The OpenWSN project is an open-source implementation of a fully standards-based protocol stack for capillary networks, rooted in the new IEEE802.15.4e Time Synchronized Channel Hopping standard. IEEE802.15.4e, coupled with Internet of Things standards, such as 6LoWPAN, RPL and CoAP, enables ultra-low-power and highly reliable mesh networks, which are fully integrated into the Internet. The resulting protocol stack will be cornerstone to the upcoming machine-to-machine revolution.This article gives an overview of the protocol stack, as well as key integration details and the platforms and tools developed around it. The pure-C OpenWSN stack was ported to four off-the-shelf platforms representative of hardware currently used, from older 16-bit microcontroller to state-of-the-art 32-bit Cortex-M architectures. The tools developed around the low-power mesh networks include visualisation and debugging software, a simulator to mimic OpenWSN networks on a PC, and the environment needed to connect those networks to the Internet.Experimental results presented in this article include a network where motes operate at an average radio duty cycle well below 0.1% and an average current draw of 68 A on off-the-shelf hardware. These ultra-low-power requirements enable a range of applications, with motes perpetually powered by micro-scavenging devices. OpenWSN is, to the best of our knowledge, the first open-source implementation of the IEEE802.15.4e standard.

Time slotted channel hopping (TSCH) is the highly reliable and ultra-low power medium access control technology at the heart of the IEEE802.15.4e-2012 amendment to the IEEE802.15.4-2011 standard. TSCH networks are deterministic in nature; the actions that occur at each time slot are well known. This paper presents an energy consumption model of these networks, obtained by slot-based "step-by-step" modeling and experimental validation on real devices running the OpenWSN protocol stack. This model is applied to different network scenarios to understand the potential effects of several network optimization. The model shows the impact of keep-alive and advertisement loads and discusses network configuration choices.Presented results show average current in the order of 570 µA on OpenWSN hardware and duty cycles 1% in network relays in both real and simulated networks. Leaf nodes show 0.46% duty cycle with data rates close to 10 packets per minute. In addition, the model is used to analyze the impact on energy consumption and data rate by overprovisioning slots to compensate for the lossy nature of these networks.

Thousands of industrial gas leaks occur every year, with many leading to injuries, deaths, equipment damage, and a disastrous environmental effect. There have been many attempts at solving this problem, but with limited success. This paper proposes a wireless gas leak detection and localization solution.With a monitoring network of 20 wireless devices covering 200m 2 , 60 propane releases are performed. The detection and localization algorithms proposed here are applied to the collected concentration data, and the methodology is evaluated. A detection rate of 91% is achieved, with seven false alarms recorded over three days, and an average detection delay of 108 seconds. The localization results show an accuracy of 5 meters. Recommendations for future explosive gas sensor design are then presented.

Recent standardization efforts on Industrial low power wireless communication technologies clearly bet for the Time Slotted Channel Hopping (TSCH) medium access control layer as it proved to achieve 99.999% reliability while ensuring deterministic behavior. Standards such as WirelessHART, ISA100.11a and IEEE802.15.4e rooted at the TSCH MAC layer, are used to connect millions of Industrial devices today enabling the emergence of the Industrial Internet paradigm. At that point and due to the ultra-low energy profile of TSCH networks, scavengers come into play enabling autonomously powered control and monitoring systems on Industries. Yet, putting these systems together requires a clear understanding of their behavior. Therefore, this article presents a methodology and model to reliably dimension scavenger properties to network requirements and application needs, allowing Industries to optimize the adoption of that technologies while keeping technical risks low.Index Terms-Low-power modelling, industrial wireless, energy scavenging, self-powered wireless sensor networks.

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We demonstrate a low-cost, 21 x 12 mm prototype Stick-on Electricity Meter (SEM) PCB to replace traditional incircuit-breaker-panel current and voltage sensors for building submetering. A SEM sensor is installed on the external face of a circuit breaker to generate voltage and current signals at a 960 Hz sample rate. This allows for the computation of real and apparent power as well as capturing harmonics created by non-linear loads. The prototype sensor is built using commercially available components, resulting in a component cost of under $10 per SEM in moderate quantities. With no high-voltage install work requiring an electrician, this leads to an installed system cost that is roughly ten times lower than traditional submetering technology. Measurement results from lab characterization as well as a real-world residential dwelling installation are presented, verifying the operation of our proposed SEM sensor. The SEM sensor can resolve breaker power levels below 10W and consumes approximately 16 mA from a 5V supply.

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