Outcome

The youtube video below shows the light controlled humidifier in action. When I shine light on the humidifier, the servo motor turns the knob off. When I remove the light, the LED lights up and the servo motor turns the knob on. When the humidifier is turned off, data is logged in a Google sheet through IFTTT. Unfortunately, I do not have a feature to constrain the servo motor. The video shows me holding the motor. The next step in this project would be to build a support for the servo so the device can ultimately run on its own.