Halarm
Simple domotic sensors notification system
A very simple sensors monitor system that rely on a low-cost wifi microchip connected to your home rooter (no external services involved) for the server, and your favorite device (PC, mobile, etc) for the client.
It uses raw TCP protocol (with no security), with tiny band consumption.
To handle ISP dynamic IP assignment, an effective No-IP free client has been implemented and included as a library, see: https://sourceforge.net/projects/arduinoip/