ABSTRACT
A smart environment is a “physical world that is richly and invisibly interwoven with sensors, actuators, displays, and computational elements, embedded seamlessly in the everyday objects of our lives, and connected through a continuous network” (Cook 2005). In such a system, distributed
and remote measurements are done using wireless modules or nodes. These modules may use Bluetooth, ZigBee, Wi-Fi, or serial proprietary communication protocols and fi rmware that supports hopping, meshing, TCP/IP, serial bit banging etc. The recent advances in wireless sensor networking technology have led to the development of low cost, low power, multifunctional sensor nodes. Sensor nodes enable environmental sensing together with data processing. Instrumented with a variety of sensors, such as temperature, humidity and volatile compound detection, that monitoring different environments. They are able to network with other sensor systems and exchange data with external users (RuizGarcia et. al., 2009). One such devices is the Tag4M Wi-Fi tag which is an embedded system incorporating a sensor interface, a 32-bit CPU, memory, eCos real time operating system, complete Wi-Fi networking solution, network stack, crypto accelerator, power management system and real time clock (G2 Microsystems1 2008; G2 Microsystems2 2008). The Tag4M Wi-Fi tag has ultra low power Wi-Fi capability which makes it suitable for sensing applications where battery power management is critical. The requirement for battery power is represented by a current peak up to 0.5 A, with a very short pulse duration of about 1-2 ms (Folea and Ghercioiu 2008; Ghercioiu et al., 2007).
