The $1 Water Sensor
Dr. Woo Jin Chang, Associate Professor, Mechanical Engineering, has developed a menu of miniature electrochemical sensors that can detect—at low-cost and instantaneously—heavy metals, water acidity, and nutrients in drinking water and other fluids. Three Wisconsin companies have licensed the sensor and now Chang and his co-inventor are collaborating with a California-based company to commercialize it.
The thin, disposable sensors are the size of a small Band-Aid and cost a little more than $2 each. “My goal is to create a commercial sensor that costs users just $1,” he says. The price, he believes, would make the sensors affordable to more people, in addition to being more attractive to commercial companies.
Chang’s sensors can each detect one or more heavy metals at very low levels—including lead, arsenic, cadmium, mercury, chromium, and copper—and can determine the pH of water with a single drop. Water acidity must fall within a certain range to maintain the health of organisms that depend on it, he says.
The sensors (which use a screen-printed electrode with surface modification techniques, and an electrochemical sensing method) could benefit well owners and companies collecting water in the field.
Chang also is developing sensors that provide continuous monitoring of metals. The sensors could be integrated into existing water filtration-system equipment, or used to monitor natural waters such as rivers to immediately indicate the presence of chemical pollutants.
Tiny as they are, miniaturized sensors have scores of applications, including indicating blood-borne disease markers. Like the sensors that detect metals, the goal is to create a less invasive, quicker and cheaper identification methods, says Chang, who is researching this application.