I’ve searched around quite a bit for info on the SD card but I can’t seem to find answers.
Does the Opensprinkler 2.1u come with an SD card?
What type of SD cards are supported? What role does the SD card play? Is it required to power on and use the device or is it only there if you run out of space on the Atmega?
The current batch of OpenSprinkler does NOT come with microSD card pre-installed. The card is useful for storing logging data, and also for storing additional programs in the future. But it’s optional and the controller does not need it to run.