Exploiting ultra-low-power ultrasonic wake-up triggering for sensor nodes distance measurements

Most of today’s IoT-based computing systems offer an opportunity to build smarter systems for application areas such as healthcare monitoring and wireless sensor nodes. Since these systems are energy limited and remain idle for most of the time, they suffer from large leakage power dissipation. Another problem faced by such computing systems is sporadic power failures when employed with energy harvesters where the system loses its current state and needs long reinitialization time. To address these problems, this work combines asynchronous design techniques with nonvolatility to achieve ultra-low power operation during active mode and data retention during power failure. This paper first presents a detailed analysis of different implementations of volatile c-element and compares their performance in terms of power and delay. Then one of the implementations is selected for nonvolatile design of a hybrid c-element using emerging spin transfer torque–magnetic tunnel junction (STT–MTJ) technology which allows energy-efficient data retention during idle mode/power-off mode and during sudden power failures. Using this hybrid c-element, we design a novel nonvolatile weak conditioned half-buffer. The extensive analysis of these designs with different design metrics is performed at the circuit level using Synopsys HSPICE circuit simulator.

Get full-text (via PubEx)

A Model-Based Approach for the Design of Ultra-Low Power Wireless Sensor Nodes

2018 16th IEEE International New Circuits and Systems Conference (NEWCAS) ◽

10.1109/newcas.2018.8585492 ◽

2018 ◽

Author(s):

Oussama Brini ◽

Dominic Deslandes ◽

Frederic Nabki

Keyword(s):

Low Power ◽

Sensor Nodes ◽

Wireless Sensor ◽

Wireless Sensor Nodes ◽

Ultra Low Power ◽

Model Based

Get full-text (via PubEx)

High precision hybrid RF and ultrasonic chirp-based ranging for low-power IoT nodes

EURASIP Journal on Wireless Communications and Networking ◽

10.1186/s13638-020-01795-1 ◽

2020 ◽

Vol 2020 (1) ◽

Author(s):

Bert Cox ◽

Liesbet Van der Perre ◽

Stijn Wielandt ◽

Geoffrey Ottoy ◽

Lieven De Strycker

Keyword(s):

Power Consumption ◽

Low Power ◽

Pulse Compression ◽

Operation Time ◽

Distance Measurements ◽

Power Cost ◽

Ultra Low Power ◽

Positioning Systems ◽

Rf Systems ◽

Processing Power

Abstract Hybrid acoustic-RF systems offer excellent ranging accuracy, yet they typically come at a power consumption that is too high to meet the energy constraints of mobile IoT nodes. We combine pulse compression and synchronized wake-ups to achieve a ranging solution that limits the active time of the nodes to 1 ms. Hence, an ultra low-power consumption of 9.015 µW for a single measurement is achieved. The operation time is estimated on 8.5 years on a CR2032 coin cell battery at a 1 Hz update rate, which is over 250 times larger than state-of-the-art RF-based positioning systems. Measurements based on a proof-of-concept hardware platform show median distance error values below 10 cm. Both simulations and measurements demonstrate that the accuracy is reduced at low signal-to-noise ratios and when reflections occur. We introduce three methods that enhance the distance measurements at a low extra processing power cost. Hence, we validate in realistic environments that the centimeter accuracy can be obtained within the energy budget of mobile devices and IoT nodes. The proposed hybrid signal ranging system can be extended to perform accurate, low-power indoor positioning.

Get full-text (via PubEx)