Sensor Box and Sensor Photos
Inside the Sensor BoxSensor Box
Patio Photocell
Patio Photocell
Backyard Photocell
back Photocell
The spa heater here has a gas valve powered by AC. An Opto-isolator is connected to this circuit to monitor how ofter and how long the heater runs.
Spa heater		The photocell signals are filtered in the Secondary Box
Secordary Box