Floor warning system, 2010
Design a low-cost, self-sustaining system to monitor river levels, collect and transmit the measurements, and provide information in a way that can be used for analysis and visualization by the Red Cross.
During the Spring 2010 semester, my Major Studio Computation class participated in a group project to design a low-cost, self-sustaining system to monitor river levels, collect and transmit the measurements, and provide information in a way that can be used for analysis and visualization by the Red Cross.
Our solution is a modular measuring device that uses GSM networks to transmit water-level and location data via SMS to a central database. A small physical infrastructure with a large digital infrastructure.
My portion of the project was setting up a reliable way to transmit the river-level information from remote sites in Africa to be stored in a central database where the Red Cross, along with local officials, could analyze and propose solutions to known flooding problems. I used a combination of PHP, HTTP commands, and 3rd-party software (FrontlineSMS) to develop the solution.
The device consists of Sensor and Core. Sensor is comprised of 8 interlocking panels made of cement with a perforated top that contains a barometric pressure gauge; it is buried in the river bank, leaving the pressure gauge exposed to the open air. Core is a solar-powered microcontroller that receives the water-level readings from Sensor and transmits the data via SMS to a database.
At the outset, the entire class developed projects related to two issues presented to us by the Red Cross, which were well-water or river level measuring devices. The proposed location of these devices would be in remote sites in Africa.
After an initial mid-term critique with the Red Cross, six students continued the project specifically focused on measuring river-levels. We divided up the project into 6 definable deliverables, which were the physical device, the sensor, power, GSM modules, communicating/storing data, and visualizing the information collected. My portion of the project was communicating and storing the data.
Based on other NGO’s success with FrontlineSMS in similar types of projects in different areas in Africa, I used FrontlineSMS as the low-cost means of receiving GSM messages from the device and storing them to a database.
Through a good amount of research on forums, etc, I selected an unlocked Sierra Wireless 885 Aircard (also called Sierra Wireless USBConnect Mercury) as my modem of choice. I also purchased an AT&T “Pay-as-you-go” data plan SIM card (unlimited text and data, $0.25/minute calls) since I would only be using it for text messages.
I continued with setting up the FrontlineSMS system, and successfully set up a script that receives, parses, and saves the SMS messages to our database using HTTP commands calling to a PHP file on our server.