Wireless biomedical signal monitoring device on wheelchair using noncontact electro-mechanical film sensor.

The present study purposed to measure the BCG (Ballistocardiogram) of subjects on a wheelchair using a noncontact electro-mechanical film sensor (EMFi sensor) and detect the respiratory rate from BCG in real-time while the subjects are moving. In order to measure wirelessly the BCG of subjects moving on a wheelchair, we made a seat-type noncontact EMFi sensor and developed a transmitter and a receiver using Zigbee wireless RF communication technology. The sensor is embedded with a 3-axis accelerometer to remove the noise of wheelchair vibration from BCG signal. Signal obtained from each sensor goes through the A/D converter and is recorded in the SD (Secure Digital) card in PDA (Personal Digital Assistance) with a receiving part. We also developed a PC (Personal Computer) data analysis program, analyzed data recorded in the SD card using the program, and presented the results in graph. Lastly, this study demonstrated that a warning message can be sent from PDA to the remote server via a CDMA (Code Division Multiple Access) network in case the person on wheelchair falls in emergency. Our experiment was carried out with healthy male and female adults in their 20s who volunteered to help this research. The results of analyzing collected data will show that the respiratory rate can be measured in real-time on a moving wheelchair.