This is the source code of the IBM Bluemix IoT hackathon at IBM Germany Lab.
The hackathon took place on March 10 and March 11, which happens to be the 5 year anniversary of Japan 311 earthquake/tsunami. Inspired by that devastating disaster, we hooked up 4 Raspberry Pi's simulating 4 different homes within the same city. Each raspberry pi was assembled with multiple sensors such as accelerometer sensors, motion sensors, humidity/temperature sensors and raindrop sensors. When a single accelerometer sensor detects significant movements, all registered smart phones will get a warning text, if multiple accelerometer sensors detect movements in multiple homes, alarms on all raspberry pi's will be triggered to wake people up and buy them valuable 10 seconds or more. Since a Raspberry Pi is very cheap and affordable, we can build a similar solution in the real world before the country implements a national alert system.
For the video of this demo, see https://youtu.be/wpACAzNdkdE