Optimized biomimetic hair sensor arrays for sensing oscillating air flows

Artificial hair sensor arrays are bio-inspired from flow-sensitive filiform hairs of the crickets, one of nature’s best in sensing small air flows. The presented hair sensor arrays aim to realize higher sensitivities compared to our previous sensor arrays by means of model-based design optimizations and fabricated with advanced MEMS technologies. The artificial hair-sensor arrays display a clear figure-of-eight response and show remarkable sensitivities to oscillating air flows down to 0.85 mm/s surpassing noise levels even at 1 kHz operational bandwidths

MEMS Technology for Space Applications

Micro-technology enables the manufacturing of all kinds of components for miniature systems or micro-systems, such as sensors, pumps, valves, and channels. The integration of these components into a micro-electro-mechanical system (MEMS) drastically decreases the total system volume and mass. These properties, combined with the increasing need for monitoring and control of small flows in (bio)chemical experiments, makes MEMS attractive for space applications. The level of integration and applied technology depends on the product demands and the market. The ultimate integration is process integration, which results in a one-chip system. An example of process integration is a dosing system of pump, flow sensor, micromixer, and hybrid feedback electronics to regulate the flow. However, for many applications, a hybrid integration of components is sufficient and offers the advantages of design flexibility and even the exchange of components in the case of a modular set up. Currently, we are working on hybrid integration of all kinds of sensors (physical and chemical) and flow system modules towards a modular system; the micro total analysis system (micro TAS). The substrate contains electrical connections as in a printed circuit board (PCB) as well as fluid channels for a circuit channel board (CCB) which, when integrated, form a mixed circuit board (MCB)

Spontaneous mechanical oscillation of a DC driven single crystal

There is a large interest to decrease the size of mechanical oscillators since this can lead to miniaturization of timing and frequency referencing devices, but also because of the potential of small mechanical oscillators as extremely sensitive sensors. Here we show that a single crystal silicon resonator structure spontaneously starts to oscillate when driven by a constant direct current (DC). The mechanical oscillation is sustained by an electrothermomechanical feedback effect in a nanobeam, which operates as a mechanical displacement amplifier. The displacement of the resonator mass is amplified, because it modulates the resistive heating power in the nanobeam via the piezoresistive effect, which results in a temperature variation that causes a thermal expansion feedback-force from the nanobeam on the resonator mass. This self-amplification effect can occur in almost any conducting material, but is particularly effective when the current density and mechanical stress are concentrated in beams of nano-scale dimensions

Application of a microflown as a low-cost level-sensor

In this paper we present a novel `spirit level' sensor derived from a well known thermal flow sensor. The operation principle is based on the temperature difference of two identical heaters, caused by buoyancy of air. Heating as well as temperature sensing of the structures is carried out using temperature-dependent platinum resistors. Due to its simplicity the sensor is easily fabricated in silicon micro-machining technology. The theory describing the sensor is presented. The first experiments, using dc signals only, show adequate sensitivity, although high-accuracy operation is hampered by thermal drift