The flatness of the force sensitive EMFi sensors makes it possible to hide them under the upholstery of furniture without anybody noticing the sensors. In a seat like this these sensors can measure the mechanical movement of the heart, the ballistocardiogram (BCG).

The BCG is a less known method to analyse the condition of the heart than the electrocardiography (ECG). BCG was studied actively around 1940-1975 but the complicated equipment and the development of ECG analysis sidelined it. The availability of new sensors like EMFi gives new possibilities to manufacture BCG measurement devices inexpensively.

The built ProHeMon BCG chair measures two channels of BCG (from the seat and the back) and one channel of ECG with the copper electrodes attached to the hand rests. The signals are amplified and transmitted wirelessly to a nearby base station. The analysis software calculates the heart rate, breathing rate and various other parameters of the signals and presents them to the user. Studies have been made to classify the BCGs automatically to normal and abnormal classes but more data is still needed to the data libraries before the test cases are complete enough to allow reliable classification. Applications which require only the heart rate and breathing rate can already benefit the present version of the chair. The chair approach could also find applications in the home care of the elderly.

The authors hold a Utility Model Right (FI 6295, year 2004) to this chair invention. This study was conducted in co-operation with Tampere University Hospital, Department of Physiology.

Links
Emfit Ltd. EMFI sensors
Final report of the project
Cardiovascular System Dynamics Society

Designed by Alpo Värri 25.8.2008