WIRELESS SENSOR NODE WITH LOW-POWER SENSING

Wireless sensor network consists of a large number of simply sensor nodes that collect information from the external environment by sensors, process the information, and communicate with other neighboring nodes in the network. Usually sensor nodes operate with exhaustible batteries unattended. Since manual replacement or recharging the batteries is not an easy, desirable and always possible task, the power consumption becomes a very important issue in the development of these networks. The total power consumption of a node is a result of all steps of operation: sensing, data processing and radio transmission. In this work we focus on the impact of sensing hardware on the total power consumption of a sensor node. Firstly, we describe the structure of sensor node architecture, identify its key energy consumption sources, and introduce an energy model for the sensing subsystem as building block of a node. Secondly, with aim to reduce energy consumption of a node we propose implementation of two power-saving techniques: duty-cycling and power-gating. Duty-cycling is effective at system level. It is used for switching a node between active and sleep mode (with duty-cycle factor of 1% reduction of in dynamic energy consumption is achieved). Power-gating is implemented at circuit level with goal to decrease a power loss due to leakage current (in our design, a reduction of dynamic and static energy consumption of off-chip sensor elements as constituents of sensing hardware within a node of is achieved). Our MATLAB simulation results suggest that in total for a sensing hardware thanks to involving of duty-cycling and power-gating secures a three order of magnitude reduction ( ) in energy consumption can be achieved compared to a node architecture in which the implementation of  both energy saving techniques are omitted

Design of a ferrite rod antenna for harvesting energy from medium wave broadcast signals

Radio frequency (RF) energy harvesting is an emerging technology that has the potential to eliminate the need for batteries and reduce maintenance costs of sensing applications. The antenna is one of the critical components that determines its performance and while antenna design has been well researched for the purpose of communication, the design for RF energy harvesting applications has not been widely addressed. The authors present an optimised design for such an antenna for harvesting energy from medium wave broadcast transmissions. They derive and use a model for computing the optimal antenna configuration given application requirements on output voltage and power, material costs and physical dimensions. Design requirements for powering autonomous smart meters have been considered. The proposed approach was used to obtain the antenna configuration that is able to deliver 1 mW of power to 1 kΩ load at a distance of up to 9 km, sufficient to replace batteries on low-power sensing applications. Measurements using a prototype device have been used to verify the authors simulations

Signal Processing and Propagation for Aeroacoustic Sensor Networking,” Ch

Passive sensing of acoustic sources is attractive in many respects, including the relatively low signal bandwidth of sound waves, the loudness of most sources of interest, and the inherent difficulty of disguising or concealing emitted acoustic signals. The availability of inexpensive, low-power sensing and signal-processing hardware enables application of sophisticated real-time signal processing. Among th

Energy Harvesting - Wireless Sensor Networks for Indoors Applications Using IEEE 802.11

AbstractThe paper investigates the feasibility of using IEEE 802.11 in energy harvesting low-power sensing applications. The investigation is based on a prototype carbon dioxide sensor node that is powered by artificial indoors light. The wireless communication module of the sensor node is based on the RTX4100 module. RTX4100 incorporates a wireless protocol that duty-cycles the radio while being compatible with IEEE 802.11 access points. The presented experiments demonstrate sustainable operation but indicate a trade-off between the benefits of using IEEE 802.11 in energy harvesting applications and the energy-efficiency of the system

Evolution of Format Preserving Encryption on IoT Devices: FF1+

The Internet of Things (IoT) is a network of interconnected low-power sensing devices designed to interact and communicate with each other. To avoid compromising user privacy, it is necessary to encrypt these channels. We introduce Format Preserving Encryption (FPE), a modern cryptosystem that allows full customization of the ciphertext, while offering comparable security to AES. To gauge the performance of FPE, we compare the NIST-approved FF1 algorithm against several symmetric and asymmetric encryption schemes on a Raspberry Pi 3. While suitable for small plaintexts, FF1 breaks down for longer character strings. We propose a modified algorithm, FF1+, that implements dynamic round selection and key scheduling. Significant performance improvements are observed in our results, thus demonstrating FF1+ as a viable cryptosystem for IoT devices

Aerodynamic imaging by mosquitoes inspires a surface detector for autonomous flying vehicles

Some flying animals use active sensing to perceive and avoid obstacles. Nocturnal mosquitoes exhibit a behavioral response to divert away from surfaces when vision is unavailable, indicating a short-range, mechanosensory collision-avoidance mechanism. We suggest that this behavior is mediated by perceiving modulations of their self-induced airflow patterns as they enter a ground or wall effect. We used computational fluid dynamics simulations of low-altitude and near-wall flights based on in vivo high-speed kinematic measurements to quantify changes in the self-generated pressure and velocity cues at the sensitive mechanosensory antennae. We validated the principle that encoding aerodynamic information can enable collision avoidance by developing a quadcopter with a sensory system inspired by the mosquito. Such low-power sensing systems have major potential for future use in safer rotorcraft control systems