LIGA fabricated 19-element threshold accelerometer array

McNamara, Shamus; Gianchandani, Yogesh B.

doi:10.1016/j.sna.2003.10.064

Cited by 28 publications

(28 citation statements)

References 9 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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“…This advantage also lends itself to a better interface between electronic circuits or RF transmitters that can send information to a RF reader regarding the state of the accelerometer. This has been demonstrated previously utilizing surface micromachining techniques with materials other than carbon nanotubes such as plastic, nickel, or silicon dioxide as shown by Todd et al (2008), Loke et al (1991), and McNamara and Gianchandani (2004). …”

Section: Discussionmentioning

confidence: 68%

Power-free bistable threshold accelerometer made from a carbon nanotube framework

Tanner

Jensen

2013

Mech. Sci.

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Abstract. This paper presents a design and a method for fabricating and testing fully compliant, bistable threshold accelerometers made from a carbon-infiltrated carbon nanotube framework. Two different configurations based on differences in compliant beam angles are presented. Both configurations were tested under constant accelerations produced by mounting them on a spinning disk and under impulse accelerations by mounting them to the end of a swinging pendulum with a stop at the lowest point of the pendulum path. Tests were also performed to observe the potential effects of stress relaxation in the carbon nanotube material. This was done by placing the accelerometers in their second stable position (nonfabricated position) and then testing them after a period of 24 h. Results show that in eight of the twelve tests there was no significant change due to stress relaxation. In the other four tests, the change was relatively small, especially when compared to stress relaxation effects in other materials such as plastics. Measurements indicate that the accelerometers show very high repeatability individually. However, we also observed that there is significant variation in switching acceleration between accelerometers with identical geometric parameters. This may be due to random variation occurring during the fabrication process.

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“…Acceleration switches were one of the earliest MEMS devices [3]. There has been periodic research on MEMS acceleration switches of various types throughout the last 30 years, but every type/configuration has been a single axis sensor (e.g., [4][5][6][7] among several others).…”

Section: Introductionmentioning

confidence: 99%

3-Axis acceleration switch for traumatic brain injury early warning

Currano

Becker

Smith

et al. 2012

2012 IEEE 25th International Conference on Micro Electro Mechanical Systems (MEMS)

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This paper reports on the design, fabrication, and testing of a 3-axis acceleration switch intended to serve as an early warning for traumatic brain injury (TBI). Mild TBI (colloquially termed "concussion") resulting from rapid acceleration of the skull has been rising in the public consciousness with recently increasing awareness of the dangers and long-term health risks associated with it. The sensor described here is an array of acceleration switches designed to cover the range of acceleration associated with TBI, and to do so with no external power draw until an acceleration event within this range occurs.

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LIGA fabricated 19-element threshold accelerometer array

Cited by 28 publications

References 9 publications

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

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

Power-free bistable threshold accelerometer made from a carbon nanotube framework

3-Axis acceleration switch for traumatic brain injury early warning

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