There are some very exciting high growth projections for wireless sensing for the Automation industry. More sensors mean more process efficiency, lower operating costs, lower maintenance costs, higher reliability, and greater safety. Wireless sensing provides the opportunity to install masses of sensors with virtually no cost of installation by reducing the need for cables carrying the signals from the field to the control room. Wiring costs can easily be 80%, or more in a hazardous area, of the total cost of installing a new sensor. Who wouldn’t like to get the same job for one-fifth of the cost or five times as many sensors for the budget? And it is not just the cost of the installation; there are many cases where plant has to be shutdown to facilitate installation adding another massive sum to the cost of new sensors.
Most of us routinely use wireless (cell phones, Wi-Fi) for communication, and the potential for machine-to-machine wireless communication is considered to be even larger. Wireless transmission of sensor data is now well established as a reliable method of monitoring industrial plants. It is even being perceived by some users as more reliable and maintenance free than hard wiring.
This whole new approach to Automation has been made possible by the convergence of new technologies:
- Low power electronics including microprocessors with sleep modes
- RF transmission systems that use digitally encoded signals (e.g. digital television and Wi-Fi) with an order of magnitude less power required than older analogue systems
- New energy harvesting techniques
So why is there so much interest in energy harvesting? Simply, you cannot get the full benefit of wireless unless the power source is also wireless. This means either a battery or some form of energy harvester. Until recently, the usual power source available to power a wireless sensor node or network (WSN) has been batteries. With their limited and non-deterministic life span, hazardous content, shipping and disposal requirements, batteries alone are not likely to provide a power source that will last the life cycle of the WSN application without maintenance intervention. The ideal solution is an energy harvester that is “fit and “forget” and will have a lifespan in excess of the WSN that it is powering.
More info here.