Rain

 
*About:*
The rain project of the Department of Electronics, Communications, and Computer Engineering has been ongoing for almost six years. Annual undergraduate- and graduate-level project research on Philippine rainfall events have formulated rich problems and have contributed invaluable data and novel applications.

*Motivation:*
With an average of twenty typhoons entering the Philippine Area of Responsibility every year, rain-induced disasters such as landslides and flash floods are a constant risk to Filipino livelihood. In recent years, super-typhoons such as  Ondoy and Sendong have destroyed infrastructure and caused numerous casualties.

Such rain events, which are characteristic of tropical countries, present the need for methods of gathering rainfall information for disaster management. While satellite technologies are available, these cannot provide information about the spatial variations of tropical rain rates the way a high-density deployment of ground-based sensors can. Moreover, in countries like the Philippines, there should be dense deployment of traditional rain gauges enough to capture relevant data. Thus, there is a need for a complementary system of sensors that are low-cost, mobile, and can be deployed remotely.

*Hybrid sensor network:*
Early rain research used a hybrid network of sensors to gather rainfall information. A 4-km WiPAS link from the Ateneo de Manila to PLDT Balara was used as a backbone. Rain events cause attenuation in the link that is directly related to the rain rate across it. The hybrid network also used acoustic recorders as point sensors. The acoustic signal levels generated by rain drops on the sensor housing provide real-time spatial rain rate information.

*Current Developments:*
Currently, the rain project is using low-cost mobile devices based on the Android operating system as rainfall point sensors. These mobile devices run a software that records acoustic signal level and wireless received signal levels (GSM, WiFi, and 3G).  With the telemetric capabilities of the mobile devices, the data gathered are remotely accessible. The GSM functions and processing power of the devices also allow for SMS alarms to be sent when gathered data cause a trigger.

Furthermore, received signal levels from an estimated 700 subscribers of a 5 GHz broadband service are also are also being provided to the rain project by a major telecommunications service provider. These 700 data points act as a high-density, nationwide sensor network. The attenuations of the received signal levels during rain events are currently being mined for information.