Fast Fourier Transform (FFT) is an essential algorithm for numerous scientific and engineering applications. It is key to implement FFT in a high-performance and energy-efficient manner. In this paper, we leverage the properties of ultrasonic wave propagation in silicon for FFT computation. We introduce SonicFFT: A system architecture for ultrasonic-based FFT acceleration. To evaluate the benefits of SonicFFT, a compact-model based simulation framework that quantifies the performance and energy of an integrated system comprising of digital computing components interfaced with an ultrasonic FFT accelerator has been developed. We also present mapping strategies to compute 2D FFT utilizing the accelerator. Simulation results show that SonicFFT achieves a$2317\times$system-level energy-delay product benefits-a simultaneous$117.69\times$speedup and$19.69\times$energy reduction-versus state-of-the-art baseline all-digital configuration.

3-D-printed structures integrated with laser-cut spiral PZT bimorphs are used to obtain low mechanical resonance frequencies for energy harvesting and a vibration-activated mechanical switch. This structure is used to realize a batteryless vibration event detector and RF transmitter, using the energy in the vibration and a mechanical switch as a comparator. The low-resonance frequency of the 3-D-printed mechanical resonators is used to supply significant mechanical resonance gain and trigger the impulse response of the PZT bimorphs, resulting in an upconversion of resonance frequencies. RF pulses are generated by an LC resonator and transmitted by a loop antenna for reporting event detection. The 3-D-printed structure has resonances as low as 17.5 to 40 Hz corresponding to the vibration energy spectrum readily available in the environment. Theory and experiments to verify RF output are presented. At 40 Hz and 0.75 g excitation, the resulting RF pulse is at a carrier frequency of 10.9 MHz with energy extracted from the bimorph of 0.95 nJ per pulse. As a demonstration of the device, the wireless sensor node is used to identify operational modes of a portable gasoline electric generator.

Conventional two-dimensional structured illumination microscopy (SIM) requires 9 raw images to reconstruct a super-resolved image. In order to increase the frame rate of 2DSIM, attempts are being made to reduce the number of raw SIM images. However, all the proposed SIM reconstruction algorithms (SIM-RA) capable of reconstructing super-resolution (SR) image with a reduced number of raw SIM images operate in the spatial domain. Here, we present a frequency domain SIM-RA based on ordinary least squares technique, which enables reconstruction of SR image using 4 raw SIM images. Unlike the spatial domain RA, which produces the SR image through iterative convergence, the presented RA provides a single step solution. It also reveals the fundamental limitation of least number of raw images required for resolution doubling in SIM.

In this paper we present successful navigation of a mechanically linked insect moth-pair, using light-weight and low-power actuators, demonstrating insect powered micro air vehicles (MAVs). These MAVs can fly for long periods of time, consuming only a small fraction(1%) of power compared to purely mechanical MAVs. We demonstrate strategies for harnessing the high energy-density biofuel and high efficiency muscle actuators of insects using tissue-embedded and externally attached miniature insect generated momentum redirectors. Commercial off-the-shelf tail motor, a rudder that exploits flow behind the insect wings, and a steering mechanism that misaligns the thrust directions of two insects were all separately used to control yaw of the hawkmoth, Manduca Sexta, in tethered flight. Untethered flight control of two hawkmoths over 60 m was achieved using a 6 gm backpack, including a 3 gram helium balloon to keep the backpack airborne, for over 5 to 30 minutes of flight time.