A Sub-A Ultrasonic Wake-Up Trigger with Addressing Capability for Wireless Sensor Nodes

Abstract

Wireless sensor nodes spend most of the time waiting either for sensed data or for packets to be routed to the sink. While on board, sensors can raise hardware interrupts to trigger the wake-up of the processor, incoming packets require the radio module to be turned on in order to be properly received and processed; thus, reducing the effectiveness of dynamic power management and exposing the node to unintended packets cause energy waste. The capability of triggering the wake-up of a node over the air would makes it possible to keep the entire network asleep and to wake up the nodes along a path to the sink whenever there is a packet to transmit. This paper presents an ultrasonic wake-up trigger for ultra-low-power wireless sensor nodes developed as a plug-in module for VirtualSense motes. The module supports a simple out-of-band addressing scheme to enable the selective wake-up of a target node. In addition, it makes it possible to exploit the propagation speed of ultrasonic signals to perform distance measurements. The paper outlines the design choices, reports the results of extensive measurements, and discusses the additional degrees of freedom introduced by ultrasonic triggering in the power-state diagram of VirtualSense.

Electromagnetic Bridge Energy Harvester Utilizing Bridge’s Vibrations and Ambient Wind for Wireless Sensor Node Application

“…Furthermore, due to the rapid developments in low power sensors, microcontrollers, conditioning circuits [6], power management circuits [7], and transmission module and because of efficient wireless sensor networks [8], the power requirement of WSNs is on a sharp decline. The energy harvesting technique [9][10][11][12][13] that is developed two decades ago has the tendency and capability to power these low power WSNs [14]. The energies, those are present in bridge's environment and can be taken into the account for energy harvesting, are vibration (vehicle-induced vibrations), acoustic (vehicle noise), wind (naturally blowing wind and air surges produced due to vehicle motion), and solar.…”

A Survey About Prediction-Based Data Reduction in Wireless Sensor Networks

“…Additionally to the predictions, [Lattanzi et al 2013;Bogliolo et al 2014] adopted a solution at hardware level (called wake-up receiver) to reduce the energy consumption during idle periods, improving the communication between sensor nodes. Simulation results showed that the combination of both mechanisms could lead to larger gains than adopting each technique in isolation.…”

Smartphone remote control for home automation applications based on acoustic wake-up receivers

“…It uses offthe-shelf ultrasonic transducers with which a wake-up distance up to 8.6 meter is achieved. Another paper presenting an ultrasonic wake-up receiver with less than 1 μW of energy operating at 40 kHz for wireless sensor networks can be found in [9].…”