.The power generating type must be chosen considering the type of energy to be gathered from the environment, whether light, vibration or heat. Mostly solar, piezoelectric, or thermoelectric are used. power IC for use with the power generating element efficiently should gather the electric power from that element without energy loss. The generated power for each energy harvesting devices changes according to the size and the surrounding environment. It is necessary to consider the following. Selecting a power IC which is suitable for the power generating element. Regarding the selection of wireless communication type between wireless sensor network and computer , the selection can be attached for the power generating element. The communication distance, the type of network, the data transmission speed and the power consumption should be analyzed.
ZigBee ,EnOcean and Bluetooth technologies are low power consumption wireless technologies in the present. There is a point to be considered in energy harvesting, identify power generation and power consumption of the device. This is why of the device will not work if the energy generating is smaller than the consumed power of the device. Although the energy harvesting property of power generating devices are developing day by day, it is less possibility supply continuous power to a device . (Anon., n.d.).To overcome this problem generating energy is collected in a capacitor and execute sensor operation at intervals, resulting in a manner which balances the energy harvesting and power consumption. So the designer requires to have an good understanding of the surrounding environment of the power generating area and amount of the power generated and how long it is required.
Smart RF Energy Generating
RF power harvesting (RFH) is seems as a good method for the proactive power replenishment of next generation wireless networks. Unlike other power generating techniques that rely on the surrounding area, RFH can be on demand or predictable and as such it is better suited for supporting quality of service based applications. (Anon., n.d.) .

• Energy Harvesting MEMS

(Armstrong, n.d.)Piezoelectric micro-electromechanical systems (MEMS) have been found a technology for generating small amplitude of vibrations. This technology gives ability for prevents replacing chemical batteries and complex wiring in circuits, moving us closer toward battery-less autonomous sensors systems and networks. The advantages of piezoelectric MEMS energy generating devices are follows sufficient voltage output, bandwidth, compactness, operating frequency, amplitude of input vibration, cost ,lifetime High power density ratio and wide bandwidth of resonance frequency . Lead-free piezoelectric materials Grown films , grain textured piezoelectric materials and thin films those have high piezoelectric coefficients are recently advancements made toward increasing the electromechanical energy conversion of piezoelectric generating devices . Nonlinear resonators are highly promising to deliver more electric power from the piezo electric beam with wide bandwidth. (Anon., n.d.).
According to Armstrong, at the low part of the power spectrum are the Nano power conversion requirements of energy generating devices likewise those mostly find in IoT devices, which require the use of power conversion ICs which execute in low levels of current and power.. These can be 10 micro- 1Nano amps of current,. State of the art and off the shelf EH technology for example in vibration energy harvesting and indoor or smart wearable photovoltaic cells, yield power levels in the order of milli watts under typical operating conditions. While such power levels may appear restrictive, the operation of harvesting elements over a number of years can mean that the technologies are broadly comparable to long-life primary batteries, both in terms of energy provision and the cost per energy unit provided. Moreover , systems relating with EH will typically be capable of recharging after depletion something which systems powered by primary batteries cannot do. Nevertheless, most implementations will use an ambient energy source as the primary power source, but will supplement it with a primary battery that can be switched in if the sufficient energy source goes away or is disrupted.
The Energy harvesting base wireless sensor network will be widely contribute to improve of constructing, using, maintaining and managing these infrastructures, and reducing environmental pollution obtained to host of Olympic Games in India as Mr. Sekine, obtaining for IoT era, the wireless sensor market expects rapid development with implementing billion of wireless sensors in worldwide. But the battery of each sensor has critical problem with it lifetime and its replacement. According to the iBeacon service which was announced by Apple company also requires battery based Beacon units for its service. Since it hasn’t solved battery-life and its replacement issues, therefore the market hasn’t been exponentially expanded, yet. The wireless sensor market has same issues. Cypress Energy Harvesting solution can solve these issues.