Maximum Number of Zones

[HereComesTheRain]

Congrats with this important step!

No, there is no need to connect GND next to N1.  The circuit "starts" on the +5V, then via a resistor, the optocoupler led and the red external led it connects to pin N1..8. Then the shift register IC pulls the pin (N1..8) low which essentially is GND. So the led will turn on.

The secondary power supply can now be connected to GND and JDC-VCC. Don't forget to remove the jumper!
Once connected the relays should make the sound you are waiting for a long time :-)

--Gerard

Removed the GND(s) from the RELAY MODULES connected to Pi POWER RAIL ground ( - )

Connected the GND and JDC-VCC to the secondary power supply POWER RAIL.

Did a RUN ONCE test LED(s) energized and the RELAY(s) made the nice "plock" sound.  HIP HIP HOORAY!!!!

Any idea how many mA the optocoupler (VCC) will draw for each of the active RELAYS?  I am trying to figure how many irrigation zones I can run at the same time without damaging the Pi.

I found the following on the website where I purchased the RELAYS: "5V 8-Channel Relay interface board, each one needs 15-20mA Driver Current; Equiped with high-current relay, AC250V 10A ; DC30V 10A"

Does DRIVER CURRENT refer to the power needed for the RELAY (JD-VCC) or the optocoupler (VCC) or is it the combination?

I really appreciate the time you have spent helping me with this.

T H A N K S  A G A I N ! ! !