Radio sensors can monitor installations at locations which are difficult to get to and thus support automation. The energy supply is an important consideration in such applications. In order to dispense with the need for batteries and the associated servicing work, it is possible to use energy from the surrounding environment: energy harvesting.
Piezoelements convert the kinetic energy from vibrations or shocks in the surrounding environment into electrical energy, and when equipped with the appropriate electronics they can create an autonomous system.
The robust DuraAct piezo actuators from PI Ceramic (PIC) are laminated in plastic and particularly well suited to energy harvesting. They are simple to handle and can even utilize displacements up to the millimeter range. What's more, they are particularly reliable and durable.
PIC also provides matching transducer and storage electronics as initial prototypes. The unit is small and can therefore be used almost anywhere, with very low intrinsic power consumption. Smaller dimensions in chip-size are currently being investigated.
The energy harvesting system operates over a large frequency range from a few hertz to several thousand hertz. For short periods of time it achieves a power output up to the milliwatt range, which can be supplied at a stable output voltage of between 1.8 and 5 V. This is sufficient to operate many commercial electronic circuits and systems.