My New IrrigationController

[marekd]

@karl261
Thanks,
in case I2C yes, and no.
with 1st generation [with 1 ProMini] I used I2C port expander PCF8574.
with 2nd generation [with MEGA2560] just pins, 8 pins, declared like this:

/**** Kepad settings /
const byte ROWS = 4;
const byte COLS = 4;
char keys[ROWS][COLS] = {
{'1', '2', '3', 'A'},
{'4', '5', '6', 'B'},
{'7', '8', '9', 'C'},
{'', '0', '#', 'D'}
};

byte rowPins[ROWS] = {47, 45, 43, 41};
byte colPins[COLS] = {39, 37, 35, 33};
int i2caddress = 0x20;
Keypad_I2C kpd = Keypad_I2C( makeKeymap(keys), rowPins, colPins, ROWS, COLS, i2caddress );

with 3rd generation - plan to have 2nd ProMini with PCF expander.

attached library I use.

0_1474294070076_Keypad_I2C.zip

and some pictures of generation 3, which is under construct :)

Power supply:

and control box with 2 ProMinis:

[karl261]

@marekd Thanks for the detailed reply. What the monster capacitor for in gen 3?

I plan to build my keypad with one pro mini and the PCF8574. Like your gen 1 & 3. How did / are you planning to wire the PCF8574? It seems rather straight forward according to this:

https://www.hackster.io/venkatesh_rao/i2c-keypad-73a012

Is this the wiring you are using? Or is it different?

Since I am building a battery keypad, I was also planning to use the interrupt line of the PCF8574.

[marekd]

@karl261
Capacitor is not so big ;) generally helps.
I my wiring there is no pull-up resistors at I2C lines. Rest is the same.