XyMon, formerly known as Hobbit, is an open source monitoring application, which is available at http://www.xymon.com
The XyMon Monitor vibrates on status changes. You can choose, if you want to update only if you are connected via a WiFi network. A widget is available.
Self signed SSL certificates are supported.
The sourcecode of this app is available at https://github.com/ToBeHH/XymonMonitor