The London School of Hygiene and Tropical Medicine (LSHTM) is employing a real-time location system (RTLS) to gain an understanding of hygiene practices within the homes of Londoners, and plans to then use the technology in developing nations to help learn how to prevent communicable diseases—including diarrhea. The system is designed to create a record of individuals’ bathroom and kitchen practices, in order to determine when and how often hand washing occurs, and whether there is a risk of contamination—for example, when handling food immediately after flushing a toilet.
To track these activities, the researchers intend to install an RTLS provided by Visonic Technologies (VT), consisting of active RFID tags, low-frequency (LF) exciters and receivers. Washington State University‘s CASAS Smart Home Project (which focuses on creating smart home technology) is providing the software that serves as an interface between Visonic’s solution and the LSHTM database, where the culled data can be evaluated.
Research is being overseen by Robert Aunger, a senior researcher at LSHTM. The researchers were challenged with finding a way to observe health practices within the home. Simply asking participants to fill out questionnaires is insufficient, he says, since the research team would have to rely solely on each individual’s truthfulness and accuracy regarding his or her personal habits, thereby resulting in data that may not be reliable. Having a researcher follow a particular participant and watch that person’s behavior is also unlikely to yield typical results, he notes. Instead, the group hopes to let technology do the work, by constantly tracking behavior patterns over a period of months, in such a way that the users would become accustomed to the technology and fall into their usual habits. Aunger says he sought a system that could retrieve large amounts of information about users’ home hygiene habits. To that end, he began looking into RTLS technology, and came across Visonic’s solution. “I realized there were robust systems already out there,” he states. “We’re not engineers, so [having an existing system to use] makes it much easier.”
The system consists of active 433 MHz RFID tags attached to wristbands that transmit a unique ID number linked to information pertaining to the individual wearing a specific wristband, while 125 kHz LF exciters are attached to walls or other surfaces near commonly used items, such as toilet flush handles, soap dispensers, tooth brushes, dental floss, kitchen towels and refrigerator handles. Receivers then capture data about each incident in which a tag came within range of an exciter—up to 1.5 meters (4.9 feet)—thus indicating where the tag was located, by transmitting its own ID, as well as that of the specific exciter within its range.
The solution was first tested at the home of one of the London researchers. In January 2011, the group intends to provide the solution to 75 households, with two volunteers from each home participating in the study.
The initial testing consisted of a single receiver and several exciters—battery-powered LF transmitters measuring 3 centimeters (1.2 inches) in diameter—placed at locations within the researcher’s bathroom and kitchen. The wristband beacons every 10 seconds upon detecting that it is in motion, based on an indication from the tag’s built-in accelerometer. When the tag comes within 10 centimeters to 30 centimeters (3.9 inches to 11.8 inches) of the exciter, it receives that exciter’s signal and begins transmitting four times per second, with its own ID number and battery status, as well as the ID of the exciter from which it is receiving transmission.
The badge’s signals are received by a Visonic reader located up to 1.5 meters away, though the interrogator can read tags from a distance of up to 50 meters (164 feet) or more. The reader captures the data and routes it to a GlobalScale Technologies GuruPlug (a compact, low-power Linux-based computer). The plug computer stores the information and transmits it via an Internet connection to LSHTM, which uses the CASAS gateway interface to help discern the data’s meaning, including the behaviors that have occurred, and in what order.
In January 2012, the 75 London families will each be asked to take a kit home that will include several LF exciters, two wristbands, multiple object tags, one receiver and a GuruPlug server. The system will track every activity in which the wristband comes within range of an exciter, and will forward that data to LSHTM for interpretation. Each household will be monitored by the school for approximately 18 months, in order to determine how well new hygiene habits—such as tooth-brushing, flossing and medicine adherence—are being maintained.
Based on the results of the study with the 150 London participants, LSHTM may then determine whether the system can be deployed in developing nations, in order to study methods for reducing the rate of infectious disease contamination.