Journal of the Institute of Electronics and Information Engineers (전자공학회논문지)

The Institute of Electronics and Information Engineers (대한전자공학회)
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A study on Detecting a Ghost-key using Additional Coating at the Membrane type Keyboard)

코팅 추가에 의한 멤브레인 키보드에서의 고스트-키 검출에 관한 연구

  • Lee, HyunChang (Dept. of Information and Telecommunication Engineering, Kongju National University) ;
  • Lee, MyungSeok (Electric-Power Conversion Control Engineering Design Team, Hyundai Motor Group)
  • 이현창 (국립 공주대학교 정보통신공학부) ;
  • 이명석 (현대자동차 전력변환제어설계팀)
  • Received : 2016.05.09
  • Accepted : 2016.06.29
  • Published : 2016.07.25
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Abstract

This paper presents a novel method for detecting a ghost key at the membrane type keyboard, which has additional resistive coating to the membrane film. Also, the optimal ratio of resistances for detecting a ghost key was designed based on the characteristics of the membrane film. The optimal ratio of resistances was considered to be able to detect the worst case (i.e., difference voltage between normal key and ghost key is minimum). The ability of the proposed methods are evaluated by simulation studies in this paper. In order to verify the proposed method, the experiment was carried out with a designed circuit and A/D (analog to digital) in MCU (micro controller unit). The proposed method is implemented into the membrane type keyboard and is verified by experimental results.

본 논문에서는 멤브레인 방식 키보드에서 고스트-키를 검출하는 새로운 방법을 제시하였다. 멤브레인 필름에 저항성 도체를 추가로 코팅하는 하드웨어적인 변경을 제시하고, 이때 발생하는 정상-키와 고스트-키에 대한 최적의 검출 저항비에 관해 이론적으로 분석하였다. 저항비는 검출전압 차가 가장 작은 최악의 키 조합에 최적인 비율을 적용하며, 시뮬레이션에 의해 다른 키 조합에 대해서도 이 비율을 적용해 고스트-키를 검출할 수 있음을 보였다. 제시한 방법의 타당성을 입증하기 위해 실험 회로를 구성하고 마이크로프로세서의 아날로그-디지털 변환기를 이용해 전압을 추출하였으며, 그 결과에 따르면 정상-키와 고스트-키 사이에 뚜렷한 전압차가 발생해 멤브레인 방식 키보드에서 발생하는 고스트-키를 확실하게 검출할 수 있음을 확인하였다.

Keywords

References

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