Digital Rain Fall Monitor




About: As and electronics engineer I am amazed at how gadets work. Having experience in PIC programming using low level assembly language, I am very impressed at the Arduino platform and how quick and simple it is ...

A Rain gauge is one of those sensors that is a great addition for your DIY weather station.

Finding a stand alone rain gauge is not that common, so I decided to purchase an off the shelf digital rain gauge monitor and remove the rain gauge sensor off it to make my own arduino powered rain gauge monitor.

In this tutorial, I’ll show you how to make a digital rain gauge monitor by using a rain gauge sensor from an off the shelf product, how this particular sensor works and how to read the signal with an Arduino Uno then finally display the result to an LCD Display. So, keep reading to find out how......or Watch the Video below if that's easier.....

Step 1: How Does the Sensor Measure Rainfall

The rain sensor measures rain by collecting a set amount of water in a tipping bucket. When the preset amount of water is collected, the bucket tips the water out and a magnet swings past a reed switch and activates a single count.

This count is read by the microcontroller's input as a pulse. This particular sensor I'm using is set to 0.8mm per bucket of water. The rainfall detected by the rain sensor will vary between manufacturers.

Step 2: Rain Gauge Circuit and Code

The rain gauge monitor circuit is very simple as we only use one pin of the Arduino which is pin 2. As the sensor component is a reed switch, the only circuit required is a 10k pull up resistor to hold the signal to ground when inactive and pull up the signal to +5V when the reed switch is activated.

The code monitors the pin 2 input and every time it is set to high, the total rainfall value is incremented by 0.8mm. The total rainfall value is then displayed on a 16 x 2 LCD Display.

The code and schematic is available from my website at the following link:

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    4 Discussions


    2 years ago

    Would have been much more help to have links to source the tipping bucket sensor and had a cost. Even better would be a project to build your own sensor and give the math to compute volume of the bucket to design your own and also the dimensions of the collector funnel and how that relates to the computation of rainfall rates.

    1 reply

    Reply 2 years ago

    Thanks for your advise. It sounds like if would be a good project to do.


    2 years ago

    Cool Project! A nice digital alternative to other measurement methods. Have you considered weighing the bucket? Weight translates very easily to volume.

    1 reply

    Reply 2 years ago

    Thanks ! Instead of weighing it, I used a syringe filled with water to fill up the bucket to determine the volume that would tip it (that is with the funnel off). In this case it turned out to be about 4.4 mls of water which equates to 4.4g. The interesting thing though, when you place water through the funnel to tip the bucket, it required about 5 to 5.5mls of water. I think this is because about 1/2 - 1ml of water sticks to the funnel and it's mesh/grating and does not reach the bucket.