So I am stoked about the new version 3.0 capability to upgrade firmware over the network, it was really the only thing that was lacking in previous version. my question is this, i was just reading the install guide for the 3.0 which i haven’t ordered yet (this will be by 3rd open sprinkler purchase) and i noticed that the expansion board has somehow also been upgraded and will no longer work for the new version. maybe i read that wrong. can someone confirm and is there a work around to using the older expansion boards with 3.0? i can swallow 150 for the new controller but having to drop 50 each for the expansion boards again is hanging me up. is it simply a molex connection that has changed? can it be required to work still? what do i do? is there a firmware upgrade for 2.3 that allows for remote firmware upgrades? thats really all i want to be able to accomplish as the device works perfectly, just unplugging it all and moving it inside my office and hooking up to a computer is cumbersome.
You are correct that OpenSprinkler 3.0 only works with expander version 3.0 — this expander and the previous (2.1) use completely different connectors and pins, so they are not compatible.
More technically, expander 3.0 uses I2C IO expander chips, while previous version uses a simple shift register. This changes was done for a variety of reasons: the I2C IO expander chip uses much fewer pins, is easy for the microcontroller to enumerate directly (previously the enumeration has to be done through an analog pin, and the ESP8266 WiFi chip only has 1 analog pin already reserved for current sensing), and it can output higher current, which helps to turn triac fully on (whereas the shift register’s output current is much more limited). In any case, for these reasons, the hardware was completely changed.
If you’ve bought previous versions of OpenSprinkler, and considering upgrade, you can contact us and we may be able to offer some discounts so that you don’t have to pay full price for the controller and expanders.