Energy Harvesting for Sensing Applications Update

If you are interested in the possibility of using energy harvesting
technology to power a wireless sensor network, there are few tools that you should consider to determine if this can make a difference in your next system design.

The 308-page book, Energy Harvesting for Autonomous Systems written by Stephen Beeby and Neil White of the University of Southampton and published by Artech House within the last year and provides chapters on RFID, photovoltaic, kinetic, and thermoelectric
energy harvesting as well as power management, energy storage and a a case study.

At Sensors Expo 2011 in Chicago, the Energy Harvesting
Track on Tuesday and Wednesday provide attendees special insight into the products and their applications from eleven companies.

For those seeking a focused in-depth look at energy
harvesting, the Power Management: Energy Harvesting & Storage Symposium on Monday provides information
from a dozen of the leading energy harvesting companies.

Accelerometer Designed for Continuous Operation to +482°C (+900°F)

At 482°C, Meggitt Sensing Systems Endevco model 6233C is rated considerably higher than the recently announced 6222S model that had a maximum 260°C operating environment. Available standard ranges of 10, 50 and 100 pC/g, the model 6233C offers a differential output with excellent performance stability over temperature and a wide operational bandwidth. The case isolated units have a standard three-point ARINC mounting and a rugged 2-pin 7/16-27 UNS 2A threaded receptacle. Target applications include high-precision vibration monitoring of high-temperature jet and turboprop engines, helicopter and rotorcraft HUMS, gas turbines and nuclear power plant machinery and equipment.

For more information about the Endevco model 6233C high temperature accelerometer, click here.

Accelerometer Operates in Continuous 260°C Environment

Designed for monitoring vibration in gas turbines, Meggitt Sensing Systems Endevco Model 6222S accelerometer is a piezoelectric design with sensitivities of either 20, 50 or 100 pC/g. The sensor’s piezoelectric technology does not require an external power supply. The unit’s balance differential output allows its use with any industry differential charge amplifier. The sensor’s packaging is a standard ARINC three-point mounting configuration using three mounting bolts. The unit has an integral two-pin 7/16-27 UNS-2A threaded receptacle as standard with an available three-pin option. 

In addition to gas turbine measurements the accelerometers are also well suited for high temperature and high reliability vibration monitoring in helicopter Health & Usage Monitoring Systems (HUMS) as well as ground and onboard aircraft engine monitoring.

For more information on Meggitt Sensing Systems Endevco Model 6222S – 100A Accelerometer, click here.

4-20 mA Transmitter Targets Accelerometer to Vibration Signal Conversion

Another recently introduced signal conditioning circuit for 4-20 mA output, specifically for vibration signals, comes from IMI Sensors – a division of PCB Piezotronics, Inc. Operating from loop-power supplied by a PLC, DCS or SCADA system, the stainless steel housed 682A09 converts the 100 mV/g output from an accelerometer to a 4-20 mA vibration monitoring signal. The converted signal can monitor machine health for early failure detection to avoid costly downtime. The hermetically sealed design has a 2-pin MIL connector input and 3-pin MIL connector output to cope with harsh environments.

For more information about IMI Sensors 682A09 4-20 mA vibration transmitter click here.

Energy Harvesting for Enthusiasts

Anyone who likes the idea of something for nothing has to be interested in energy harvesting, getting the energy to avoid reliance on traditional energy sources such as batteries, for free – once the initial hardware investment has been made. Today, in addition to solar, wind and falling or flowing water, vibration, RF, heat and other techniques are powering many products, especially sensor-based applications.

For industrial applications, one of the more intriguing energy harvesting techniques involves vibration. In a factory environment, the movement of rotating equipment provides a constant vibration source. A carefully designed system can use this low level of vibration and a piezoelectric energy harvesting transducer to power a sensor and its associated circuitry. Without the need to charge or replace a battery, the sensor can provide low maintenance feedback regarding the normal or abnormal operation of equipment for fault monitoring and downtime prevention. Several companies are involved in the development of the energy harvesting devices as well as other critical components in the ultra-low power consuming sensor circuits.

Those who are interested in more information may want to check out the Power Management: Energy Harvesting & Storage symposium (http://www.sensorsexpo.com/pre-conference-symposia/symposium-3-power-management-energy-harvesting-storage) at Sensors Expo, June 7 in Chicago, IL