This is a silly little project that combines an Alexa skill with a Particle Photon and a servo motor to push a door so it closes.
Firstly the door needs to be held open with a magnet with a light hold, this will allow it to be easily pushed closed. I did this by gluing a small neodymium magnet to the existing door stop, this mated with a metal plate from a normal magnetic door catch.
The servo connects directly to the Particle Photon and I have 3D printed a housing which sits against the door frame and holds the servo in place. The arm then moves down to push the door closed.
The code that runs on Alexa is very simple, in my case its a skill called study and there is an action called close door which calls the endpoint exposed by the Particle system.
I can then use the slightly clunky phrase
Alexa ask the study to close the door