This was a project for my boss that had troubles leaving the gate open at his house. (Especially because his girlfriend would give him the end of it!)
The server has a magnet swtich (reed) that detects if the gate is open or closed. If the gate has been opened for more than the configurable time it'll send a text message to 1 or more people. The client has a light indicator telling if the gate is open or closed.
