An update ... in case anybody does a similar search in future ... found a detector module on line ... which has a built in heater to dry it when rain stops:
http://www.kemo-electronic.com/en/module/m152/index.htm
example of it being used is on
http://www.weather-above.com/Rain%20duration%20complete%20with%20heater.html
an on-line rain detector project is :
http://www.techlib.com/electronics/raindetectors.htm
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