Forschung Aktuell

 Science Service
Nr. 1, September 2000

TU Berlin Science Service of the TU Berlin
Nr. 1 / September 2000

Technology for senior citizens
Sensors to report falls in the home

Safety in the home is of crucial importance for the elderly. Scientists at the TU Berlin have developed a special personal alarm sensor which registers falls and automatically sends an alarm signal. This is to be integrated in a wrist-watch or ring and is expected to reach the markets in two years time.

Germans are getting older and older. Increased life expectancy means that over 25% of the population are now more than 60-years-old, and this figure seems set to rise to 35% by 2030. This development is also accompanied by a tendency towards early retirement, and the wish to live at home and remain independent for as long as possible.

Despite the increasing demand for special products to meet the needs of the elderly, there has been a slow response on the part of scientists and developmental engineers. But now German scientists from various disciplines have come together in a DFG-funded research project SENTHA (Seniors' Technology in the Home). Germany's research council DFG is investing more than 3 million German Marks in the seven sub-projects.

"The safety aspect is crucial for independence at home", explains Bert Schadow, an engineer at the Institute of Microtechnology and Medical Technology of the Technische Universität (TU) Berlin. In order to improve the safety of the old and infirm, the Berlin scientists working on the SENTHA project in cooperation with the BTU Cottbus have developed a personal alarm system which overcomes some of the deficits of currently available systems.

The person wearing one of the current systems will have to initiate the alarm signal, usually by pushing a button. But after a fall in the home, they will very often not be able to do this. The system being developed by the scientists of the TU Berlin will be able to register the emergency situation and automatically raise the alarm for medical assistance. It is also planned for the sensor to register on a continual basis important parameters such as pulse rate, rate of breathing, oxygen saturation, and mobility.

At first, the work in Berlin is concentrating on the automatic alarm system. Statistics show that 27% of all fatal accidents occur in the home, and of these about 80% are due to falls. A prototype of the automatic alarm system is already being tested. "We are using a sensor incorporating a mercury switch. The emergency alarm system sends out a signal if the main axis of the body remains at an angle of more than 45 degrees for thirty seconds or longer" is how Bert Schadow explains their alarm.

A similar device is already on the market in Finland. This system, costing US$ 2000, is currently being tested in Berlin. "In particular we would like to offer a better range, so the wearer can move safely over a wider area", said Schadow.

Medical parameters such as blood oxygen saturation or pulse rate can be registered by observing blood vessels with an infrared sensor. Such devices are already being used for medical monitoring in the form of ear-clips or carried on a finger.

However, a single medical parameter alone is not enough to be able to reliably assess the health status of elderly people. The important thing is to achieve the right combination which is appropriate for the user. Another key point is that the size and design of the emergency alarm system should not impede the wearer. For example, the functions could be integrated in a wrist-watch or ring, "It is important for us as engineers that the users find the alarm system acceptable" says Bert Schadow. The final product should be on the market within the next two years.


Contact: Bert Schadow, Technische Universität (TU) Berlin, Institute of Microtechnology and Medical Technology
Special field: Technology for the elderly
Research project: Safety and support functions in appliances for the old and infirm , sub-project of the Interdisciplinary Research Group "Seniors' Technology in the Home"
Address: Dovestrasse 6, 10587 Berlin, Germany. Tel.: +49 30 314-23388, E-mail:

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