> continued visit our new sensors microsite... www.avnet-abacus.eu/sensors
Energy harvesting brings new opportunities for wireless sensor networks
sensing your world
showcasing a huge range of sensor technologies from the world’s leading sensor manufacturers
There are however a number of items to consider when selecting a wireless sensor solution for any application. The nature of the application will determine whether a wired or wireless solution is most appropriate.
Accelerometer Air Quality Sensors Encoders Hall Effect Humidity Inductive Light Liquid Quality Sensors Magnetoresistive Potentiometric Pressure Pyroelectric Infrared
Of course the first consideration must be for what is being measured and therefore what type of sensor is required. Furthermore, the design engineer will need to consider the response time and accuracy level required for their specific application as different products and technologies vary widely. Additionally, in a wireless solution, the frequency in which the measurement needs to be transmitted will have a significant impact on the drain of the battery or power solution and must be carefully reviewed. A third consideration is the range that the signal must be transmitted over as this will vary widely between applications. The longer the range, the more power will be required to transmit a signal and finally the frequency in which the signal will be transmitted must be addressed. Laws vary by country and region as to which parts of the wireless spectrum are available for use without specific licenses. Sensors
Thermistors Thermocouple Ultrasonic
specialists at distributor Avnet Abacus are able to provide guidance and support to design engineers through all of these considerations.
A major drawback to moving toward large scale wireless sensor network installations has been the poor reliability and limited useful life of the batteries needed to supply the energy to the sensor, transmitter, processor and other electronic elements of the system.
Wireless sensor networks use batteries or energy harvesting techniques to power the device. Networks where the range is up to 300m are considered to be the ‘micropower world’ and it is in this area where significant developments have been made with the advent of solid state batteries with in-built power management functionality that use less space than conventional coin cell batteries and which are designed to last the life of the product, so eliminating maintenance costs and accessibility issues. Combining energy harvesting transducers, an energy processing power module, low power sensor, an energy aware microcontroller, and an optimised RF radio link delivers the reality of long life, maintenance-free wireless sensor networks.
Metal RTDs Gyroscope IR Thermopile GE Sensing www.avnet-abacus.eu
T6613 Compact CO² Sensor Module
6 focus magazine - issue 11
Energy harvesting based autonomous wireless sensor nodes can be cost-effective and convenient. The use of energy harvesting removes one of the key factors limiting the proliferation of wireless nodes: the scarcity of power sources having the characteristics necessary to deliver the energy and power to the sensor node for a number of years without battery replacement. Significant economic
| Page 2
| Page 3
| Page 4
| Page 5
| Page 6
| Page 7
| Page 8
| Page 9
| Page 10
| Page 11
| Page 12
| Page 13
| Page 14
| Page 15
| Page 16