The solenoid valve that was chosen for this application is a 1" valve made by Lawn Genie. A picture of the valve is seen in Figure 1.
The solenoid is magnetic and is powered by 18 - 24 VAC. When the solenoid
receives 24 VAC, it is activated, the solenoid opens a path from one side
of the valve to the other. This caused the water to flow from the faucet
through the valve and to the hose connected to the sprinkler.
In order to turn the valve on and off a relay will be used. The coil
in this relay will be activated by a voltage of 5 VDC and will be rated
for at least 24 VAC. If the relay is activated, depends on the voltage
from the flip-flop. When the start button is hit, the relay will get the
voltage it needs to let the AC current to flow through it and open the
valve. When the stop button is hit, the photo eye detects the sprinkler,
or the timer gets to about an hour, the relay will not get the required
voltage and the valve will be shut.