Connecting RJ-11 plug of Davis 7852 Rain Collector to Arduino

Hi

We are creating an automatic weather station (AWS) and so far we have interfaced the Temperature, pressure, humidity and light sensors to an Arduino Uno Board. Now we want to interface a Davis 7852 Rain collector as well.

The rain gauge link is here : http://www.scientificsales.com/7852-Davis-Rain-Gauge-p/7852.htm

This is supposed to be used with Davis supplied console. However we want the output to come to one of Arduio Pins. The bucket has a tipping mechanism (A reed switch) so I believe they just send a high voltage when the switch closes. The document mentions following for cable and connector.

Cable Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-conductor, 26 AWG
Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Modular connector (RJ-11)
Black . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Unused
Red . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Switch terminal
Green & Yellow. . . . . . . . . . . . . . . . . . . . . . . . . . . . .Switch terminal

Now we want to snip the wire connected to modular plug and interface it to Arduino. Have anyone experience in connecting RJ11 plug to Arduino UNo? What are the Gotchas and how to test with a multi meter?

Some links I found
http://tom-itx.dyndns.org:81/~webpage/pdf/1wire/raingauge%20conversion.pdf
http://www.aprsworld.com/wind2/documents/davis7852.php

Much Thanks

/rajeev

Answering since we have interfaced the Davis 7852 now and if you are attempting the same then it may be of some help.

The RJ11 wire coming from Davis 7852 has 4 wires - R,B,G,Y
Black is not used. So just put the RJ11 connector into a socket pin and then

G+Y - fuse together as one wire - wire1
R - is another wire - wire2

Think of the Rain Gauge as a switch with these two wires, wire1 and wire2 now.

Hello Good evening, I'm trying to connect "the rain collector of Davis" to arduino, could you tell me how you've connected and if you have some code to make it work? Thanks in advance.
Greetings.

Every bucket based rain meter I've ever seen you push VCC down one wire (the red one in this case) and then tie the other wire to an interrupt capable pin. Every tip of the bucket equals some quantity of rain, and you just count the interrupts as they happen to measure accumulated rainfall.

Some things to think about though is you need to "expire" your counts over time. I've seen this done with a 60 element array and each element represents a minute. If the minute has changed then you zero the element and add your count, if the minute hasn't changed you add your count to the element.

This give you rolling array that shows you rainfall in the last hour. You need to obviously total all the elements of the array and multiply them by whatever a single bucket holds to get actual rainfall.

There are probably better ways to do this but this one is fairly simple to understand and debug.