For….anybody interested!
HARDWARE for OpenSprinkler with ESP8266.
The code is compatible for several different hardware configurations:
MCU: ESP8266 or ARDUINO MEGA
VALVE CONTROL: SHIFT REGISTER (like 74HC575 …. ) or I2C EXPANDER (like PCF8574)
RTC DS1307 or DS3231 breadbords with I2C epproms (like AT24C32 )
LCD LCD1602 or 2004 with parallel or I2C interface (or driven with a PCF8574)
BUTTONS on ANALOG or DIGITAL Inputs Lines (or trough a PCF8574).
So to start debugging it will be necessary to have at least one ESP8266 (better a NodeMCU v1.0 ) a RTC clock board (with EEPROM) and an LCD (better with I2c interface).
It will be good to have or a SHIFT register chip (like 74HC575) or a PCF8574 : leds can be used for debugging ,
later we can go with relay boards or with a simple Triac circuit.
Remember that voltage level for ESP8266 is 3.3V and this apply to all pin (5V is no good) better to verify that I2C components are 3.3V level compatibles…..
or to have a level shifter!
I am preparing a Fritzing project for components connection that can be done easily on a standard breadboard.