After several weeks of hard work, I am excited to announce that OpenSprinkler v1.1 is now available!
So what’s new in this version? The biggest improved feature is hardware support for arbitrary (>8) number of stations through extension boards. This was actually quite easy to implement: the main hardware change is added pinouts for the 74HC595 shift register, which allows cascading additional shift registers to expand the number of stations. The latest software has also been updated to generically support any number of stations. So this leads to a very economic way to expand the number of stations, which is often very expensive with commercial sprinkler timers.
Another change is that the station terminals now use a common wire + individual station wire design, compatible with commercial sprinkler timers.
Other minor changes include an added 750mA fuse for current protection, and added RTC pinouts to support external I2C RTC breakout board.
Check detailed Release Notes here. The kit is now available in my hobby shop. You can get it either as a DIY kit, or a fully assembled and tested product. Detailed assembly instructions can be found here.