Sprinkler Switch

Reading up on evaporation in suburban soils versus transpiration rates in turf grass made me realize - this ain't as simple as checking a rain meter!

I've updated SprinklerSwitch to take in a huge number of additional values from NOAA, from which we now calculate two different "facts" for consideration when determining if we should irrigate the lawn or not:

1. If rain is likely to occur tomorrow, or

2. If the soil evaporation rate is likely to be lower than the amount of rain precipitated

Possible future precipitation is based on threshold values for precipitable water and cloud water, while evaporation is calculated based on specific humidity, ground temperature, and wind speed. A "turf nerf" percentage is applied to the evaporation rate to determine how quickly moisture would leave the lawn given complete turf grass coverage.

So far things are working! In my tests I'm seeing the irrigation system being correctly shut down when rains arrive. More testing is needed, but I've pushed these changes out as the latest release.

The latest version of the SprinklerSwitch is out - this is installable on the most recent Raspian images and automatically enables/disables irrigation based on rain forecasts.

Bear in mind there is no UI at the moment - this is all done using background tasks with a simple Node.JS script. Additional integrations for remote management are coming...

It has been a while since this project has been updated, so I've started a rewrite in Node.JS and provided a simpler installation path. The goal is to not build a web interface this time - but instead make this much more of an IoT sensor with potential API integration using SQSGateway.

An early version is posted in GitHub, with installation scripts and additional tweaks coming soon.

The SprinklerSwitch project has FINALLY been updated to support the latest version of Raspian. The biggest hiccup was switching to the WiringPi2 library - which is now the defacto library for addressing GPIO pins. The good thing is pin addressing is now entirely in userspace (no sudo required!), however there were significant changes that required refactoring.

Things are up & tested with the latest version of Raspian however - so have at it!