Denis Spirjakin

Combustible gases and early fire detection: an autonomous system for wireless sensor networks

Fires or toxic gas leakages may have grave consequences like significant pecuniary loss or even lead to human victims. In this paper we present an autonomous wireless sensor system for early fire and gas leak detection. The system consists of two modules: a gas sensor module and a power management module. The operation of the gas sensor module is based on the pyrolysis product detection which makes it possible to detect fire before inflammation. In addition, the on board gas sensor can identify the type of leaking gas. A generic energy scavenging module, able to handle both alternating current and direct current based ambient energy sources, provides the power supply for the gas sensor module. The harvested energy is stored in two energy buffers of different kind, and is delivered to the sensor node in accordance to an efficient energy supply switching algorithm. At the end of the paper we demonstrate the experimental results on gas detection, energy consumption evaluation, and show how to ensure the system autonomous operation.

Circuit Design and Power Consumption Analysis of Wireless Gas Sensor Nodes: One-Sensor Versus Two-Sensor Approach

Wireless sensor networks (WSNs) have recently been applied in industrial monitoring applications including hazardous gases detection. As a major power consumer of a node, gas sensors may significantly constrain its lifetime. Hence, the sensing circuit must be carefully designed to optimize performance and retain accuracy. In this paper, we propose for the first time the principle of gas concentration measurement based on a single sensor in a voltage divider circuit, instead of the well-known Wheatstone bridge sensing circuit, which employs two sensors. We discuss the design of a real WSN node for gas sensing and evaluate it with respect to an identical platform that uses the Wheatstone bridge. The proposed approach ensures significant energy savings and helps to avoid zero offset issue. Besides, we employ a more efficient and secure sensor heating profile; it does not damage the sensor and does not make gas sensing dependent on environmental conditions. Experimental results show a 30% reduction in power with respect to the state-of-the-art.

Compact Low Power Wireless Gas Sensor Node With Thermo Compensation for Ubiquitous Deployment

Wireless sensor networks (WSNs) have recently been applied for industrial monitoring, including combustible and flammable gases monitoring. In this work, we present a wireless gas sensor node in which a widely used Wheatstone sensing circuit based on two sensors is exchanged with a single sensor circuit, as well as the associate gas measurement procedure. The core of the measurement procedure is the four-stage heating profile, which enables low power consumption of sensing circuit and thermo compensation adjustment. A thermo compensation algorithm is capable of avoiding the effect of the environmental temperature on the measurements by keeping stable zero-offset within ±1 mV and ensuring low absolute error within 0.1% vol. The thorough design of the sensor node allows it to fit into the 5.5 cm3 packaging, which ensures its true ubiquitous deployment in outdoor and industrial environment.

Wireless multi-sensor gas platform for environmental monitoring

Air quality control is a monitoring task of high priority in the scope of Smart City and Smart Home applications. In fact, a number of sensors are required to successfully detect the leaks of various gases and their different concentrations. In this work, we present an autonomous multisensory wireless platform which includes both analog and digital gas sensors for environmental monitoring. The platform includes four measurement circuits with sensors of different types: one for analog catalytic/semiconductor gas sensor, two for analog electrochemical gas sensors and one for a gas sensor with digital data transmission interface. The platform ensures low power consumption and can operate either as a separate monitoring sensor node or as a part of wireless sensor network.

Design of smart dust sensor node for combustible gas leakage monitoring

In this work we present the results of design of smart dust sensor platform for combustible gas leakage monitoring. During the design process we took into account a lot of combustible gas sensor specific problems such as their huge power consumption, the necessity to work in explosive environment and sensor parameters degradation. To decrease power consumption we designed specific energy efficient algorithms for measurements. The resulting average power consumption of the node is low enough for one year autonomous lifetime. The methods and algorithms which was designed are very promissing for catalytic combustible gas sensors.

A wireless carbon monoxide sensor node with hybrid power supply

Gas monitoring is an important issue since the leakage associated with the penetration of gases in the surrounding environment can result in fatalities and harsh consequences. In this work, we propose a novel sensor node architecture for a wireless outdoor CO monitoring unit. To guarantee an autonomous operation, the sensor node is supported by a hybrid power supply, which takes advantage of both wind and solar ambient energy sources to power the node and to charge super capacitors that act as energy buffers. Also, the gas measurement logic is developed such that the energy consumption is minimized. An additional backup energy storage is based on a Li-ion battery. Using an electrochemical CO sensor, we secure the low power consumption of the node without degrading the sensing capabilities. Our solution can be applied for CO monitoring in urban areas and outdoor industrial facilities.

Internet connected wireless combustible gas monitoring system for apartment buildings

Despite the modern gas equipment, combustible gas leakage related emergency situations still take place and lead to building demolitions and human losses. Leak integrity failures because of anthropogenic and natural factors make impossible to prevent such emergency in other ways except providing continuous monitoring of combustible gas concentration and notification for people and special services. In this work, the design results of the Internet connected wireless sensor network for combustible gas concentration monitoring in apartment buildings is presented. The system consists of wireless autonomous gas sensors, actuators, routers and a gateway and its connected to a web service where it posts its data and gets events to react them in WSN.

A Multisource Energy Harvesting Platform for Wireless Methane Sensor

Sensors used for detecting combustible gases consume significant amounts of power. Energy management for these sensors can become an important issue when they are used as part of a wireless sensor network. This is because of the fact that wireless sensors are usually powered by batteries. Batteries have a finite lifetime and their replacement can take a considerable amount of time in a gas monitoring application where thousands of sensor nodes are deployed to measure the concentration of flammable gases. Moreover, the battery replacement procedure can turn into a more complicated task if the gas monitoring network is located in a harsh environment. Energy harvesting is a method which can increase the operation time of wireless gas sensor networks. In this article, we present a multisource harvesting circuit for a wireless gas sensor node. As for ambient sources, we have chosen solar and wind energy. Energy from ambient sources is stored in supercapacitors which have a capacity of 400 F. We prove that a catalytic gas sensor can operate for 2 days without batteries by using the developed scheme.

Energy harvesting algorithms for wireless multi-sensor gas platform

Air quality control is a monitoring task of high priority in the scope of Smart City and Smart Home applications. In fact, a number of sensors are required to successfully detect the leaks of various gases and their different concentrations. Using wireless sensor platform for these purpose its necessary to think a lot about appropriate power sources and power management. In this work, we present autonomous multi-sensor wireless platform power supply algorithms. The platform uses alternative power sources (solar panel and wind generator) as main power supply and lithium battery as reserve one. These power supply components are managed to maintain the most efficient using of power sources during whole working cycle.

Uniform inbuilt wireless sensor node for working conditions monitoring

All companies strive to eliminate work accidents. But still a lot of professions are exposed to different hazardous conditions and many work injuries and even deaths occur everyday. Monitoring of working conditions is a very important part of labor protection. Combining wireless sensor networks with wearable technology is possible to significantly improve safety delivery capability of such systems and add new functionality to them. In this work we present the design results of the uniforms inbuilt wireless sensor node for working conditions monitoring. The node is able to signalize about employee presence in relation to working facilities, and to monitor the atmosphere for temperature and combustible gases concentration. It consists of light-weighted distributed pieces which are built in to clothes and has low power consumption. The average power consumption of the node is low enough for several weeks autonomous lifetime.