Author Topic: Davis areometer info  (Read 360 times)

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Offline dedon

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Davis areometer info
« on: June 12, 2019, 03:39:30 PM »
Found Davis Aerometer at ham swap meet. No part number or brand name. Was able to determine it is a Davis device from pictures on the web. It has a wind direction vane along with wind speed cups. It has a 20' cable with stereo plug on end. I cut the plug off and stripped wires. A black and red wire plus shield. I want to use it with an Arduino board. An Arduino sketch shows another wire used. So perhaps I can't use the device. An ohmeter shows changing resistance between shield and either wire when I spin the cups or move the vane. What model do I have here?
Thanks
« Last Edit: June 12, 2019, 03:41:34 PM by dedon »

Offline Mattk

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Re: Davis areometer info
« Reply #1 on: June 12, 2019, 06:46:32 PM »
Having only a red and black wire using a stereo plug does not sound like a Davis anemometer?

Offline dedon

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Re: Davis areometer info
« Reply #2 on: June 12, 2019, 07:29:48 PM »
You may be correct. But, it sure looks like one. Even the 12.5 inch black rod and bracket that screws onto vertical side of a structure. If not a Davis, it does have 2 working "pots". One for the cups and one for the vane. I think one input of the the Davis unit is connected to Arduino as analog. The other is digital.Maybe I can get the output of other side to go in as analog too.

Offline SLOweather

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Re: Davis areometer info
« Reply #3 on: June 14, 2019, 03:40:13 PM »
It could be from an old Digitar station, which predates the Davis name.

Does it look like this?

« Last Edit: June 14, 2019, 08:12:11 PM by SLOweather »

Offline lightmaster

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Re: Davis areometer info
« Reply #4 on: June 14, 2019, 06:33:04 PM »
It could be from an old Digitar station, which predates the Davis name.

Does it look like this?



Looks like your img url isn't working, says 403 Forbidden when I go to the url in my browser.

Offline SLOweather

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Re: Davis areometer info
« Reply #5 on: June 14, 2019, 08:13:01 PM »

How about now? I saved the image to my own server and relinked it.



Looks like your img url isn't working, says 403 Forbidden when I go to the url in my browser.
[/quote]

Offline lightmaster

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Re: Davis areometer info
« Reply #6 on: June 14, 2019, 09:40:27 PM »

How about now? I saved the image to my own server and relinked it.



Looks like your img url isn't working, says 403 Forbidden when I go to the url in my browser.

Looks good now

Offline dedon

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Re: Davis areometer info
« Reply #7 on: June 14, 2019, 10:32:04 PM »
Yes it sure does! All I have is just the main unit that has cups and a vane plus a long red/wht/shield cable attached, Looks just like in your picture. So, what's the best way to use with Arduino? I found this, a very long white paper.

https://shareok.org/bitstream/handle/11244/48947/Pinkerman_okstate_0664D_14519.pdf?sequence=1&isAllowed=y

Page 62 starts showing how the instrumentation was set up. Page 81 is very interesting. Page 191 show Arduino sketch. Tried it, but neither sensor showed any change on the Arduino Serial Monitor. I think its wired wrong, I need send in external voltage above 9 volts into wind speed side?
Thanks ,,, Don

Offline SLOweather

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Re: Davis areometer info
« Reply #8 on: June 15, 2019, 11:25:03 AM »
The wind vane should be a potentiometer. The anemometer (the cups) should be a reed switch. See if you can use a n appropriate allen wrench to loosen the set screw and pull the cups off. There should be a small magnet in the cup hub, and maybe the reed switch in the housing hub.

Offline dedon

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Re: Davis areometer info
« Reply #9 on: June 15, 2019, 02:45:36 PM »
I found the trouble for the cups part of the anemometer. I needed a pull-up resistor on digital pin 3.
I now see mph on the Serial Monitor as I spin the cups. The vane is still not working. Only 2 wires, red, white and shield (ground) are available from the unit. The white is from the cups part. The red wire goes to the vane.
Using ohmmeter across red and ground, I see 0 to 20K as I turn vane CW. Continuing to turn, meter goes to zero K. Then immediately starts going towards 20 K as I keep turning CW. So this is a potentiometer type vane. Not sure what to do next. As shown in your picture there is a "control unit" with all the parts. I do not have this unit. I want to use what I have.

Offline SLOweather

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Re: Davis areometer info
« Reply #10 on: Yesterday at 12:53:03 PM »
You will also need a pull up resistor of some sort on the direction pot. Ground the shield, red to the pull up resistor, and the other side of the resistor to plus of Arduino power. Then the red/resistor connection goes to an analog input on the Arduino.   

 

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