European Journal of Applied Physiology

, Volume 105, Issue 3, pp 365–372 | Cite as

Helmet-based physiological signal monitoring system

  • Youn Sung Kim
  • Hyun Jae Baek
  • Jung Soo Kim
  • Haet Bit Lee
  • Jong Min Choi
  • Kwang Suk ParkEmail author
Original Article


A helmet-based system that was able to monitor the drowsiness of a soldier was developed. The helmet system monitored the electrocardiogram, electrooculogram and electroencephalogram (alpha waves) without constraints. Six dry electrodes were mounted at five locations on the helmet: both temporal sides, forehead region and upper and lower jaw strips. The electrodes were connected to an amplifier that transferred signals to a laptop computer via Bluetooth wireless communication. The system was validated by comparing the signal quality with conventional recording methods. Data were acquired from three healthy male volunteers for 12 min twice a day whilst they were sitting in a chair wearing the sensor-installed helmet. Experimental results showed that physiological signals for the helmet user were measured with acceptable quality without any intrusions on physical activities. The helmet system discriminated between the alert and drowsiness states by detecting blinking and heart rate variability (HRV) parameters extracted from ECG. Blinking duration and eye reopening time were increased during the sleepiness state compared to the alert state. Also, positive peak values of the sleepiness state were much higher, and the negative peaks were much lower than that of the alert state. The LF/HF ratio also decreased during drowsiness. This study shows the feasibility for using this helmet system: the subjects’ health status and mental states could be monitored without constraints whilst they were working.


Helmet Dry electrodes ECG EOG EEG Alpha wave Drowsiness 



This study was supported by a grant from the Advanced Biometric Research Center (ABRC) and the Korea Science and Engineering Foundation (KOSEF).


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Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Youn Sung Kim
    • 1
  • Hyun Jae Baek
    • 2
  • Jung Soo Kim
    • 1
  • Haet Bit Lee
    • 1
  • Jong Min Choi
    • 1
  • Kwang Suk Park
    • 3
    Email author
  1. 1.The Interdisciplinary Program in Medical and Biological Engineering, Graduate SchoolSeoul National UniversitySeoulRepublic of Korea
  2. 2.Graduate Program in BioengineeringSeoul National UniversitySeoulRepublic of Korea
  3. 3.Department of Biomedical Engineering, College of MedicineSeoul National UniversitySeoulRepublic of Korea

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