Optimized design of a micromachined G-switch based on contactless configuration for health care applications

Ongkodjojo, Andojo; Tay, Francis Eng Hock

doi:10.1088/1742-6596/34/1/173

Cited by 40 publications

(32 citation statements)

References 11 publications

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“…Moreover, they can replace accelerometer systems for sensing and actuation with much less cost, since they have simpler structure and interface circuit, lower cost and less power consumption (Ongkodjojo and Tay 2006;McNamara and Gianchandani 2004). Taking the automotive airbag system as an example, merely an inertial micro-switch can achieve the same function as the complex system composed of three components: an accelerometer monitoring the car's acceleration, a decision/controller unit processing the acceleration signal, and a switch to fire the airbag when the acceleration exceeds a certain threshold due to impact (Younis et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Dynamic simulation of a contact-enhanced MEMS inertial switch in Simulink®

et al. 2011

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A novel contact-enhanced design of MEMS (micro-electro-mechanical system) inertial switch was proposed and modeled in Simulink Ò . The contact effect is improved by an easily realized modification on the traditional design, i.e. introducing a movable contact point between the movable electrode (proof mass) and the stationary electrode, therefore forming a dual mass-spring system. The focus of this paper is limited to a vertically driven unidirectional one for the purposes of demonstration, but this design concept and Simulink Ò model is universal for various kinds of inertial micro-switches. The dynamic simulation confirmed the contact-enhancing mechanism, showing that the switch-on time can be prolonged for the dynamic shock acceleration and the bouncing effect can be reduced for the quasi-static acceleration. The threshold acceleration of the inertial switch is determined by the proof mass-spring system's natural frequency. Since the inertial switches were fabricated by the multilayer electroplating technology, the proof mass thickness were assigned two values, 100 and 50 lm, in order to get threshold levels of 56 and 133 g respectively for the dynamic acceleration of half-sine wave with 1 ms duration. Other factors that influence the dynamic response, such as the squeeze film damping and the contact point-spring system's natural frequency were also discussed. The fabricated devices were characterized by the drop hammer experiment, and the results were in agreement with the simulation predictions. The switch-on time was prolonged to over 50 ls from the traditional design's 10 ls, and could reach as long as 120 ls. Finally, alternative device configurations of the contact-enhancing mechanism were presented, including a laterally driven bidirectional inertial switch and a multidirectional one.

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Section: Introductionmentioning

confidence: 99%

Dynamic simulation of a contact-enhanced MEMS inertial switch in Simulink®

et al. 2011

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“…Esquivel [7] analyzed the Casimir force in the micro-switch. Ongkodjojo et al [8] designed a micro-switch for health care applications. However, the microswitch could not precisely and reliably control the external circuit to switch.…”

Section: Introductionmentioning

confidence: 99%

Analysis of bistable inductive micro-switch based on surface micro size effect

Tian

Chen

2015

Applied Surface Science

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“…Inertial switches, also called acceleration switches or threshold accelerometers, are more suitable for these applications due to their simpler structures and interface circuits, lower costs, and less power consumptions [3], [4]. For example, they can be embedded in products, storage, and shipping containers to track and monitor mechanical shock and vibration during transportation and handling [4]; they can be incorporated on smart shirts to detect falls among elderly people for geriatric healthcare application [5]; they can be used in the side airbag system where a higher-speed response is needed than the frontal airbag system, eliminating the risk of misoperation by an electromagnetic noise [6], [7]. Since Frobenius et al reported an all-metal microcantilever array in 1972 [8], there have been plenty of publications on inertial microswitches, which have now become a major focus for research in recent years [9].…”

Section: Introductionmentioning

confidence: 99%

Development of a Novel MEMS Inertial Switch With a Compliant Stationary Electrode

Cai¹,

Yang²,

Ding³

et al. 2009

IEEE Sensors J.

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A novel microelecromechnical system (MEMS) inertial switch based on the surface micromachining technology was developed, which mainly consists of a proof mass as the movable electrode and a compliant stationary electrode above the proof mass, whose deformation during the contact process would enhance the contact effect and prolong the switch-on time. Based on the original design which had already realized the enhancing effect to some extent, the device structure was redesigned as a centrosymmetric structure with the stationary electrode changed from two bridge-type beams to one cross beam in order to reduce the off-axis sensitivity. More importantly, a contact point was installed on top of the proof mass, changing the effective contact area of the stationary electrode from its end to the center, which undergoes the largest deformation. Therefore, the contact effect would be improved further, which has been confirmed by the ANSYS transient simulation. This simulation combined with the Simulink dynamic simulation described the device behavior, which were in agreement with the drop hammer tests. The threshold acceleration of the redesigned inertial microswitch was around 70 g, and the tested switch-on time reached 30 s, more satisfactory than the original design.Index Terms-Compliant stationary electrode, inertial switch, microelecromechnical system (MEMS), surface micromachining technology, switch-on time.

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Optimized design of a micromachined G-switch based on contactless configuration for health care applications

Cited by 40 publications

References 11 publications

Dynamic simulation of a contact-enhanced MEMS inertial switch in Simulink®

Dynamic simulation of a contact-enhanced MEMS inertial switch in Simulink®

Analysis of bistable inductive micro-switch based on surface micro size effect

Development of a Novel MEMS Inertial Switch With a Compliant Stationary Electrode

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