Thanks for your inquiry !
I am working on two HW solutions:
One is based on nRF52 Ble 5.0 with a minimal power consumption: a 200 mAh battery should last for more than one year.This solutions mainly intended for smartphone connections.
Another with a LoRa transeiver and a ATMmega328p to connect SmartSolenoid to a remote (up to 1000mt) Esp32 OpenSprinkler controller. Power consumption will be higher : a 2000mAh battery will be necessary for 4 6 month operations. In this case, a solar rechargeable battery will be probably the best solution .
The 2 different hw boards will fit in the same enclosure and will drive same solenoid coil.
Very soon I will make HW schematics and SW available on GitHub.,..