Just installed an OpenSprinkler using a Raspberry Pi and some board I picked up on eBay a year or so ago.
Super impressed thus far, especially with the iOS app. Thanks to everyone that has contributed.
My original thought, when I was going to try and write my own, was that it would be nice to allow actions via email. So basically if the weather forecast shows more than a 50% chance of rain, send me an email. In the email would be a button offering to “cancel” that day’s watering. There would be no login or anything required, the link has a unique GUID for that request and it allows for an easy way to cancel the schedule if my look outside differs from the actual weather forecast.
Sending notifications is fairly easy to do. Sending an email with a button that you can click to trigger an action is a bit more involved. As you said, you can generate a unique GUID and attach that to the email. This requires some bookkeeping of the GUID. It’s doable, but I would rather not want to make this a standard feature as I am not sure how many users would like this feature. You are certainly welcome to modify the firmware source code yourself to add such features.