Have you ever been away from your house and wanted to know if your doorbell has been rung? Do you not have a doorbell and don't want to rewire your house? This is for you!
For this project you will need a Particle Photon and an IFTTT account. In the IFTTT page select new applet. Choose Particle for the "if" part, "monitor an event" and fill in the names. Event name is "doorbell" and "is if" is "HIGH". Choose your Particle Photon you're using and move to the next step. In the "then" section choose phone call and set it to call your number with any message you want. Set it to on and you're done! Now just flash your Photon with the included code and wire it together.
Connect everything together as it is shown in the schematic. If you want, you can get a battery pack that outputs 3.7 to 5v and hook it up to the Photon inside of the 3D-printable enclosure.
This project is a good and cheap replacement for the "Ring" doorbell, saving you about $150! I included 4 mounting points if you wish to keep it on the outside of your house.