Rain gauge - will this work
computer guy
Posts: 1,113
I need to measure the level of rain.
I have designed this circuit however since I am still learning some of the basic electronic laws I do not know if it will work.
Could someone please take a look and tell me if it will work.
Thank you
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Post Edited (computer guy) : 1/11/2008 9:17:37 AM GMT
I have designed this circuit however since I am still learning some of the basic electronic laws I do not know if it will work.
Could someone please take a look and tell me if it will work.
Thank you
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Check out my robot using the propeller RECONAUTOR
Post Edited (computer guy) : 1/11/2008 9:17:37 AM GMT
bmp
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Comments
The example in "Applied sensors" is a bit overboard for my liking. I am also limited to a fairly small space and 4(555 timers) will take up a lot of room.
Thank you
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Post Edited (computer guy) : 1/11/2008 10:57:53 AM GMT
Some use Earth as the return .. low current ..
Google it and you will find out why...
Clue .. it has something to do with electr....
But there is nothing wrong with your principle.. like the drawing Anthony..
cheers
Ron Mel oz
Couldn't find anything with google.
Ron, would you be interested in purchasing something from me for a change - http://forums.parallax.com/showthread.php?p=698795
You could put them in with your orders, as a gift to your customers. Just a thought.
Than you
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Check out my robot using the propeller RECONAUTOR
Once the water reach a specific weight it tilts to dump the water out and as it does it presses a switch. Timimg between 2 impulses will give you the downpour rate.
In your case you have to make a hole on the contanier, and calibrate it to a specific mesure, that may prove trick. hole too small, and it will top up very quickly, hole to big and it won't give a precise measure.
What do you mean by hole? The only hole in my design is at the top of the gauge and that is to let water in.
Thank you
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with a lot of experience in the field of ambient measuring systems i see two critical points in your design:
- DIRT! since water tends extremely to accumulate this stuff your contacts will not work for a long time, until you clean the contacts often.
- and how do you empty the container? Normally this kind of systems are working continuously, so you will need to poor the water every now and then.
By the way: the standard area (EU) for a rain gauge is 200mm2
and a second hint: If using EAGLE (like i do since over 15 years) for creating bitmaps you may use the .PNG format which makes the files much smaller!
Saluti Joerg
Some form of valve will probably be added to empty water.
As for dirt, due to the size of the contacts I figured dirt would not be a problem.
Thank you for the advice with Eagle, will export as PNG next time.
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You could go optical, have some lasers/leds on one side shining at a photocell on the otherside. I assume water would refract enough of the light that when it covered that portion of the sensor it would block it.
Float bulbs could work similar.
We use tipping buckets. Basically a "catch" at the top drops to a funnel that restricts the flow enough so that the 'force' of the water doesn't falsely tip the "bucket".
The "bucket" is basically a couple of small "buckets" on a see-saw. There are some set screws to adjust just how much water it takes to tilt the see-saw. We typically set it for 0.2mm of rain. As the bucket tips, there's an arm with a magnet on it that triggers a mercury switch (we use mercury to prevent bouncing contacts; could easily use a reed switch).
The nice thing about tipping bucket types, is that you can determine rain rate by the number of tips in a given timeframe.
The other style of precip measurement we use is a weighing gauge. Some are encoder read (a scale system pulls an arm connected to an encoder, the heavier it gets, the higher the encoder goes) and others are hanging wire types (a vibrating wire; as the bucket gets heavier, the frequency of the wire goes up -- think playing a guitar...tighten the string and it's pitch/freq goes up).
Hope that helps!
Cheers
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<FONT>Steve
What's the best thing to do in a lightning storm? "take a one iron out the bag and hold it straight up above your head, even God cant hit a one iron!"
Lee Travino after the second time being hit by lightning!
There might be easier ways to sense the level of water where you would not need to worry about contact oxidation or impurities left on the electrodes through evaporation. Not to mention electrolysis effects with electrodes directly in contact with your fluid.
check this link...
http://www.parallax.com/Portals/0/Downloads/docs/cols/nv/vol1/col/nv27.pdf
If you are using a Propeller, it could even be easier than the link mentioned above (<- read CD4060 IC not even required)· ... If I get a chance this weekend I will test this.
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Beau Schwabe
IC Layout Engineer
Parallax, Inc.
Post Edited (Beau Schwabe (Parallax)) : 1/11/2008 4:54:30 PM GMT
But as mentioned many times here, you HAVE to use AC for a more professional usage - and best platinum electrodes as well
Post Edited (deSilva) : 1/12/2008 2:58:59 AM GMT
http://www.weathershack.com/education/tipping-bucket-rain-gauge.html·
Quantum now seems to focus on the multi-key decoders, but I see no reason why they could not be used for detection of multiple levels on a non-contact basis. When you look at the description of those chips, you will see that they talk a lot about rejection of signals from water films. Films are in fact the bane of capacitance based water level sensors. It might work fine at first, but after a while a thin layer of crud (salt, minerals, dirt, algae) builds up on the detection surface. That forms a conductive path that extends considerably above the level of the water that you want to measure , or onto a neighboring key if it is a keypad. The effect of that film can vary with temperature and humidity and with the passage of time. One solution to that problem is to operate the detection electronics at a very high frequency or with very short pulses. The distributed thin film acts kind of like a distributed network of Rs and Cs, and it cannot respond as fast as the main element. Those distributed Rs and Cs act kind of like "soakage" in a capacitor. System identification requires separating the fast responding from the slow responding elements. The nice thing about the capacitance methods is that they do avoid the corrosion issues and the miniature batteries that are formed in corrosion layers.
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Tracy Allen
www.emesystems.com
Just one question, after looking at this link I am a little confused how you are supposed to get the water into the bucket.
Could someone please explain this. (steve_b)
A side on diagram of the whole assembly might help.
Thank you
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Post Edited (computer guy) : 1/12/2008 11:07:33 PM GMT
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Tracy Allen
www.emesystems.com
Post Edited (Tracy Allen) : 1/13/2008 12:04:29 AM GMT
Your Diagram also answered my next question, obviously the buckets alternate and the reed switch detects the change over.
This should be fun (Hardware shop visit).
Now that I know how they work I might just buy a rain gauge and interface it with the propeller (like a normal switch I presume, 10k pullup).
Thank you
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Thank you
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Post Edited (computer guy) : 1/13/2008 2:24:56 AM GMT