I'm designing a control circuit to operate a watering system. I've got a main inlet valve, four outlet valves, and soil moisture sensors in the mix, driven from a 25.4 V CT transformer. I was wondering if someone could review the schematic diagram. I have to make sure I didn't do anything outstandingly stupid, considering this is my first foray into controlling solenoids via MOSFETs / relays. Some explanation of the schematic is in order:
PIN1 is +12 VAC from the transformer
PIN2 is 0 VAC
PIN3 is -12 VAC
PIN1/PIN2 go to the main inlet valve, a 24 V solenoid valve.
The PIN1/PIN2 combinations across the top go to the outlet valves, all of which are 12 VDC solenoid valves.
The PIN1/PIN2 conbinations across the bottom go to the soil dampness sensors (simple soil moisture sensors made from plaster of paris and galvanized nails).
The data pins go to analog pins on the Arduino. Signal pins go to digital pins on the Arduino. The Arduino is powered from the V+/GND pins via its Vin pin.