16

If you're open to a more mechanical solution, I'd suggest building a "tipping bucket rain gauge", best explained by a picture (source: https://www.researchgate.net/figure/Sideview-of-tipping-bucket-Rain-Gauge_fig4_304297354): This should be relatively easy to build and it's trivial to read this electronically by detecting the time it takes to tip. ...


12

Upon reading the question my first thought was, please define what is meant by "how hard is it raining?". The answers to the question Is there a consensus on the “heaviness” of rain? list rain intensity units as being L/m2 or mm/h, which are effectively the same thing (mm/h can be converted to L/m2) and I'm not disagreeing about either. My initial ...


12

One way to do that is to estimate how much water is changing. If you can ignore the spill over, then that is approximately how much the puddle is changing. Another idea you can use is to measure the changing weight of a rain gauge (that will need to be emptied daily, unless you can rig something that will do that for you). The faster the weight increases, ...


12

It's not perfect, but a simple solution to the issue of a puddle building up on the resistance plate is to tilt the plate a bit, so that instead of the water building up on the plate it runs off. Your device would then look for sudden drops in resistance, indicating that a droplet has formed on the device, followed by the resistance rising again after the ...


5

A 'video disdrometer' is a device for characterizing raindrop size distributions. Professional versions (e.g A 1D distrometer) can use a video camera to image the shadow cast by water droplets moving in front of a bright light. So one DIY approach might be a camera imaging rain drops falling through a gap. Delft university have put up an instructable for an ...


5

I would approach this by counting pings on a plate with an attached piezo or microphone. The amplitude of the ping will give the volume of the drop and the number of pings the drop quantity. This is a more robust real-world interface than an electrode sensor.


5

If there was a worldwide standard, then WMO would have imposed it to its members. Here are the definitions in the American (NOOA/NWS) standard: http://www.njweatherscan.com/definitions_of_precipitation.htm Light rain: falling rate of less than 2,54 mm/h. Moderate rain: falling rate of more than 2,8 mm/h, but less than 7.6 mm/h. Heavy rain: fallin rate of ...


4

The German Weather Service (Deutscher Wetterdienst, DWD) provides the following definitions: Heavy rain is defined as large amounts of precipitation during a fixed period of time. [...] The DWD issues warnings of heavy rain using three categories: heavy rain: 15 to 25 l/m² within 1 hour or 20 to 35 l/m² within 6 hours severly heavy rain: 25 to 40 l/m² ...


4

I sort of accidentally did this in one of my projects in a complicated, backhanded sort of way. I installed 16 soil moisture sensors in my yard as part of an attempt to track the distribution of water in the soil of a flower garden. The sensors are battery powered. They transmit their data via Bluetooth Low Energy to a couple of WiFi enabled control nodes in ...


4

You are expecting too much. Weather forecasting has become quite reliable. There are exceptions. One exception is predicting what will happen more than seven days into the future. At ten days into the future, forecasts remain pretty much a random guess. The 1960s discovery that weather is chaotic (Predictability: Does the flap of a butterfly's wings in ...


3

You could connect a funnel to a water wheel. The faster it spins the higher intensity of the rain. This sensor was selected randomly, as should not be consider something I specifically endorse. https://usa.banggood.com/TZT-5V-Piezoelectric-Film-Vibration-Sensor-Switch-Module-TTL-Level-Output-Geekcreit-for-Arduino-products-that-work-with-official-Arduino-...


2

Weather prediction has been (https://www.ecmwf.int/en/newsletter/166/news/forecast-performance-2020) and will be getting better, but it can only get so good. Even if we build the perfect weather model and feed it with the perfect initial and boundary conditions (practically impossible at the moment), the forecasts will still be overshadowed by chaos and/or ...


1

A popular website (let us not give any names) may have a a) computer generated forecast. b) computer generated forecast interpreted by a man (meteorologist specialized in short-term or long-term forecasts). In either case, "20% chance of rain" for a particular location is simply the full rain probability for a "prognosis area" times a ...


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