I have two questions about your solenoids.
I'm creating a project to pull a string when a cat enters a door to cause the door to close behind her. The door is a standard screen door with a standard door closer. I want to prop the door open with a small stick, attach a string between it and one of your 9v solenoids. I'm building a circuit to activate the solenoid when the cat crosses a laser beam. I'm modifying the project shown here: http://www.youtube.com/watch?v=zQK1kTh57Fk
to activate the solenoid instead of a camera, as shown in the video. I also want to activate an audio alarm, so I know when the door has been closed.
My first question is which of your 9v solenoids do you recommend:
The small one at: http://www.adafruit.com/products/412
Or the larger one at: http://www.adafruit.com/products/413
My 2nd question is how do I need to modify the project in the video to work with your 9v solenoid?