How to Catch a Monsoon

March 1, 2007

Duke undergraduates in the biomedical engineering capstone course "Design for the Developing World" tested devices they designed and built to catch monsoon rainwater. The devices, each built with no more than $20 worth of parts from The Home Depot, were tested Feb. 15 with simulated monsoon rains delivered by fire hose on the Engineering Quadrangle.

“In some parts of the world, if a family cannot collect monsoon rains, they won’t have enough water for their cattle, or maybe not even enough water to drink to stay alive themselves,” said BME Professor of the Practice Robert Malkin, who teaches the capstone design course.

“In addition, this project focuses the students on the cultural gap,” he continued. “In this class, students must try to understand a customer that is far away, both physically and culturally. This project starts them thinking about how different the world can be.”

Malkin said the monsoon challenge is a particularly good one for introducing students to the design process and the importance of building and testing prototypes.

While Malkin said he expected some of the collection devices might fail, all six managed to withstand a one-minute pounding from the falling water. The winning team captured 13 inches of water in a plastic bin. Two other teams, each collecting 11 inches, tied for second and third places.

The collection device devised by a team including Josh Ashley and Scott Liddle represented the most popular type: thin plastic sheeting with a hole at the center stretched across a wooden support structure.

“We went for a strong structure rather than a big area,” Ashley said of his design prior to the test. “If it breaks, it can be fixed. It’s serviceable.”

In the end, his prescription for success didn’t pan out, however. It was a similar collection device having a greater surface area of plastic sheeting and spindlier supports that ultimately performed the best.

Perhaps the most aesthetically pleasing design belonged to Elan Bresslour’s team. Their rain-catcher consisted of two pieces of blue tarp oriented in a wide V. The water was meant to slide down either tarp, falling into the plastic bin between them.

“We tried to use the plastic sheeting, but it is so thin,” Bresslour said. “We decided to go for a lesser size that would be more stable. But we had to spend half of our budget on the tarps alone.”

Bresslour’s group completed the test in a tie for second place after suffering a setback. Midway through their test, the wind blew the “rain” away from their water-catching contraption.

The monsoon devices are one of three projects students in the course will complete throughout the semester.

Students in the design class earlier built baby warmers constructed from light bulbs, which are slated for distribution in developing world hospitals in May, Malkin said.

Students will also work in teams on other medical devices later this semester, tackling projects that include an infant incubator that runs on a car battery, a surgical aspirator made from a truck fuel pump and an infant scale that can detect malnutrition in a refugee camp.

The class is part of the larger efforts of the organization Engineering World Health, of which Malkin is a founder. The Duke-Engineering World Health Summer Institute places engineering students in some of the world’s poorest hospitals in Tanzania, Honduras, El Salvador and other countries. Students fix equipment, install new equipment, train the staff in the use of their equipment, and identify projects for the following year’s Design for the Developing World class. In 2007, about 50 students from many universities will be participating in the Duke-Engineering World Health Summer Institute. Learn more at