We finally got the camera and solenoid valve circuits working! Above is a picture of the circuit we built and tested. I’ve already told you in a previous post how our old camera control circuit worked, and this one is pretty much the same. As for the solenoid valve circuit, here’s how it works:

A brown wire runs from the Raspberry Cobbler to the red wire on the other breadboard. This red wire is connected to a one kilo-ohm resistor. The resistor is connected to the base of an NPN transistor. The emitter of the NPN transistor is connected to ground. The collector of the NPN transistor is connected to one side of the coil in the black relay. The other side of the coil is connected to a twelve volt power source. The switch in the black relay is connected to the solenoid. It switches power to the solenoid. When power is switched to the solenoid, it will release water.

We solved the problem we were having with our transistor. There was too much current flowing through the transistor, so we used a relay to handle the high current of the solenoid.

We wrote the program to control the infrared shutter release and the solenoid valve in Python. Once all our circuits were hooked up, we ran the program, and it was successful!